SELECTIVE ANDROGEN RECEPTOR MODULATORS
The androgen receptor (AR) is part of the steroid nuclear hormone receptor subfamily
that also includes the mineralocortocoid receptor (MR), the progesterone receptor (PR), the
estrogen receptor (ER), and the glucocorticoid receptor (GR). Endogenous steroidal
androgens (e.g. testosterone and 5a-dihydrotestosterone (DHT)) are the major circulating sex
hormones and play a role in the regulation of various physiological processes. Anabolic (e.g.
tissue building) effects of androgens include increasing muscle mass and strength and
increasing bone mass and density, whereas androgenic (e.g. masculinizing) effects include
development of the internal reproductive tissues (e.g. prostate and seminal vesicles), the
external genitalia, male hair growth patterns, and libido. Clinically, androgen replacement
therapy has been used in the treatment of various conditions and disorders including male
hypogonadism, muscle wasting diseases, and cachexia.
However, steroidal androgen therapy is limited. For example, preparations of
steroidal androgens have been found to suffer from rapid degradation in the liver leading to
poor oral bioavailability and short duration of activity following parenteral administration,
variations in plasma levels, hepatotoxicity, or cross reactivity with other steroid hormone
receptors, such as GR, MR, and PR. Further, it has been observed that oral anabolic non
steroidal and steroidal androgens produce greater lowering of high-density lipoprotein (HDL)
in eugonadal men and women relative to parenteral androgens. Lowering of HDL has been
suggested to result in poor cardiovascular health outcomes.
Therefore, there remains a need for alternatives to steroidal androgen therapy. More
particularly, there remains a need for nonsteroidal AR agonists which bind to AR with
greater affinity relative to the other steroid hormone receptors. Even more particularly, there
remains a need for tissue-selective androgen receptor modulators (SARMs) which display
androgen agonist activity in anabolic tissues such as muscle or bone, but only partial agonist,
partial antagonist or antagonist activity in androgenic tissues such as the prostate or seminal
vesicle. SARMs may provide the benefits of traditional anabolic steroids, such as muscle or
bone growth, while minimizing the proliferative or hypertrophic effects on sex tissues.
Published international patent applications, WO09/105214 and WO06/124447,
disclose small molecule, non-steroidal SARMs. Still, there exists a need for new non
steroidal SARM compounds with improved potency and/or pharmacokinetic characteristics,
such as exposure bioavialability. There also exists a need for efficacious SARM compounds.
Additionally, there exists a need for SARM compounds that build muscle mass without the
side effect of prostate gland enlargement. Androgens and SARM compounds are known to
decrease HDL at efficacious exposures when delivered via oral route. Thus, there exists a
need for SARM compounds that do not significantly decrease HDL levels. The present
invention provides preferred androgen receptor modulating compounds which have a
minimum risk of HDL lowering at efficacious doses when delivered via a transdermal route.
Therefore, the present invention provides novel compounds which are AR agonists.
More preferably, the compounds are SARMs. Such new compounds could address the need
for potent, effective treatment of muscle atrophy, hypogonadism, or cachexia with minimum
risk of prostate enlargement or HDL lowering.
The present invention provides a compound of formula:
wherein
n is 1 or 2;
X is -CH 2- or -0-;
R1 is -CH 3 or -CH 2CH3;
R2 is - H or -CH 3;
R3 is - H or -OH;
wherein R is - H when X is -0-;
or a pharmaceutically acceptable salt thereof.
The present invention further provides a method for the treatment or prevention of
muscle atrophy in a patient comprising administering to a patient in need of such treatment or
prevention an effective amount of a compound of the present invention, or a
pharmaceutically acceptable salt thereof. In a particular aspect, the present invention
provides a method of treating or preventing muscle atrophy associated with disuse, trauma,
immobilization, spinal cord injury, or stroke comprising administering to a patient in need
thereof an effective amount of a compound of the present invention. Even more particularly,
the present invention provides a method of treating or preventing muscle atrophy associated
with hip or knee replacement, hip fracture, spinal cord injury, or stroke comprising
administering to a patient in need thereof an effective amount of a compound of the present
invention.
Additionally, the present invention provides a pharmaceutical formulation comprising
a compound of the invention, or a pharmaceutically acceptable salt thereof, and a
pharmaceutically acceptable carrier, diluent, or excipient. The present invention provides a
pharmaceutical composition comprising a compound of the invention, or a pharmaceutically
acceptable salt thereof, and one or more pharmaceutically acceptable carriers, diluents, or
excipients. In a further embodiment, the present invention provides a pharmaceutical
composition comprising a solvate, wherein the solvate molecules include ethanol and
isopropanol. In a further embodiment, the present invention provides a pharmaceutical
composition for the treatment or prevention of muscle atrophy associated with hip or knee
replacement, hip fracture, spinal cord injury, or stroke comprising a compound of the
invention in combination with one or more pharmaceutically acceptable carriers, diluents or
excipients. In yet a further embodiment, the pharmaceutical composition further comprises
one or more other therapeutic agents. In another embodiment, the pharmaceutical
composition has minimal risk of lowering HDL.
Further, the present invention provides a compound of the invention, or a
pharmaceutically acceptable salt thereof, for use in therapy, in particular for treating or
preventing muscle atrophy. Even further, the present invention provides a compound of the
invention, or a pharmaceutically acceptable salt thereof, for use in treating muscle atrophy.
In a further embodiment, the present invention provides a compound of the invention, or a
pharmaceutically acceptable salt thereof, for use in therapy, in particular for treating or
preventing muscle atrophy associated with hip or knee replacement, hip fracture, spinal cord
injury, or stroke. Even further, the present invention provides a compound of the invention,
or a pharmaceutically acceptable salt thereof, for use in treating or preventing muscle atrophy
associated with hip or knee replacement, hip fracture, spinal cord injury, or stroke.
Furthermore, the present invention provides the use of a compound of the invention, or a
pharmaceutically acceptable salt thereof, for the manufacture of a medicament for treating or
preventing muscle atrophy. In a further embodiment, the present invention provides the use
of a compound of the invention, or a pharmaceutically acceptable salt thereof, for the
manufacture of a medicament for treating or preventing muscle atrophy associated with hip
or knee replacement, hip fracture, spinal cord injury, or stroke.
The present invention also provides a method of treating or preventing hypogonadism
or cachexia by administering an effective amount of a compound of the present invention, or
a pharmaceutically acceptable salt thereof. The present invention further provides a method
for the treatment or prevention of hypogonadism or cachexia in a patient comprising
administering to a patient in need of such treatment or prevention an effective amount of a
compound of the present invention, or a pharmaceutically acceptable salt thereof. Further,
the present invention provides a compound of the invention or a pharmaceutically acceptable
salt thereof for use in therapy, in particular for treating or preventing hypogonadism. Even
further, the present invention provides a compound of the invention, or a pharmaceutically
acceptable salt thereof, for use in treating or preventing hypogonadism. Also, the present
invention provides a compound of the invention, or a pharmaceutically acceptable salt
thereof, for use in therapy, in particular for treating or preventing cachexia. Even further, the
present invention provides a compound of the invention, or a pharmaceutically acceptable
salt thereof, for use in treating or preventing cachexia. Furthermore, the present invention
provides the use of a compound of the invention, or a pharmaceutically acceptable salt
thereof, for the manufacture of a medicament for treating or preventing hypogonadism or
cachexia. The present invention provides the use of a compound of the invention, or a
pharmaceutically acceptable salt thereof, for the manufacture of a medicament for the
treatment or prevention of hypogonadism or cachexia.
The present invention also provides a method of preventing fall-related injuries in
elderly fallers with muscle weakness by administering an effective amount of a compound of
the present invention, or a pharmaceutically acceptable salt thereof. The present invention
further provides a method for the prevention of fall-related injuries in elderly fallers with
muscle weakness by administering an effective amount of a compound of the present
invention, or a pharmaceutically acceptable salt thereof. Further, the present invention
provides a compound of the invention or a pharmaceutically acceptable salt thereof for use in
therapy, in particular for preventing fall-related injuries in elderly fallers with muscle
weakness. Even further, the present invention provides a compound of the invention, or a
pharmaceutically acceptable salt thereof, for use in preventing fall-related injuries in elderly
fallers with muscle weakness. Furthermore, the present invention provides the use of a
compound of the invention, or a pharmaceutically acceptable salt thereof, for the
manufacture of a medicament for preventing fall-related injuries in elderly fallers with
muscle weakness.
The present invention also provides a method of reversing, treating, or preventing the
adverse effects of androgen deprivation therapy (ADT) by administering an effective amount
of a compound of the present invention, or a pharmaceutically acceptable salt thereof. The
present invention further provides a method for the reversal, treatment, or prevention of the
adverse effects of ADT in a patient comprising administering to a patient in need of such
treatment or prevention an effective amount of a compound of the present invention, or a
pharmaceutically acceptable salt thereof. Further, the present invention provides a
compound of the invention or a pharmaceutically acceptable salt thereof for use in therapy, in
particular for reversing, treating, or preventing the adverse effects of ADT. Even further, the
present invention provides a compound of the invention, or a pharmaceutically acceptable
salt thereof, for use in reversing, treating, or preventing the adverse effects of ADT.
Furthermore, the present invention provides the use of a compound of the invention, or a
pharmaceutically acceptable salt thereof, for the manufacture of a medicament for reversing,
treating, or preventing the adverse effects of ADT.
The present invention also encompasses intermediates and processes useful for the
synthesis of a compound of the present invention.
A particular method in which a compound of the present invention is believed useful
is in the treatment or prevention of muscle wasting conditions or muscle atrophy. Muscle
wasting may occur as a natural result of aging (e.g. sarcopenia). Alternatively, muscle
atrophy may result as a secondary consequence of disuse or inactivity (e.g. following hip or
knee replacement or hip fracture), trauma, immobilization (e.g. casting or splinting of limbs),
as well as spinal cord injury or stroke. (See, Hafer-Macko et al., J. Rehab. Res. Develop.;
45(2): 261-272 (2008)) Thus, the term "muscle atrophy," as used herein, is synonymous
with muscle wasting and refers to a condition wherein a patient has lost muscle mass due to a
health condition such as cancer, HIV, or as a result of extended period(s) of inactivity or as
an adjunct treatment following surgery where significant periods of inactivity have or may
have resulted in loss of muscle mass. Further as used herein, the term "muscle atrophy
associated with disuse, trauma, immobilization, spinal cord injury or stroke" refers to muscle
atrophy that occurs as a secondary consequence to the incidence of disuse or inactivity (e.g.
following hip or knee replacement or hip fracture), trauma, immobilization (e.g. casting or
splinting of limbs), spinal cord injury or stroke. Furthermore, in the context of spinal cord
injury or stroke, a compound of the present invention may be used as an adjunct to standard
rehabilitation therapy (e.g. physical or occupational therapy, exercise, assisted walking, and
/or strength training). Even further, a compound of the present invention may be used for
treating or preventing co-morbidities as a result of falls due to lower limb muscle atrophy as
evidenced by changes in objective measurements that assess risk of falls in the elderly (See
Close and Lord, BMJ 201 1; 343:d5153).
Another particular method in which a compound of the present invention is believed
useful is in the reversal, treatment, or prevention of the adverse effects of hormone therapy
for prostate cancer, also called androgen deprivation therapy (ADT) or androgen suppression
therapy.
Figure 1 is a spectrogram of a representative X-ray powder diffraction (XRD) pattern
for 2-chloro-4-[[(lR,2R)-2-hydroxy-2-methyl-cyclopentyl]amino]-3-methyl-benzonitrile
crystalline Form 1. The XRD spectrogram was obtained as described in the Example 1C
below. Figure 2 is a spectrogram of a representative XRD pattern for 2-chloro-4-[[(lR,2R)-
2-hydroxy-2-methyl-cyclopentyl]amino]-3-methyl-benzonitrile crystalline Form 2. The
XRD spectrogram was obtained as described in the Example ID below. Figure 3 is a
spectrogram of a representative XRD pattern for 2-chloro-4-[[(lR,2R)-2-hydroxy-2-methylcyclopentyl]
amino]-3-methyl-benzonitrile crystalline ethanol solvate. The XRD spectrogram
was obtained as described in the Example IE below. Figure 4 is a spectrogram of a
representative XRD pattern for 2-chloro-4- [[( 1R,2R)-2-hydroxy-2-methylcyclopentyl]
amino]-3-methyl-benzonitrile crystalline isopropanol solvate. The XRD
spectrogram was obtained as described in the Example IF below.
The term "effective amount" is taken to mean the dose or doses of a compound of the
invention required to treat muscle atrophy, hypogonadism, or cachexia in a mammal. A
compound of the present invention is generally effective over a wide dosage range. For
example, dosages per day normally fall within the range of about 0.001 to about 10 mg/kg of
body weight. In some instances dosage levels below the lower limit of the aforesaid range
may be more than adequate, while in other cases still larger doses may be employed while
maintaining a favorable benefit/risk profile, and therefore the above dosage range is not
intended to limit the scope of the invention in any way. It will be understood that the amount
of a compound actually administered is likely to be determined by a physician, in the light of
the relevant circumstances, including the condition to be treated, the chosen route of
administration, the actual compound or compounds administered, the age, weight, and
response of the individual patient, and the severity of the patient's symptoms.
The term "treating" (or "treat" or "treatment") as used herein refers to prohibiting,
restraining, slowing, stopping, or reversing the progression or severity of an existing
symptom, condition, or disorder. The term "preventing" (or "prevent" or "prevention") as
used herein refers to prohibiting, restraining, or inhibiting the incidence or occurrence of a
symptom, condition, or disorder. Symptoms, conditions, or disorders may present as "acute"
or "chronic" events. In an acute event compound is administered at the onset of symptom,
condition, or disorder and discontinued when the event disappears, whereas a chronic
symptom, condition, or disorder is treated throughout the course of the event. The present
invention contemplates both acute and chronic treatment.
A compound of the present invention may react with any of a number of inorganic
and organic acids to form pharmaceutically acceptable acid addition salts. Pharmaceutically
acceptable salts and common methodology for preparing them are well known in the art.
See, e.g., P. Stahl, et al. Handbook of Pharmaceutical Salts: Properties, Selection and Use,
2nd Revised Edition (Wiley-VCH, 201 1); S.M. Berge, et al., "Pharmaceutical Salts," Journal
of Pharmaceutical Sciences, Vol. 66, No. 1, January 1977.
The skilled artisan will appreciate that the compounds of the invention are comprised
of a core that may contain up to three chiral centers, as illustrated in 1(a) below:
1(a)
Although the present invention contemplates all individual enantiomers, as well as
mixtures of the enantiomers of said compounds including racemates, the compounds with the
absolute configuration as illustrated in 1(b) below are preferred compounds of the invention.
1(b)
Isomers of compounds of the invention are labeled as isomer 1, isomer 2, etc.,
beginning with the first to elute (lower retention time) from the chromatographic separation
method employed and disclosed herein.
The skilled artisan will appreciate that additional chiral centers may be created in the
compounds of the invention by the selection of certain variables. The present invention
contemplates all individual enantiomers or diastereomers, as well as mixtures of the
enantiomers and diastereomers of said compounds including racemates.
The skilled artisan will also appreciate that the Cahn-Ingold-Prelog (R) or (S)
designations for all chiral centers will vary depending upon the substitution patterns of the
particular compound. The single enantiomers or diastereomers may be prepared beginning
with chiral reagents or by stereoselective or stereospecific synthetic techniques.
Alternatively, the single enantiomers or diastereomers may be isolated from mixtures by
standard chiral chromatographic or crystallization techniques at any convenient point in the
synthesis of compounds of the invention. Single enantiomers and diastereomers of
compounds of the invention are a preferred embodiment of the invention.
As a modulator of AR, a compound of the present invention may be useful for
treating muscle atrophy. Further, a compound of the present invention may be useful for
treating hypogonadism. Even further, a compound of the present invention may be useful for
treating cachexia. Another embodiment of the present invention is a compound of the
present invention for treating a disease or condition capable of being improved or prevented
by modulation of AR. A further embodiment of the present invention is the use of a
compound of the present invention for the manufacture of a medicament for treating a
disease or condition capable of being improved or prevented by modulation of AR.
A compound of the present invention is preferably formulated as pharmaceutical
compositions administered by a variety of routes. Preferably, such compositions are suitable
for transdermal delivery and are formulated as a patch, a topical gel, a topical spray, or a
topical cream. Such pharmaceutical compositions and processes for preparing same are well
known in the art. See, e.g., Remington: The Science and Practice of Pharmacy (A. Gennaro,
et a , eds., 21st ed., Mack Publishing Co., 2005).
Although all of the exemplified compounds of the invention are androgen receptor
agonists, certain classes of compounds are preferred. The following paragraphs describe
such preferred classes:
a) n is 1;
b) n is 2;
d) X is -O-;
e) R^s -CHs;
f) R1 is -CH 2CH3;
g) R2 is -CH 3;
h) R2 is H;
i) R is -H;
j ) R is -OH;
k) R1 is -CH 2CH3 when R3 is -OH;
1) R1 is -CH 2CH3 when X is -0-;
m) R1 is -CH 3 when X is -CH 2- ;
n) the compound of the present invention is the free base;
o) the compound of the present invention is the ethanol solvate;
p) the compound of the present invention is the isopropanol solvate.
A preferred embodiment of the compounds of the present invention relates to
compounds of the invention of the following formula,
wherein
n is 1 or 2;
R1 is -CH 3 or -CH 2CH3;
R2 is - H or -CH 3;
R3 is - H or -OH;
or a pharmaceutically acceptable salt thereof.
Another preferred embodiment of the compounds of the present invention relates to
compounds of the invention of the following formula,
wherein
n is 1 or 2;
R1 is -CH 3 or -CH 2CH3;
R2 is - H or -CH 3;
or a pharmaceutically acceptable salt thereof.
A further preferred embodiment of the compounds of the present invention relates to
compounds of the following formula,
wherein
R1 is -CH
R2 is - H or -CH 3;
R3 is - H or -OH;
or a pharmaceutically acceptable salt thereof. In said embodiment, it is preferred that R1 is
-CH 3. It is also preferred in said embodiment that R1 is -CH 2CH3 when R is -OH.
Another further preferred embodiment of the compounds of the present invention
relates to compounds of the following formula,
wherein
R1 is -CH 3 or -CH 2CH3;
R2 is - H or -CH 3;
R3 is - H or -OH;
or a pharmaceutically acceptable salt thereof. In said embodiment, it is preferred that R1 is
-CH 3. It is also preferred in said embodiment that R1 is -CH 2CH3 when R3 is -OH.
Another preferred embodiment of the compounds of the present invention relates to
compounds of the following formula,
wherein
R1 is -CH 3 or -CH 2
R2 is - H or -CH 3;
or a pharmaceutically acceptable salt thereof. In said embodiment, it is preferred that R1 is
-CH 2CH3.
A further preferred embodiment of the compounds of the present invention relates to
compounds of the following formula,
wherein
R1 is -CH 3 or -CH 2CH3;
R2 is - H or -CH ;
or a pharmaceutically acceptable salt thereof. In said embodiment, it is preferred that R is
-CH 2CH3.
Another further preferred embodiment of the present invention relates to compounds
of the following formula:
or a pharmaceutically acceptable salt thereof.
An especially preferred embodiment of the present invention relates to the compound, 2-
chloro-4-[[(lR,2R)-2-hydroxy-2-methyl-cyclopentyl]amino]-3-methyl-benzonitrile
or a pharmaceutically acceptable salt thereof.
Another especially preferred embodiment of the present invention relates to the compound,
2-chloro-4-[[(lS,2R)-2-hydroxy-2-methyl-cyclopentyl]amino]-3-methyl-benzonitrile,
or a pharmaceutically acceptable salt thereof.
As used herein, the following terms have the meanings indicated: "abs" refers to
absolute; "CMV promoter" refers to cytomegalovirus promoter; "Bn" refers to benzyl;
"BOC" refers to rt-butoxycarbonyl; "CS-FBS" refers to charcoal stripped fetal bovine
serum; "DMAC" refers to dimethylacetamide; "DMEM" refers to Dulbecco's Modified
Eagle Medium; "DMF" refers to dimethylformamide "DMSO" refers to dimethyl sulfoxide;
DTT" refers to dithiothreitol; "EDTA" refers to ethylenediaminetetraacetic acid; "EtOAc"
refers to ethyl acetate; "EtOH" refers to ethanol; "Ex" refers to Example; "FBS" refers to
fetal bovine serum; "h" refers to hours; "HEK" refers to human embryonic kidney; "HEPES"
refers to 4-(2-hydroxyethyl)-l-piperazineethanesulfonic acid; "IPM" refers to isopropyl
myristate; "LDA" refers to lithium diisopropyl amide; "MCPBA" refers to metachloroperoxybenzoic
acid; "MeOH" refers to methanol; "MTBE" refers to methyl t rt-butyl
ether; "min" refers to minutes; "NCS" refers to N-chlorosuccinimide; "Prep" refers to
Preparation; "rel" refers to relative; "SFC" refers to supercritical fluid chromatography;
"TBAF" refers to tra-butylammonium fluoride; "TBDMS" refers to t-butyldimethylsilyl;
"TBDPS" refers to t-butyldiphenylsilyl; "TEA" refers to triethylamine; "TEMPO" refers to
2,2,6,6-tetramethylpiperidine-N-oxide; "THF" refers to tetrahydrofuran; "TMS" refers to
trimethylsilyl; "TK promoter" refers to thymidine kinase promoter; and "XRD" refers to xray
diffraction.
In the schemes below, all substituents unless otherwise indicated, are as previously
defined. The reagents and starting materials are generally readily available to one of
ordinary skill in the art. Others may be made by standard techniques of organic and
heterocyclic chemistry which are analogous to the syntheses of known structurally-similar
compounds and the procedures described in the Preparations and Examples which follow
including any novel procedures.
The compounds of the present invention comprise up to three chiral centers or more.
It will be recognized by one skilled in the art that there are common techniques useful for
separating and identifying diastereomers or enantiomers. Such techniques include silica gel
chromotagraphy to separate diastereomers, chiral chromatography to separate enantiomers,
synthesis using starting materials of known configuration, or making use of synthetic
techniques which are known to provide defined stereochemistry at a chiral center, or one
relative diastereomeric configuration, such as cis or trans.
Scheme 1
Scheme 1 depicts formation of amino alcohols of formula (8).
In Step A, a cyclic olefin of formula (1) is oxidized to an epoxide of formula (2). The
olefin (1) is treated with an oxidizing agent, such as MCPBA, in an inert solvent, such as
dichloromethane at 0 to 40 °C for 2 to 24 h to obtain the epoxide (2).
In Step B, an epoxide of formula (2) is opened to provide the azido-alcohol of
formula (3). The reaction proceeds in a solvent mixture of water and MeOH using an azide
source, such as sodium azide, in the presence of ammonium chloride at a temperature of 50
to 70 °C for a period of 2 to 24 h. Alternatively, the reaction can be performed in a solvent
such as DMF, with or without the addition of a Lewis acid, such as lithium perchlorate, at 50
to 100 °C, preferably at about 90 °C for 12 to 72 h.
In Step C, the azide (3) is reduced to the amine of formula (4), which can be reacted
directly with a fluoro-benzonitrile (Scheme 5). The amine (4) can be obtained by
hydrogenation over a palladium catalyst, such as 10% palladium on carbon, in an inert
solvent, such as MeOH or EtOH at about 10 to 40 °C.
Alternatively, in Step B1, wherein R2 is methyl, the amine (4) can be obtained directly
from the epoxide (2) by reaction with ammonium hydroxide. The reaction proceeds in a
pressure vessel, in a solvent mixture of water/EtOH at 70 to 100 °C for about 2 to 18 h.
Regarding the amine of formula (4), wherein R2 = H, the methyl group can be
introduced using Steps D - G. Protection of the amine (4) with a BOC group in Step D gives
a protected amino-alcohol of formula (5). Preferred conditions for protection of the amine
use di-t rt-butyldicarbonate in a solvent mixture of acetone and water, in the presence of an
inorganic base such NaHCOs.
In Scheme 1 Step E, the protected amino-alcohol (5) is oxidized to the ketone (6).
The skilled artisan will recognize there are many methods to effect such an oxidation.
Preferred conditions use the well-known Swern oxidation. Thus, oxalyl chloride and DMSO
are combined in an inert solvent, such as dichloromethane or THF, at a temperature of -80 to
-60 °C and allowed to react at that temperature for a period of about 5 to 20 min to produce
the reactive intermediate dimethylchlorosulfonium chloride. This is followed by addition of
the alcohol (5), again at a temperature of -80 to -60 °C with reaction for a period of about 30
to 60 min. Finally, an organic base, such as TEA is added at the same temperature. At least
2 eq of the base is added, typically about 5 to 6 eq of TEA, and the reaction allowed to warm
to room temperature over 1 to 24 h.
Alternatively, the alcohol (5) can be oxidized using Anelli's conditions wherein
TEMPO is used catalytically, at a catalyst load of about 5 mol%, in the presence of
potassium bromide, in a biphasic solvent system of dichloromethane and aqueous sodium
hypochlorite, wherein potassium carbonate or other inorganic base is added to adjust the
sodium hypochlorite solution to about pH = 7.5 - 8. The TEMPO plus the alcohol (5) in
dichloromethane are cooled to a temperature of - 5 to 5 °C. The temperature is maintained
during the addition of the pH adjusted sodium hypochlorite solution and through the
remainder of the reaction which proceeds for about 20 min to 4 h to provide the ketone (6).
In Step F, the ketone (6) undergoes a Grignard reaction with methylmagnesium
bromide to provide the tertiary alcohol of formula (7). The reaction proceeds in an inert
solvent such as diethyl ether or THF. The Grignard reagent, methylmagnesium bromide, is
added slowly at a temperature of -80 to 5 °C, preferably at a temperature of - 5 to 5 °C, and
the reaction allowed to warm to room temperature over 12 to 48 h.
In Step G, the BOC protecting group is removed to give the unprotected amine of
formula (8). Acidic conditions for removal of boc groups, such as HCl in dioxane, are well
known in the art.
Different protecting groups can be employed by one skilled in the art. For Example,
the amine of formula (4) can be protected by bis-alkylation with benzyl bromide in a solvent
system, such as acetone/water, in the presence of an inorganic base, such as potassium
carbonate and heated at 40 °C to the reflux temperature of the solvent to provide the
dibenzylamino analog. Oxidation to the ketone and subsequent reaction with
methylmagnesium bromide can provide the tertiary amino-alcohol. The benzyl groups can
be removed using hydrogenation with Pd catalysts common in the art, such as palladium
black or palladium hydroxide on carbon.
One skilled in the art will recognize that some of the amines (4) are commercially
available as pure stereoisomers, such as (lR,2S)-2-aminocyclopentanol, thus obviating the
need for Steps A - C.
Scheme 2
Scheme 2 depicts formation of amino alcohols of formula (12) and (14), wherein
chirality is introduced using Jacobsen chemistry starting with a meso epoxide of formula (9)
(wherein Y = CH2, CH2CH2, or O).
For example, in Step A, a meso epoxide (9) undergoes an asymmetric ring opening
with azidotrimethylsilane using a chiral (salen)Cr(II) complex or a chiral (salen)Co(II)
complex, such as (lR,2R)-(-)-l,2-cyclohexanediamino-N,N'-bis(3,5-di-tbutylsalicylidene)
cobalt (II) (see Jacobsen, E.N, et al J Org. Chem. 1997, 62, 4197-4199).
The reaction is run neat at room temperature to 60 °C for 4 to 24 h.
In Step B, the azide (10) is reduced to the amine of formula ( 11), as previously
described for Scheme 1, Step C. This can be followed by removal of the TMS group using
fluoride anion, such as with TBAF to provide a chiral amino-alcohol (12).
If it is desired to insert the methyl group, then further protection group manipulation
can be done with the amine protected with a BOC group (Step D), removal of TMS (Step D1)
and then elaboration to the amino-alcohol of formula (14) following Steps E, F, and G which
are exactly analogous to Steps E, F, and G in Scheme 1.
Use of the other chiral salen complex, for example (lS,2S)-(-)-l,2-
cyclohexanediamino-N,N'-bis(3,5-di-t-butylsalicylidene)cobalt (II) gives access to molecules
with stereochemistry opposite to that shown for intermediates (10) to (14). After attachment
to the benzonitrile (Scheme 5) the diastereomers (amino and hydroxyl groups cis and trans)
can be conveniently separated using silica gel chromatography.
Scheme 3
. OH Step A /\... O H Step B . OMs
' OH OTBDMS ^"OTBDMS
( 15) abs ( 16) abs ( 17) abs
Step C N3 step D \ NH2
OTBDMS ^"^OTBDMS
( 8) abs ( 19) abs
Scheme 3 depicts formation of c -amino alcohols of formula (19), starting with a
chiral diol of formula (15) (wherein Y = CH2 or O).
In Step A, the diol (15) is reacted with TBDMSC1 (1.1 eq) in an inert solvent, such as
dichloromethane, in the presence of an organic base, such as TEA at room temperature for 2
to 5 days to give the silyloxy-hydroxy (16).
In Step B, the other hydroxyl group of (16) is mesylated using standard conditions to
give the mesylate (17). The reaction proceeds in an inert solvent, such as dichloromethane,
in the presence of 2,6-lutidine and an organic base such as triethylamine or
diisopropylethylamme using methanesulfonyl chloride. The reaction is performed at -20 °C
to room temperature for 4 to 24 h.
In Scheme 3, Step C, the mesylate (17) undergoes an S 2 displacement with sodium
azide to give the silyloxy azide of formula (18) wherein the stereochemistry at the reacting
carbon atom has been inverted. The reaction proceeds in an inert solvent, such as DMF at 60
to 130 °C for 2 days to 2 weeks. A phase transfer catalyst can be added, such as
tetrabutylammonium iodide.
In Step D, the silyloxy azide (18) is reduced to the silyloxy amine (19) using
conditions as previously described for Scheme 1, Step C.
Using the enantiomer of diol (15) gives access to the other cis enantiomer.
Scheme 4
(21 b) rel (22b) rel (23b) rel
Scheme 4 depicts formation of cyclopentyl and cyclohexylamino diols of formula
(23a) and (23b).
In Step A, the olefin of formula (20) is oxidized to the epoxides (21a) and (21b) using
MCPBA. The reaction is carried out in a biphasic solvent system of dichloromethane and
aqueous sodium bicarbonate at 0 °C to room temperature for 4 to 24 h. Additional MCPBA
and aqueous sodium bicarbonate can be added if needed. The diastereomeric epoxides are
separated by chromatography and carried forward separately in Steps B and C.
In Step B, the epoxides (21a) or (21b) are opened with sodium azide to give the
azido-alcohols (22a) and (22b) as previously described for Scheme 1, Step B.
Step C, reduction of the azide (22a) or (22b) is analogous to Scheme 1, Step C to
provide the amino-alcohols (23a) or (23b).
Scheme 4A
(25b) 1,2-cis-2,3-trans (25d) 1,2-trans-2,3-cis
Depicted in Scheme 4A is an alternative method for obtaining all four diastereomers
of amino-diols of formula (25a-d) using chemistry of Davies (see Aciro, C. et al Org.
Biomol. Chem. 2008, 6, 3751-3761; Aciro, C. et al Org. Biomol. Chem. 2008, 6, 3762-3770;
Bond, C.W. et al J. Org. Chem. 2009, 74, 6735-6748), particularly those of (25c) and (25d)
wherein the amine and the adjacent hydroxyl are cis to each other.
Dibenzyl allylic amine (24) can be obtained from cyclohexene by bromination,
followed by bromide displacement with dibenzylamine (see Davies). Alternatively, the
displacement can be done with benzylamine followed by benzylation of the benzyl allylic
amine with benzyl bromide. Alternatively, the dibenzyl allylic amine (24) could be obtained
directly by reductive amination on the corresponding ketone with dibenzylamine or
benzylamine, followed by benzylation with benzylbromide. The dibenzyl allylic amine of
formula (24), wherein R2 = Me, can be obtained by treating 2-methyl-2-cyclopenten-l-ol or
2-methyl-2-cyclohexene-l-ol with NCS and dimethylsulfide to give 5-chloro-l-methylcyclopentene
or the corresponding cyclohexene (see Funk, R. L. et al Tetrahedron 1985, 41,
3479-3495, compound 46b). The same displacement chemistry is applied as described
previously. One skilled in the art will recognize that the chloride could also be obtained by
treating the alcohol with thionyl chloride.
The skilled artisan will recognize that there are yet other methodologies available in
the literature that can be applied to obtain the diastereomers (25a-d). For example, starting
with the analogous acetamide (rather than the dibenzylamine), Whitten and coworkers (see
Whitten, J . P., McCarthy, J . R., and Whalon, M. R. J. Org. Chem. 1985, 50, 4399-4402)
obtained all four diasteromers (wherein n = 1, R2 = H). Furthermore, Donohoe and
coworkers (Blades, K., Donohoe, T. J., Winter, J . J . G., and Stemp, G. TetrahedronLett.,
2000, 41, 4701-4704), using the analogous allylic trichloroacetamide, accomplished syn
selectivity using catalytic osmium tetroxide in the presence of quinuclidine-N-oxide.
Scheme 5
Scheme 5 shows formation of compounds of the invention, amino benzonitriles of
formula (29) and (31) (stereochemistry not shown; R a is H or if X = CH2, R a can also be
OTBDPS; R4 = H or TBDMS).
In Step A, a fluoro-benzonitrile of formula (26) undergoes a nucleophilic aromatic
substitution with an amine of formula (27), whose synthesis is described in Schemes 1 - 4a.
The reaction proceeds in an inert solvent such as DMF, DMAC, or DMSO, preferably in a
solvent mixture of DMSO/water in a ratio of 7/1 to 10/1, in the presence of an inorganic
base, preferably lithium carbonate, but also sodium carbonate. The reaction is carried out in
a pressure vessel at 100 to 150 °C, preferably about 130 °C for 16 to 48 h. Alternatively, the
reaction can be successfully effected using microwave radiation, using simply an organic
base, such as diisopropylethylamine without additional solvent, at a temperature of 170 to
190 °C, preferably at 180 °C, to provide an amino benzonitrile of formula (28).
In Step B, amino benzonitriles (28) which contain a silyl protecting group (R a or R4)
are deprotected using fluoride anion, such as with TBAF, as described for Scheme 2, Step C.
If desired, compounds of formula (28), wherein R2 = R4 = H can be further elaborated
to compounds (31) (wherein R2 = CH3) using Steps C and D. In Step C, the hydroxyl of the
amino benzonitrile (28) is oxidized to the a-keto amino benzonitrile (30) using Swern
conditions as described previously for Scheme 1, Step E.
In Step D, the a-keto amino benzonitrile (30) undergoes a Grignard reaction with
methylmagnesium bromide to give the a-methyl-a-hydroxy amino benzonitrile of formula
(31). The reaction proceeds in an inert solvent, such as THF, at 0 °C to room temperature,
for a period of 15 min - 24 h.
The 2-chloro-3-alkyl-4-fluoro-benzonitrile of formula (26), wherein R1 = CH3 or
CH2CH3, is synthesized in one step from 2-chloro-4-fluoro-benzonitrile using a strong
organic base such as LDA, which can be generated in situ using diisopropylamine and nbutyllithium.
The LDA is added dropwise to the benzonitrile in a solvent such as THF, at a
temperature of -80 to -60 °C, preferably at -70 °C, for a period of 4 to 20 h. Iodomethane or
iodoethane are added at the same temperature, over about 2 to 3 h, and the temperature
allowed to raise to -10 to 5 °C for about 12 to 24 h.
Diastereomers or enantiomers of the amino benzonitriles (29) and (31) can be
separated by techniques such as silica gel chromatography or chiral chromatography.
Preparations and Examples
The following Preparations and Examples further illustrate the invention and
represent a typical synthesis of the compound of the invention. The reagents and starting
materials are readily available or may be readily synthesized by one of ordinary skill in the
art. It should be understood that the Preparations and Examples are set forth by way of
illustration and not limitation, and that various modifications may be made by one of
ordinary skill in the art.
The naming of the following Preparations and Examples is generally done using the
IUPAC naming feature in SYMYX® Draw version 3.2.NET.
Drawings wherein the absolute stereochemistry is known are labeled "absolute."
Drawings wherein only the cis or trans relationship between the amino and hydroxyl groups
is known are labeled "relative" and the corresponding drawing indicating the relative
stereochemistry using wedged bonds. Regarding stereochemical designation, the
diastereomeric relationship on the monocyclic ring is generally indicated using the cis/trans
nomenclature. The diastereomeric relationship on those few compounds which have three
chiral centers on the monocyclic ring are designated, for example, by re/-(lR,2S,3S),
indicating that the (1R,2S,3S) isomer and the (1S,2R,3R) isomer are both present in the
diastereomeric mixture.
Preparation 1
2-Chloro-4-fluoro-3-methyl-benzonitrile
To a solution of diisopropylamine (474 mL, 3.35 mol) in anhydrous THF (5.8 L) at
-5 °C under a nitrogen atmosphere is added dropwise 2.5 M n-butyllithium in hexanes (1.24
L, 3.10 mol) over 3 h and the resulting mixture is stirred at -5 °C for one additional hour.
The LDA solution is added dropwise to a solution of 2-chloro-4-fluoro-benzonitrile (400 g,
2.58 mol) in anhydrous THF (5.8 L) at -70 °C over 6 h and then stirred at -70 °C overnight.
lodomethane (643 mL, 10.32 mol) is added dropwise over 2.5 h and the temperature is raised
to -5 °C for 17 h. Saturated aqueous ammonium chloride (3 L) is added. The solution is
diluted with water (3.5 L) and extracted with diethyl ether ( x 2 L). The organic phases are
separated, combined, dried over anhydrous sodium sulfate, filtered, and concentrated to
afford a black solid. The solid is purified through a silica gel pad eluting with
EtOAc/hexanes (1/40) to obtain the title compound (323 g, 74%). 1H NMR (300 MHz,
CDCls) d 7.08 (dd, J = 8.6, 8.6 Hz, 1H), 7.54 (dd, J = 8.6, 5.6 Hz, 1H), 2.36 (d, J = 2.4 Hz,
3H).
Preparation 2
2-chloro-3-ethyl-4-fluoro-benzonitrile
The title compound is prepared by essentially following the procedure described in
Preparation 1, using 2-chloro-4-fluoro-benzonitrile (12.2 g, 78.4 mmol), and iodoethane
(18.4 g, 9.43 mL, 118 mmol). The crude product is purified on silica gel using 15-50%
dichloromethane/hexanes to give the title compound as shiny white crystals (4.06 g, 28%).
1H-NMR (400 MHz, CDC13) d 7.54 (dd, J= 5.6, 8.6 Hz, 1H), 7.07 (t, j= 8.6 Hz, 1H), 2.85
(qd, J= 7.5, 2.3 Hz, 2H), 1.19 (t, j= 7.5 Hz, 3H).
Preparation 3
1-methyl-6-oxabicyclo[3 .1.0]hexane
A solution of 1-methylcyclopentene (25 mL, 0.24 mol) in dichloromethane (770 mL)
is cooled to 5 °C under nitrogen. MCPBA (87.5 g, 0.36 mol, 1.5 eq, 71%> wt) is added in
portions and the mixture is stirred at room temperature overnight. The reaction mixture is
filtered through a pad of diatomaceous earth. The filtrate is washed with aqueous saturated
sodium bicarbonate (500 mL) and 10% aqueous sodium thiosulfate (100 mL). The organic
portion is concentrated under reduced pressure while keeping the water bath temperature
below 20 °C to obtain the title compound (24 g, 99%). 1H NMR (400 MHz, CDC13) d 3.42
(s, 1H), 1.81-1.99 (m, 2H), 1.38-1.65 (m, 4H), 1.42 (s, 3H). GC-MS m/z 98 (M+) .
Preparation 4
trans-2-Amino- 1-methyl-cyclopentanol
relative
In a glass pressure vessel, a solution of l-methyl-6-oxabicyclo[3.1.0]hexane (25 g,
0.25 mol), ammonium hydroxide (50 mL, 0.36 mmol), water (50 mL), and ethanol (100 mL)
is heated at 90 °C for 4 h. The reaction mixture is concentrated and the residue is
coevaporated twice with isopropanol (100 mL) to obtain the title compound (28.4 g) that is
up to 45% pure by NMR. GC-MS m/z 115 (M+) . The crude material is used in the next step
(Example 1) without additional purification.
Preparation 5
-(Dibenzylamino)cyclopentanol
solute
To a solution of (lR,2S)-2-aminocyclopentanol hydrochloride (9.3 g, 67.6 mmol) and
potassium carbonate (28.02 g, 203 mmol) in acetone (675 mL) and water (48 mL) is added
benzyl bromide (16.1 mL, 135 mmol) in a single portion and the mixture refluxed overnight.
The heat is removed and the reaction is concentrated under reduced pressure. The residue is
diluted with aqueous 1M HCl and washed with ether. The aqueous layer is made alkaline
with sodium hydroxide and extracted with EtOAc. The organic portion is dried over sodium
sulfate, filtered, and concentrated under reduced pressure to afford the title compound as a
yellow oil (16.98 g, 89%). ES/MS m/z 282 (M+l).
Preparation 6
(2S)-2-(Dibenzylamino)cyclopentanone
To a solution of oxalyl chloride (6.28 mL, 72.4 mmol) in dichloromethane (75 mL) at
-60 °C under nitrogen is added a solution of DMSO (10.7 mL, 151 mmol) in
dichloromethane (75 mL) dropwise and stirred at -60 °C for 15 min. (lR,2S)-2-
(dibenzylamino)cyclopentanol (17.0 g, 60 mmol) in dichloromethane (75 mL) is added and
the reaction is stirred at -60 °C for 30 min. TEA (46 mL, 330 mmol) is added and the
reaction is allowed to warm to room temperature and stirred for 1 h. Water is added (100
mL) and the reaction is stirred overnight. The dichloromethane layer is separated, dried over
anhydrous sodium sulfate, filtered, and concentrated under reduced pressure to afford the title
compound as an orange oil (13.96 g, 83%). ES/MS m/z 280 (M+l).
Preparation 7
-(Dibenzylamino)- 1-methyl-cyclopentanol (enantioenriched)
solute
To a solution of (2S)-2-(dibenzylamino)cyclopentanone (8.3 lg, 29.7 mmol) in diethyl
ether (149 mL) at -78 °C is added methyl magnesium bromide (29.7 mL, 89.1 mmol, 3 M in
diethyl ether) slowly. The mixture is stirred at -78 °C for 4 h and then the reaction is
allowed to warm to room temperature. Water is added to the reaction, resulting in an
emulsion. Aqueous 1M hydrochloric acid is added to break up the emulsion while keeping
the aqueous phase basic. The aqueous phase is extracted twice with EtOAc. The combined
organic portions are dried over sodium sulfate, filtered, and concentrated under reduced
pressure. The resulting residue is purified by silica gel chromatography (10%
EtOAc/hexanes) to obtain the product. The material is dissolved in 1M hydrochloric acid
and extracted four times with EtOAc. The combined organic layers are dried over sodium
sulfate, filtered, and concentrated under reduced pressure to afford the title compound as an
orange solid (3.49 g, 40%). ES/MS m/z 296 (M+l).
Preparation 8
(lR,2S)-2-Amino-l -methyl-cyclopentanol (enantioenriched)
absolute
Palladium black (1.617 g), MeOH (150 mL), and (lR,2S)-2-(dibenzylamino)-lmethyl-
cyclopentanol (3.49 g, 11.8 mmol) are combined in a Parr bottle and hydrogenated at
room temperature overnight at 50-60 psi. No change is observed by ES/MS and additional
palladium black (0.51 g) is added and the hydrogenation continued for 6 h at 30 °C/60 psi.
There is no apparent change. The reaction is filtered and resubmitted to hydrogenation with
fresh palladium black (1.04 g) in MeOH. After 20 h, ES/MS still shows starting material
with no product observed. The mixture was filtered and concentrated. The material is
resubmitted to hydrogenation in MeOH (100 mL) using palladium black ( 1.02 g) for 24 h at
30 °C/60 psi. There is no change in the progress of the reaction. The hydrogenation is
continued, heating at 60 °C at 45-60 psi for about 52 h. Starting material is still present by
GC-MS. The mixture is filtered and concentrated. The resulting material is resubmitted to
hydrogenation using palladium black (1.57 g) in MeOH (100 mL) at 30 °C/60 psi for 24 h.
ES/MS provides evidence of removal of one benzyl group with a small amount of starting
material still present. 20% Palladium hydroxide on carbon (0.41 g) is added and the
hydrogenation is continued at 30 °C/60 psi for 20 h. ES/MS shows no starting material, but
also no product peak is observed. The reaction mixture is filtered and concentrated. The
resulting material is resubmitted to hydrogenation using fresh palladium black ( 1.20 g) in
MeOH (100 mL) at 30 °C/60 psi for 23 h. ES/MS still shows no formation of product. The
hydrogenation is continued with heating at 40 °C for 24 h. There is no change by ES/MS.
20% Palladium hydroxide on carbon (2.05 g) is added and the hydrogenation is continued at
room temperature/60 psi for 67 h. The reaction is filtered and concentrated down. (A small
aliquot (74 mg) is hydrogenated with ruthenium (IV) oxide (104 mg) in t-butanol (25 mL) at
60 °C/60 psi overnight. This results in reduction of the benzene ring without deprotection as
shown by ES/MS.) The resulting material is resubmitted to hydrogenation using 20%>
palladium hydroxide on carbon (1.01 g) in MeOH (100 mL) at 40 °C/50-60 psi for 2 1 h. On
ES/MS there is a small amount of product at 116 (M+l) and a significant peak at 206 (M+l)
for mono-benzylated intermediate. Palladium black ( 1.01 g) is added and the hydrogenation
continued at 30 °C/60 psi for 23 h. ES/MS does not show any starting material or
intermediate with peak 116 (M+l) and a potential impurity at 158. The reaction mixture is
filtered through diatomaceous earth and concentrated under reduced pressure to obtain the
crude title compound as a tan oil ( 1.61g, quantitative). The material is used without further
purification in the next step (Example 2) and is later found to be partially racemized. ES/MS
m/z 116 (M+l). 1H NMR (400 MHz, DMSO- ) d 7.84-7.85 (m, 1H), 5.1 1 (s, 1H), 3.03-
3.05 (m, 1H), 1.92-1.94 (m, 1H), 1.75-1.76 (m, 1H), 1.49-1.51 (m, 1H), 1.21 (s, 3H).
Alternate preparation 1 of 2-amino-l-methyl-cyclopentanol
(Preparations 9 - 12)
Preparation 9
-Butyl N-[-2-hydroxycyclopentyl] carbamate
relative
To a solution of trans-2-aminocyclopentanol hydrochloride (100 g, 726.7 mmol), in MeOH
(1.45 L) at room temperature under nitrogen , is added sodium carbonate (77 g, 726.7 mmol)
and di-t r t-butyl dicarbonate (182 mL, 835.7 mmol). The mixture is stirred overnight. The
mixture is filtered over a paper filter and methanol is evaporated. The resulting residue is
diluted with water and stirred for 30 min to give an off-white solid which is collected by
filtration. The solid is dried under vacuum to yield the title compound as a pale cream solid
(172.4 g, 89%). 1H-NMR (300 MHz, DMSO-d ) d 6.72 (d, 1H, NH), 4.61 (br s, 1H), 3.76
(m, 1H), 3.48 (m, 1H), 1.66-1.96 (m, 2H), 1.48-1.64 (m, 2H), 1.21-1.44 (m, 2H), 1.38 (s,
9H).
Preparation 10
N-(2-oxocyclopentyl)carbamate
2,2,6, 6-Tetramethylpiperidine-N-oxide (2.2 g, 14.2 mmol) and potassium bromide
(8.5 g, 7 1 mmol) are added to a solution of racemic trans-tert-hvXy\ N-[2-
hydroxycyclopentyl] carbamate (75 g, 283 mmol) in dichloromethane (285 mL). The mixture
is cooled to 5 °C with stirring. A freshly prepared ice cooled (5 °C) sodium hypochlorite
aqueous solution (766 mL, 566 mmol, pH adjusted to 7.5-8 by addition of 10 g of solid
potassium carbonate) is added with stirring to the reaction mixture while keeping the
temperature below 5 °C. The mixture is stirred at 5 °C for an additional 30 min. The
reaction mixture is diluted with saturated aqueous sodium chloride solution (150 mL). The
organic layer is separated and evaporated. The oily red residue is purified over a silica gel
pad, eluting with EtOAc/hexanes (1/3) to obtain the title compound as a cream colored solid
(43 g, 76%). 1H-NMR (300 MHz, DMSO-d ) d 6.99 (d, 1H, NH), 3.76 (q, 1H), 1.63-2.31 (m,
6H), 1.37 (s, 9H).
Preparation 11
fert-Butyl-2-[hydroxy-2-methyl-cyclopentyl]carbamate
A solution of tert-butyl N-(2-oxocyclopentyl)carbamate (racemic) (25 g, 125.5 mmol)
in diethyl ether (250 mL) is cooled to - 5 °C. Methylmagnesium bromide (125 mL,
375 mmol, 3 M in diethyl ether) is added, keeping the temperature at 0 °C. The reaction is
vigorously stirred and warmed to 22 °C over 2 h and then is allowed to warm to room
temperature overnight. The reaction mixture is cooled to 5 °C and quenched by the addition
of a cooled (5 °C) saturated solution of ammonium chloride (150 mL). The mixture is
warmed to room temperature. The phases are separated and the aqueous phase is extracted
with MTBE (3 150 mL). The combined organic portions are dried over sodium sulfate,
filtered, and concentrated under reduced pressure to obtain the title compound (26.4 g, 78%)
as crude material which is used without further purification.
Preparation 12
2-Amino- 1-methyl-cyclopentanol, hydrochloride
To a solution of t r t-butyl-2-hydroxy-2-methyl-cyclopentylcarbamate (25 g, 104.5
mmol) in dichloromethane (210 mL) is added hydrogen chloride in dioxane (156 mL, 6 mol,
4 M) and the reaction is stirred at room temperature for 3 h. The solvent is evaporated and
the resulting material is dried under vacuum to a constant weight to obtain the title compound
(20.4 g) as a dark brown oil which is used in the next step without further purification. GCMS
115.1 (M+); GC-MS analysis shows a cis/trans mixture in about a 3/2 ratio.
Second alternate preparation of 2-amino-l-methyl-cyclopentanol
(Preparations 13 - 18)
Preparation 13
[(lS,2S)-2-azidocyclopentoxy]-trimethyl-silane
absolute
Cz ' -1,2-epoxycyclopentane ( 11.0 g, 131 mmol) is treated with (lR,2R)-(-)-l,2-
cyclohexanediamino-N,N'-bis(3,5-di -t-butylsalicylidene)cobalt (II) (1.58 g, 2.62 mmol). The
mixture is stirred for 5 min at room temperature, treated with azidotrimethylsilane (20.9 mL,
18.1 g, 157 mmol), and heated to 50 °C for 16 h. The reaction is diluted with EtOAc,
hexanes, and diethyl ether, followed by addition of diatomaceous earth. The mixture is
filtered through a pad of diatomaceous earth which is then rinsed with diethyl ether and
hexanes. The filtrate is concentrated to give the crude product as a black oil. The crude
material is purified on silica gel (660 g, 0-2% EtOAc/hexanes, observed on TLC with
KMn0 4 staining) to give the title compound as a pale yellow oil 15.98 g (61%). 1H-NMR
(400 MHz, CDCls) d 4.00-3.96 (m, 1H), 3.65-3.61 (m, 1H), 2.05-1.99 (m, 1H), 1.93-1.89 (m,
1H), 1.80-1.75 (m, 2H), 1.58-1.53 (m, 2H), 0.13 (s, 9H).
Preparation 14
tert- y N-[(l S,2S)-2-trimethylsilyloxycyclopentyl]carbamate
A solution of [(lS,2S)-2-azidocyclopentoxy]-trimethyl-silane (15.4 g, 77.6 mmol) in
EtOH (141 mL) is treated with 10% palladium on carbon (1.82 g, 1.71 mmol) and
hydrogenated (60 psi) overnight at room temperature. The reaction mixture is filtered
through diatomaceous earth and rinsed with EtOH (50 mL). The filtrate is concentrated in
vacuo and dissolved in acetone (81 mL). Water (81 mL) and sodium carbonate (8.17 g,
77. 1 mmol) are added. The mixture is cooled to 0 °C and then treated with di-tbutyldicarbonate
(18.6 g, 85.3 mmol). The reaction is stirred for 72 h at room temperature
and then concentrated in vacuo to remove the acetone. The mixture is extracted with EtOAc
(3 150 mL). The combined organic extracts are dried over sodium sulfate, filtered, and
concentrated to give the title compound as a yellow oil (15.5 g, 73%). GC-MS m/z 156 (MNHBoc)
+, 202 (M-Si(Me 3))+.
Preparation 15
t r t-Butyl N-[(l S,2S)-2-hydroxycyclopentyl]carbamate
absolute
ter t-Butyl N-[(lS,2S)-2-trimethylsilyloxycyclopentyl]carbamate (15.5 g, 56.7 mmol)
and tetrabutylammonium fluoride (85.0 mL, 85.0 mmol) in THF ( 113 mL) are stirred at room
temperature for 1 h. Water (50 mL) is added and the mixture is concentrated in vacuo to
remove the THF. The resulting mixture is extracted with EtOAc (3 75 mL). The
combined organic portions are washed with brine (2 x 30 mL), dried over sodium sulfate,
filtered, and concentrated to give 14.7 g of crude product as a yellow oil. The material is
purified on silica gel (330 g) using 25% EtOAc/hexanes to give the title compound as a white
solid (10.25 g, 90%). LC-ES/MS m/z 224 (M+Na).
Preparation 16
tert-Butyl N-[(l S)-2-oxocyclopentyl]carbamate
absolute
A mixture of oxalyl chloride (6.47 mL, 74.5 mmol) in THF (166 mL) is cooled to
-72 °C under nitrogen and treated dropwise with DMSO (10.59 mL, 149.1 mmol). The
mixture is stirred for 5 min, whereupon t rt-butyl (lS,2S)-2-hydroxycyclopentylcarbamate
(10.0 g, 49.7 mmol) is added. Stirring is continued at -75 °C for 45 min. Triethylamine
(37.4 mL, 268.3 mmol) is added slowly keeping the temperature below -68 °C. After the
addition is complete the reaction is allowed to warm slowly to room temperature overnight.
The reaction is combined with the reaction mixture from a pilot reaction (200 mg scale)
completed earlier. Water (100 mL) is added and the reaction is concentrated in vacuo to
remove THF. The mixture is extracted with EtOAc (3 150 mL). The combined organic
portions are dried over sodium sulfate, filtered, and concentrated to give 12.41 g of crude
product as a yellow oil. The material is purified on silica gel (330 g, 10-40%
EtOAc/hexanes) to give the title compound (9.17 g, 93%). 1H-NMR (400 MHz, CDC13) d
5.04-5.02 (m, 1H), 3.98-3.96 (m, 1H), 2.65-2.63 (m, 1H), 2.44-2.39 (m, 1H), 2.21-2.1 1 (m,
1H), 2.04 (s, 1H), 1.89-1.85 (m, 1H), 1.66-1.59 (m, 1H), 1.44 (s, 9H). GC-MS m/z 199 (M+) .
[a] 2 = +96.9° (c 1.0, CHC13) [literature (Aube, J.; Wolfe, M.S.; Yantiss, R.K.; Cook, S.M.;
Takusagawa, F. Synthetic Communications 1992, 22, 3003-3012) [a] 25 = +125° (c 0.2,
CHC13)].
Preparation 17
t rt-Butyl N-[(l S)-2-hydroxy-2-methyl-cyclopentyl] carbamate
To a solution of t r t-butyl N-[(lS)-2-oxocyclopentyl]carbamate (9.04 g, 45.4 mmol)
in diethyl ether (227 mL) at 0 °C under nitrogen is added methylmagnesium bromide (37.8
mL, 113.4 mmol, 3.0 M in diethyl ether) dropwise. The reaction is warmed to room
temperature and stirred for 2 h. An aliquot is worked up and analyzed by NMR to show that
the reaction looks complete. The reaction was carefully quenched with saturated aqueous
ammonium chloride (10 mL) and water (100 mL). EtOAc (200 mL) and 1N HC1 (50 mL)
are added to dissolve a white precipitate. The layers are separated and the aqueous portion
extracted with EtOAc (2 x 200 mL). The combined organic portions are dried over sodium
sulfate, filtered, and concentrated to give a yellow oil (9.48 g). Analysis by GC-MS and
NMR showed about 20% starting material still remaining. The material (7.25 g) is
redissolved in diethyl ether (227 mL) and cooled to 0 °C. Methylmagnesium bromide
(13.2 mL, 39.5 mmol) is added portionwise, keeping the temperature below 7 °C. The
reaction is warmed to room temperature and another portion of methylmagnesium bromide
(15.1 mL, 45.4 mmol) is added portionwise. The reaction is allowed to stir at room
temperature overnight at which time GC-MS shows 5% starting material remaining. The
reaction is quenched carefully with saturated aqueous ammonium chloride (20 mL). Water
(200 mL) and 5 N HCI (20 mL) are added and the mixture extracted with EtOAc
(3 300 mL). The combined organic portions are dried over sodium sulfate, filtered, and
concentrated to give a dark amber oil (6.97 g). GC-MS m/z 158 (M-tBu)+. GC-MS analysis
shows a cis/trans mixture in a 68:32 ratio. Use as is without further purification.
Preparation 18
(2S)-2-amino- 1-methyl-cyclopentanol hydrochloride
A solution of tert-butyl N-[(lS)-2-hydroxy-2-methyl-cyclopentyl]carbamate (mixture
of cis and trans diastereomers) (6.66 g, 30.9 mmol), 4 M HCI in dioxane (46.4 mL,
185.6 mmol), and dichloromethane (62 mL) is stirred at room temperature for 1 h. The
reaction is concentrated in vacuo, and then redissolved in MeOH and reconcentrated to give
the title compound as a brown oil (5.09 g). LC-ES/MS m/z 116 (M+l).
Preparation 19
-1-methyl-cyclohexanol, hydrochloride
Methyl magnesium bromide (4.7 mL, 14,1 mmol, 3 M in diethyl ether) is added
dropwise to a stirring solution of t rt-butyl-2-oxo-cyclohexylcarbamate (1.00 g, 4.69 mmo
in diethyl ether (50 mL) at -78 °C. After the addition is complete, the reaction is allowed to
warm to room temperature and stirred for 22 h. The reaction is quenched with dilute
hydrochloric acid and extracted two times with EtOAc. The organic portions are combined
and dried over sodium sulfate, filtered, and concentrated in vacuo to yield the crude title
compound ( 1.02 g) as a probable mixture of t rt-butyl N-(2-hydroxy-2-methylcyclohexyl)
carbamate, ES-MS m/z 252 (M+Na), and the cyclized compound, 7a-methyl-
3,3a,4,5,6,7-hexahydro-l,3-benzoxazol-2-one. ES-MS m/z 156 (M+1). The crude material
was used as is without further purification.
The material is dissolved in 1,4-dioxane (15 mL) and treated with 12 M hydrochloric
acid (1.1 mL) with stirring at room temperature for 3 days. The reaction is concentrated in
vacuo, diluted with MeOH, and reconcentrated and dried in vacuo to yield the title compound
(730 mg, 94% for 2 steps). ES-MS m/z 130.1 (M+1).
Preparation 20
3,6-Dihydro-2H-pyran
4-Bromotetrahydropyran (20 g, 121 mmol) and 5 N sodium hydroxide (30 mL) are
stirred and heated at 90 °C for 18 h. The mixture is cooled to room temperature and the
organic layer is separated from the aqueous. The organic layer, containing product only, is
poured into a pre-weighed flask containing sodium sulfate for drying, which yields the title
compound as a pale yellow oil (9.99 g, 98%). The title compound is stored over sodium
sulfate as volatility prevents any filtering, rinsing, and concentration in vacuo. 1H NMR
(400 MHz, DMSO-de) d 5.78-5.74 (m, 1H), 5.69-5.66 (m, 1H), 3.96-3.94 (m, 2H), 3.61 (t, J=
5.5 Hz, 2H), 2.01-1.99 (m, 2H).
Preparation 21
4,7-Dioxabicyclo[4. 1.0]heptane
MCPBA (29.28 g, 130.6 mmol, 77 wt/wt%) is added to a solution of 3,6-dihydro-2Hpyran
(9.99 g, 118.8 mmol) in dichloromethane (100 mL) at 0 °C and stirred for 1 h before
allowing to warm to room temperature and stirring for 18 h. A saturated aqueous solution of
sodium bicarbonate is carefully added and the mixture stirred vigorously. The organic layer
is separated from the aqueous, dried over sodium sulfate, filtered, and concentrated in vacuo
to yield the title compound (9.7 g, 82%). 1H NMR (400 MHz, DMSO-d ) d 3.84 (dd, J= 2.7,
13.4 Hz, 1H), 3.74-3.70 (m, 1H), 3.38-3.26 (m, 3H), 3.10-3.09 (m, 1H), 1.87-1.82 (m, 2H).
Preparation 22
trans-4-Azidotetrahydropyran-3-ol
relative
Sodium azide (50.4 g, 775 mmol) is added to a stirring solution of 4,7-
dioxabicyclo[4.1.0]heptane (9.7 g, 96.9 mmol) and ammonium chloride (23.0 g, 426 mmol)
in methanol (484 mL) and water (97 mL), and heated to 65 °C under nitrogen for 18 h. The
mixture is cooled to room temperature and water (200 mL) is added. The methanol is
removed in vacuo and the remaining aqueous layer is extracted with EtOAc (3 ) . The
organic portions are combined, dried over sodium sulfate, filtered, and concentrated in vacuo
to yield the title compound as a tan oil (5.63 g, 41%). 1H NMR (400 MHz, DMSO-d ) d
5.40-5.33 (m, 1H), 3.78-3.74 (m, 2H), 3.40-3.32 (m, 3H), 2.97-2.90 (m, 1H), 1.82-1.77 (m,
1H), 1.46-1.41 (m, 1H).
Preparation 23
-4-Aminotetrahydropyran-
OH relative
A mixture of trans-4-azidotetrahydropyran-3-ol (5.63 g, 39.3 mmol) and 10% Pd/C
(2.09 g, 1.97 mmol) in methanol (157 mL) is hydrogenated (45 psi) at room temperature for
18 h. After filtering the mixture through diatomaceous earth, the filtrate is concentrated in
vacuo to yield the title product as a tan semisolid (4.8 g, quantitative). ES-MS m/z 118.1
(M+l).
Preparation 24
trans-4-Azidotetrahydrofuran-3-ol
ovA relative
The title compound is prepared by essentially following the procedure as described
for Preparation 22, using 3,4-epoxytetrahydrofuran. The crude product is obtained as a pale
yellow oil (10,5 g). GC-MS m/z 129 (M+) .
Preparation 25
trans-tert- y N-[4-hydroxytetrahydrofuran-3 -yl]carbamate
relative
A solution of tra/?s-4-azidotetrahydrofuran-3-ol (9.55 g, 74.0 mmol) in ethanol
(247 mL) is treated with 10% palladium on carbon (787 mg, 0.370 mmol) and stirred for 16 h
at room temperature under 60 psi of hydrogen. The reaction mixture is filtered through
diatomaceous earth and rinsed with EtOH (100 mL). The filtrate is concentrated in vacuo
and dissolved in acetone (77 mL). Water (77 mL) and sodium carbonate (7.79 g, 73.5 mmol)
are added and the mixture is cooled to 0 °C before adding di-t-butyldicarbonate (17.8 g,
81.3 mmol). The reaction is stirred for 72 h at room temperature and then concentrated in
vacuo. The mixture is extracted with EtOAc (3 300 mL), and the combined organic
extracts dried over magnesium sulfate, filtered, and concentrated to give the title compound
as a white solid (10.71 g, 71%). 1H NMR (400 MHz, CDC13) d 4.82-4.81 (m, 1H), 4.28 (d,
J= 0.3 Hz, 1H), 4.10-4.02 (m, 2H), 3.96-3.95 (m, 1H), 3.69 (dd, J= 3.0, 10.0 Hz, 1H), 3.61
(dd, J= 3.0, 9.5 Hz, 1H), 3.29-3.27 (m, 1H), 1.48-1.44 (m, 9H).
Preparation 26
tert-Butyl N-(4-oxotetrahydrofuran-3 -yl)carbamate
A mixture of oxalyl chloride (3.20 mL, 36.9 mmol) in THF (137 mL) is cooled to
-78 °C under nitrogen and treated dropwise with DMSO (5.24 mL, 73.8 mmol). The mixture
is stirred for 20 min at -78 °C, whereupon trans-tert-b ty N-[4-hydroxytetrahydrofuran-3-
yljcarbamate (5.00 g, 24.6 mmol) is added. Stirring at -78 °C is continued for 1 h.
Triethylamine (18.5 mL, 133 mmol) is added and the reaction is warmed to room
temperature. The reaction is stirred for 16 h, then water (100 mL) is added and the reaction
is concentrated in vacuo to remove THF. The mixture is extracted with EtOAc (3 70 mL),
the combined organics dried over magnesium sulfate, filtered, and concentrated to give 6.4 g
of crude product as an orange oil. The crude product is purified on silica gel (220 g, 15-30%
EtOAc/hexanes) to give the title compound as a yellow oil (2.20 g, 44%>). GC-MS m/z 201
(M)+,143 (M-t-Bu)+.
Preparation 27 and 28
cis-tert-Butyl N-[4-hydroxy-4-methyl-tetrahydrofuran-3-yl]carbamate and trans-tert-Butyl
N-[4-hydroxy-4-methyl-tetrahydrofuran-3-yl]carbamate
relative relative
To a solution of tert-butyl N-(4-oxotetrahydrofuran-3-yl)carbamate (2.12 g, 10.5
mmol) in diethyl ether (53 mL) at 0 °C under nitrogen is added methylmagnesium bromide
(10.5 mL, 31.6 mmol, 3.0 M in diethyl ether) portionwise. The reaction is warmed to room
temperature and stirred for 16 h. The reaction is carefully quenched with saturated aqueous
ammonium chloride (10 mL) and water (100 mL). The reaction mixture is extracted with
EtOAc (3 70 mL), the combined organic portions dried over MgS0 4, filtered, and
concentrated to give crude product as a yellow oil (2.1 1 g). The material is purified on silica
gel [80 g, 10-30% EtOAc/(l:l dichloromethane/hexanes)]. The first-eluting diastereomer is
racemic t rt-butyl N-[(3S,4S)-4-hydroxy-4-methyl-tetrahydrofuran-3-yl]carbamate (and
enantiomer) obtained as a colorless oil (1.04 g, 45%). Cis stereochemistry assigned on the
basis of NMR of Example 10. LC-ES/MS m/z 240 (M+Na). The second-eluting product is
racemic tert-butyl N-[(3S,4R)-4-hydroxy-4-methyl-tetrahydrofuran-3-yl]carbamate (and
enantiomer) obtained as a white solid (460 mg, 20%). Trans stereochemistry based on NMR
of Example 11. LC-ES/MS m/z 240 (M+Na).
Preparation 29
trans-4-Amino-3-methyl-tetrahydrofuran-3 -ol hydrochloride
relative
A solution of racemic tert-butyl N-[(3S,4R)-4-hydroxy-4-methyl-tetrahydrofuran-3-
yljcarbamate (450 mg, 2.07 mmol), 4.0 M HCI in dioxane (5.2 mL, 2 1 mmol), dioxane (5
mL), and methanol (0.8 mL) is stirred at room temperature for 16 h. The reaction mixture is
concentrated in vacuo. The resulting residue is slurried in dichloromethane and concentrated
in vacuo, followed by dissolution in MeOH and concentration in vacuo to give the crude title
compound as a tan oil (366 mg, quantitative). LC-ES/MS m/z 118 (M+l).
Preparation 30
cis-4-Amino-3-methyl-tetrahydrofuran-3 -ol hydrochloride
relative
The title compound is prepared by essentially following the procedure as described in
Preparation 29, using cis tert-hvXy\ N-[(3S,4S)-4-hydroxy-4-methyl-tetrahydrofuran-3-
yl]carbamate (racemic). 1H-NMR (400 MHz, DMSO-d ) d 8.18-8.17 (m, 2H), 3.99-3.94 (m,
1H), 3.68-3.64 (m, 2H), 3.54 (d, J=8.35 Hz, 1H), 3.41-3.39 (m, 1H), 1.31 (s, 3H).
Preparation 31
(3S,4R)-4-Trimethylsilyloxytetrahydrofuran-3 -amine
bsolute
A mixture of [(3R,4S)-4-azidotetrahydrofuran-3-yl]oxy-trimethyl-silane (870 mg,
4.2 mmol; prepared according to the exact procedure found in Jacobsen, E.N.; Larrow, J.F.;
Schaus, S.E. J . Org. Chem. 1997, 62, 4197-4199; except that commercially available
(lR,2R)-(-)-l,2-cyclohexanediamino-N,N'-bis(3,5-di-t-butylsalicylidene)cobalt (II) is used as
catalyst), 10% palladium on carbon (230 mg, 216 mihoΐ), and THF (22 mL) is stirred at room
temperature under hydrogen (60 psi) for 16 h. The reaction is filtered through a pad of
diatomaceous earth and the pad is rinsed with THF (50 mL). The filtrate is concentrated in
vacuo to give the title compound as a brown oil (825 mg, quantitative). LC-ES/MS m/z 176
(M+l).
Preparation 32
(3R,4S)-4-Trimethylsilyloxytetrahydrofuran-3-amine
absolute
The title compound is prepared by essentially following the procedure described in
Preparation 3 1 using [(3S,4R)-4-azidotetrahydrofuran-3-yl]oxy-trimethyl-silane (9.34 g,
46.4 mmol; prepared in opposing stereochemical configuration compared to the procedure
found in Jacobsen, E.N.; Larrow, J.F.; Schaus, S.E. J . Org. Chem. 1997, 62, 4197-4199;
except using commercially available (lS,2S)-(+)-l,2-cyclohexanediamino-N,N'-bis(3,5-di-tbutylsalicylidene)
cobalt (II) as catalyst) to provide a colorless oil (7.55 g, 93%). LC-ES/MS
m/z 176 (M+l).
Preparation 33
(3S,4S)-4 -(t rt-Butyl(dimethyl)silyl)oxytetrahydrofuran-3-ol
A mixture of (3S,4S)-tetrahydrofuran-3,4-diol (9.35 g, 89.8 mmol), tbutyldimethylchlorosilane
(14.9 g, 98.8 mmol), TEA (13.8 mL, 98.8 mmol), and
dichloromethane (100 mL) is stirred at room temperature for 4 days. The reaction is
concentrated in vacuo and purified on silica gel (330 g, 35-80% EtOAc/hexanes, observed on
TLC using KMn0 4 staining) to give 3.66 g (19%>) of the title compound as a light yellow oil.
GC-MS m/z 161 (M-tBu)+.
Preparation 34
[(3S,4S)-4 -(t r t-Butyl(dimethyl)silyl)oxytetrahydrofuran-3-yl] methanesulfonate
Under nitrogen, a solution of (3S,4S)-4 -(t rt-butyl(dimethyl)silyl)oxytetrahydrofuran-
3-ol (3.30 g, 15.1 mmol), 2,6-lutidine (0.200 mL, 1.72 mmol), and diisopropylethylamine
(2.90 mL, 16.6 mmol) in dichloromethane (50 mL) is cooled to -10 °C and treated slowly
with methanesulfonyl chloride ( 1.23 mL, 15.9 mmol). The reaction is warmed up to room
temperature and stirred for 16 h. A second addition of methanesulfonyl chloride (0.351 mL,
4.53 mmol) is added and the reaction is stirred at room temperature for a further 16 h. The
reaction is shaken with dilute aqueous HC1 and dichloromethane. The layers are separated
and the organic portion is dried over Na2S0 4, filtered, and concentrated in vacuo to give the
title compound as a pale yellow oil (3.99 g, 89%). GC-MS m/z 239 (M-tBu)+.
Preparation 35
[(3R,4R)-4-Azidotetrahydrofuran-3-yl]oxy -t rt-butyl-dimethyl-silane
absolute
[(3S,4S)-4-(rer t-butyl(dimethyl)silyl)oxytetrahydrofuran-3-yl] methanesulfonate
(3.00 g, 10.1 mmol) is dissolved in DMF (50 mL). Sodium azide (1.32 g, 20.2 mmol) is
added and the reaction is heated to 60 °C for 72 h. Tetra-n-butylammonium iodide (0.400 g,
1.08 mmol) is added and the temperature is raised to 120 °C for 14 days. Water is added and
the product is extracted into EtOAc. The organic layer is washed with water a second time
and then dried over magnesium sulfate, filtered, and concentrated to give 2.9 g of crude
product as a pale yellow oil. The crude product is purified on silica gel (120 g, 2-20%
EtOAc/hexanes, observed on TLC with KMn0 4 staining) to give the title compound as a
colorless oil (1.3 g, 53%). GC-MS m/z 186 (M-tBu)+.
Preparation 36
(3R,4R)-4-(fer t-Butyl(dimethyl)silyl)oxytetrahydrofuran-3-amine
NH2
absolute
A mixture of [(3R,4R)-4-azidotetrahydrofuran-3-yl]oxy -t rt-butyl-dimethyl-silane
(1.27 g, 5.22 mmol) and 10% palladium on carbon (25 mg, 0.023 mmol) in ethanol (20 mL)
is stirred at room temperature under a hydrogen balloon for 16 h. The reaction is filtered
through a pad of diatomaceous earth and the filtrate is concentrated in vacuo to give the title
compound as a colorless oil (1.0 g, 88%). LC-ES/MS m/z 218 (M+l).
Preparation 37
2-Methylcyclopent-2-en- 1-ol
Sodium borohydride (8.86 g, 234 mmol) is added to a solution of 2-methyl-2-
cyclopenten-l-one (20.7 g, 215 mmol) in diethyl ether (430 mL) at -30 °C under nitrogen.
The reaction is warmed up to 0 °C and treated with methanol (9.48 mL, 234 mmol). The
reaction is warmed up to room temperature and stirred for 16 h. The reaction is treated with
methanol (9.48 mL, 234 mmol), and then 1 h later treated again with methanol (9.48 mL, 234
mmol). The reaction is stirred for 72 h at room temperature, treated with brine (200 mL) and
extracted into diethyl ether (3 300 mL). The combined organic portions are dried over
magnesium sulfate, filtered, and concentrated in vacuo using a 30 °C water bath to afford the
title compound as a colorless oil (24.2 g, quantitative). GC-MS m/z 98 (M+) .
Preparation 38
t rt-Butyl-(2-methylcyclopent-2-en- 1-yl)oxy-diphenyl-silane
TBDPS- 0
To a solution of 2-methylcyclopent-2-en-l-ol (23.06 g, 235.0 mmol), lH-imidazole
(32.0 g, 470 mmol) and N,N-dimethyl-4-pyridinamine (5.74 g, 47.0 mmol) in
dichloromethane (470 mL) at room temperature is added t rt-butylchlorodiphenylsilane
(90.41 g, 328.94 mmol) over 15 min. After stirring the reaction mixture at room temperature
for 16 h, water (300 mL) is added and the layers are separated. The aqueous layer is
extracted with dichloromethane (2 x 200 mL). The combined organic portions are dried over
sodium sulfate, filtered, and concentrated to give the crude product (108 g) as a colorless oil.
The crude product is purified in 20 g batches on 330 g silica gel using 0-20%
dichloromethane/hexane (product observed on TLC using KMn04 staining) to give the title
compound as a colorless oil (25.3 g, 32%). 1H-NMR (400 MHz, CDC13) d 7.72-7.69 (m,
4H), 7.44-7.41 (m, 6H), 5.44-5.41 (m, 1H), 4.72-4.70 (m, 1H), 2.33-2.29 (m, 1H), 2.06-2.01
(m, 2H), 1.74-1.69 (m, 1H), 1.66-1.65 (m, 3H), 1.09 (s, 9H).
Preparation 39 and Preparation 40
r /-t rt-Butyl-[[(lS,4S,5S)-5-methyl-6-oxabicyclo[3.1.0]hexan-4-yl]oxy]-diphenyl-silane,
Diastereomer 1 and re/-tert-Butyl-[[(lR,4S,5R)-5-methyl-6-oxabicyclo[3.1.0]hexan-4-
yl]oxy]-diphenyl-silane, Diastereomer 2
relative relative
MCPBA (77% wt, 5.03 g, 22.5 mmol, 0.8 eq) is added to a 0 °C solution of tertbutyl-(
2-methylcyclopent-2-en-l-yl)oxy-diphenyl-silane (9.45 g, 28.1 mmol) in
dichloromethane (94 mL) and saturated aqueous sodium bicarbonate (28 mL). The reaction
is stirred for 16 h at room temperature and then treated with more MCPBA (77 % wt, 2.52 g,
11.2 mmol, 0.4 equiv) and saturated aqueous sodium bicarbonate (56 mL). After stirring for
2 h at room temperature the reaction is quenched by adding saturated aqueous a2S0 3
solution and stirring for 30 min at room temperature. The reaction is extracted with
dichloromethane (3 70 mL). The combined organic portions are dried over sodium sulfate,
filtered, and concentrated. The crude product is purified on silica gel (330 g, 30-60%
dichloromethane/hexanes). The first eluting product from the silica gel column is rel-tertbutyl-[[(
lS,4S,5S)-5-methyl-6-oxabicyclo[3.1.0]hexan-4-yl]oxy]-diphenyl-silane (mixture of
enantiomers, relative stereochemistry determined by NMR analysis) (3.03 g, 31%, colorless
oil). 1H-NMR (400 MHz, CDC13) d 7.68-7.64 (m, 4H), 7.45-7.42 (m, 6H), 4.21-4.20 (m,
1H), 3.35 (s, 1H), 1.93-1.88 (m, 2H), 1.45 (s, 3H), 1.43-1.40 (m, 2H), 1.08 (s, 9H). LCES/
MS m/z 353 (M+1). The second-eluting product from the silica gel column is rel-tertbutyl-[[(
lR,4S,5R)-5-methyl-6-oxabicyclo[3. 1.0]hexan-4-yl]oxy]-diphenyl-silane (mixture
of enantiomers) (5.82 g, 59%, milky white oil). 1H-NMR (400 MHz, CDC13) d 7.73-7.69 (m,
4H), 7.46-7.42 (m, 6H), 4.03 (t, J= 7.9 Hz, 1H), 3.1 1 (s, 1H), 1.90-1.85 (m, 1H), 1.48-1.43
(m, 3H), 1.30 (s, 3H), 1.08 (s, 9H). LC-ES/MS m/z 353 (M+1).
Preparation 41
re/-(lS,2R,5S)-2-Azido-5 -(t r t-butyl(diphenyl)silyl)oxy-l-methyl-cyclopentanol
TBDPS relative
A mixture of rel -t r t-butyl-[[(lS,4S,5S)-5-methyl-6-oxabicyclo[3.1.0]hexan-4-
yl]oxy]-diphenyl-silane (enantiomeric mixture) (1.0 g, 2.8 mmoles), sodium azide (782 mg,
11.9 mmol), and DMF (10 mL) is stirred at 60 °C for 16 h. Lithium perchlorate (604 mg,
5.7 mmol) and additional sodium azide (931 mg, 14.2 mmol) are added and the reaction is
heated to 90 °C for 72 h, then cooled to room temperature. The reaction is treated with water
(50 mL) and extracted with EtOAc (3 70 mL). The combined organic portions are dried
over magnesium sulfate, filtered, and concentrated to afford the title compound as a pale
yellow oil (2.5 1 g). The material is carried forward crude without further purification or
characterization.
Preparation 42
re/-(lS,2R,5R)-2-Azido-5 -(t rt-butyl(diphenyl)silyl)oxy-l-methyl-cyclopentanol
The title compound is prepared by essentially following the procedure as described in
Preparation 4 1 using re/-tert-butyl-[[(lR,4S,5R)-5-methyl-6-oxabicyclo[3.1.0]hexan-4-
yl]oxy]-diphenyl-silane (enantiomeric mixture), except that the reaction is heated to 90 °C
for 48 h and the addition of lithium perchlorate and the second addition of sodium azide are
omitted.
Preparation 43
rel-{\ S,2R,5 S)-2-Amino-5-(t r t-butyl(diphenyl)silyl)oxy- 1-methyl-cyclopentanol
A mixture of re/-(lS,2R,5S)-2-azido-5 -(t r t-butyl(diphenyl)silyl)oxy-l-methylcyclopentanol
(2.28 g, 5.76 mmol, enantiomeric mixture) and 10% palladium on carbon
(61 mg) in ethanol (29 mL) is hydrogenated (60 psi) at room temperature for 16 h. The
reaction is filtered through a pad of diatomaceous earth and rinsed with EtOH (50 mL). The
filtrate is concentrated in vacuo, dissolved in dichloromethane (10 mL), and concentrated in
vacuo. The crude product is purified on silica gel (120 g, 1-6% (2 M ammonia in
methanol/dichloromethane) to afford the title compound as an opaque yellow oil (419 mg,
20%). LC-ES/MS m/z 353 (M+l).
Preparation 44
rel-{\ S,2R,5R)-2-Amino-5 -(t rt-butyl(diphenyl)silyl)oxy- 1-methyl-cyclopentanol
The title compound is prepared by essentially following the procedure describe in
Preparation 43, using re/-(lS,2R,5R)-2-azido-5 -(t rt-butyl(diphenyl)silyl)oxy-l-methylcyclopentanol
to provide the product as a pale yellow oil. LC-ES/MS m/z 370 (M+l).
Example 1
t -2-Chloro-4-[[2-hydroxy-2-methyl-cyclopentyl] amino]-3-methyl-benzonitrile, Isomer 2
bsolute
In a glass pressure vessel, a mixture of trans-2-amino-l-methyl-cyclopentanol
(8.75 g, 53 mmol, 1.5 eq), 2-chloro-4-fluoro-3-methyl-benzonitrile (6 g, 35.4 mmol) and
lithium carbonate (7.84 g, 106 mmol) in DMSO (72 mL) and water (7.2 mL) is degassed for
15 min by bubbling nitrogen through the mixture. The vessel is sealed and heated at 130 °C
for 36 h. After cooling to room temperature, the mixture is quenched over ice/water
(700 mL) at 5 °C (internal temperature) with stirring. After 15 min, the initially sticky solid
turns into a cream solid that is collected by filtration and washed with cold water. The solid
is stirred over EtOAc (100 mL) for 30 min and filtered through a pad of diatomaceous earth.
The EtOAc filtrate is concentrated to afford 15 g of a yellow solid. The material is purified
by silica gel chromatography using dichloromethane to elute impurities and 10%
EtOAc/dichloromethane to elute final product to obtain the racemic title compound (9.2 g,
98%). 1H NMR (400 MHz, DMSO-d ) d 7.48 (d, 1H), 6.90 (d, 1H), 5.51 (d, 1H), 4.66 (s,
1H), 3.65-3.74 (m, 1H), 2.21 (s, 3H), 2.01-2.13 (m, 1H), 1.50-1.78 (m, 5H), 1.07 (s, 3H).
LC-ES/MS m/z ( 5C1/ C1) 265.2/267.1 (M+l). The compound is dissolved in MeOH (70
mL). The enantiomers are separated in 2 1 mg injections by supercritical fluid
chromatography on two CHIRALPAK® AD-H columns (2 x 25 cm, 5 mih) stringed in
series. Mobile phase: 20% isopropanol/carbon dioxide. Flow rate: 65 mL/min. Detection:
215 nm. Each run is 6.48 min. The first eluting peak is obtained as Isomer 1 and the second
eluting peak is obtained as the title compound, Isomer 2 (4.13 g, 100% enantiomeric excess).
The enantiomeric excess is determined by SFC on a CHIRALPAK® AD-H (4.6 x 100 mm,
5 mih) column using 20% isopropanol/carbon dioxide. Flow rate: 2.5 mL/min. Detection:
215 nm. Isomer 1 TR = 2.53 min. Isomer 2 (title compound) TR = 3.06 min.
The compound of Example 1 can also be named or referred to as 2-chloro-4-
[[( 1R,2R)-2-hydroxy-2-methyl-cyclopentyl] amino]-3-methyl-benzonitrile.
Example 1A (Alternate procedure)
2-Chloro-4-[[(lR,2R)-2-hydroxy-2-methyl-cyclopentyl]amino]-3-methyl-benzonitrile
The reaction below is carried out in six batches in parallel.
A mixture of trans-2-amino-l-methyl-cyclopentanol (34.93 g, 212.3 mmol), 2-chloro-
4-fluoro-3 -methyl-benzonitrile (30 g, 176.9 mmol), lithium carbonate (26.14 g, 353.8 mmol),
DMSO (270 mL), water (30 mL) in a 420 mL pressure reactor is degassed for 15 min by
bubbling nitrogen, sealed, and heated with vigorous stirring at 130 °C for 48 h. After cooling
to room temperature, three of the batches are poured over water (9 L) and MTBE ( 1 L),
stirred for 30 min, filtered through diatomaceous earth and transferred to a separation funnel.
The organic layer is separated and the aqueous phase is washed twice with MTBE (2 x 1L).
The organic layers are combined, dried over sodium sulfate, filtered and concentrated in
vacuo. The workup is repeated for the remaining three batches and all the lots are combined
to isolate the desired crude product (400 g). The material is purified on silica gel, eluting
with 0 to 10% EtOAc/dichloromethane to obtain pure racemic title compound {trans
diastereomer) (280 g, 99%). The compound is dissolved at a concentration of 10.3 mg/mL in
25% isopropanol/75% heptanes mobile phase. The enantiomers are separated in portions of
1.16 g ( 113 mL) per injection by preparative HPLC on a CHIRALPAK® AD-H column
( 11 x 35 cm, 20 mih) using a steady state recycle (SSR) method (10.2 g/h throughput).
Mobile phase: 25% isopropanol/heptane. Flow rate: 850 mL/min. Detection: 290 nm. The
first eluting peak is obtained as Isomer 1 (>98% enantiomeric excess) and the second eluting
peak is obtained as the title compound, Isomer 2 (137 g, 97.7% enantiomeric excess). The
enantiomeric excess is determined by HPLC on a CHIRALPAK® AD-H (4.6 x 150 mm,
5 mih) column using 25% isopropanol/heptane. Flow rate: 0.6 mL/min. Detection: 270 nm.
Isomer 1 TR = 6.7 min. The desired isomer is the 2nd eluting under these chiral HPLC
conditions. Isomer 2 (title compound) TR = 7.9 min.
Example IB
Recrystillization and single crystal x-ray for determination of absolute stereochemistry
2-Chloro-4-[[(lR,2R)-2-hydroxy-2-methyl-cyclopentyl]amino]-3-methyl-benzonitrile
2-Chloro-4-[[(lR,2R)-2-hydroxy-2-methyl-cyclopentyl]amino]-3-methyl-benzonitrile
(21.62 g, 81.66 mmol) is placed in a round bottom flask provided with a heating mantel, an
internal thermometer, and a stir bar. Acetone (33 mL) is added and the slurry is stirred and
heated to 50 °C. At this temperature, the yellowish solid goes into solution completely. The
solution is heated to 60 °C. Heptane is added slowly using an addition funnel. After adding
75 mL, every drop of solvent creates a cloudiness that disappears almost instantly upon
stirring at 60 °C. After additional heptanes (50 mL) the cloudiness takes longer to disappear
since the solution is getting saturated. The solution stays cloudy and the addition of heptane
is stopped. The temperature is raised to 62 °C and acetone (5 mL) is added which makes the
solution completely clear again. Heptane (100 mL) is added dropwise making the solution
cloudy again. The temperature is raised to 67 °C and acetone is distilled and collected in a
Dean-Stark apparatus. The slurry is allowed to cool to room temperature gradually and left
to sit for 18 h. The resulting white solid is filtered and placed on high vacuum. After 4 h on
high vacuum a significant amount of acetone is observed to be present by NMR. Additional
time on high vacuum did not remove the acetone. The material is slurried in hexane for 30
min, filtered, and placed on high vacuum again to give the final compound as a white solid
(18.1 g). LC-ES/MS m/z 265.0 (M+l).
Determination of absolute stereochemistry: The compound has a pronounced
tendency to form solvated structures with nearly every solvent in which it has significant
solubility. As proof of the molecule's absolute stereochemistry, crystals were formed using a
chiral solvent such that the known chirality of its stereocenter could be related to the chirality
of the unknown stereocenter of the drug molecule. This served as one source of
determination of the absolute stereochemistry. A second method used for its determination
was accomplished by refinement of the absolute structure parameter. The anomalous
dispersion, in large part due to the "heavier" chlorine atom was sufficiently significant to
conclude the absolute stereochemistry of the compound directly, as the parameter refined to a
value of 0.054(1 1). Both methods are commonly accepted methods for determination of
chirality of unknown stereocenters of organic molecules by X-ray crystallography and
afforded consistent results. The structure studied crystallized as a "hemi" solvate of S-(-)-
methyl lactate as described herein, having a ratio of two drug molecules for one solvent
molecule. 2-Chloro-4-[[(lR,2R)-2-hydroxy-2-methyl-cyclopentyl]amino]-3-methylbenzonitrile
(35 mg, taken from the 18.1 g lot described above) is dissolved in S-(-)-methyl
lactate (500 m ) . The sample vial is placed "lid-less" into a larger container, a 100 mL
Pyrex® bottle that contains n-pentane, and the larger bottle is capped. Vapor diffusion is
allowed to occur overnight, whereby the more volatile n-pentane diffused into the solution of
2-chloro-4-[[(l R,2R)-2-hydroxy-2-methyl-cyclopentyl]amino]-3-methyl-benzonitrile and S-
(-)methyl lactate, effecting the growth of single crystals. The crystals were harvested by
decanting off the excess solution. One of the large crystals was isolated and analyzed by
single crystal X-ray diffraction. The data collection and results from the single crystal
structure determination of this solvated form had the following characteristics.
A single crystal is mounted on a thin glass fiber at 100(2)°K. Data are collected using
a CuKa radiation source (l = 1.54178 A) and a Bruker D8 based 3-circle goniometer
diffractometer equipped with a SMART 6000CCD area detector (Bruker-AXS. Madison,
Wisconsin, USA). Cell refinement and data reduction are performed using the SAINT
program V7.68a (Sheldrick, G. M. SHELXS86. Acta Cryst. (1990) A46, 467-473). The unit
cell is indexed, having monoclinic parameters of a = 7.5457(2) A, b = 17.1858(6) A,
c = 12.3017(4) A and b = 97.6870(10) ° . The cell volume of crystal structure was 1580.93(9)
A^. The calculated density of the molecule is 1.331 g/cm at 100 °K. The structure is solved
by direct methods (Sheldrick, G. M. SHELXS86. Acta Cryst. (1990) A46, 467-473). All nonhydrogen
atomic parameters were independently refined. The space group choice of P2(l)
was confirmed by successful convergence of the full-matrix least-squares refinement on F2
(Sheldrick, G. M. (1993). SHELXS93). Program for crystal structure refinement. Institute
fur anorg chemie, Gottingen, Germany) with a final goodness of fit of 1.038. The final
residual factor, Ri, is 0.0344 and wR2 is 0.089. The largest difference peak and hole after the
final refinement cycle are 0.239 and -0.298 (eA-3), respectively. The absolute
stereochemistry is determined by refinement of the absolute structure parameter to 0.054(1 1),
indicating the stereochemistry of the molecule is as depicted (1R,2R).
X-ray Powder Diffraction data (XRPD) characterization of anhydrous forms
The XRD patterns of the crystals are obtained on a Bruker D4 Endeavor X-ray
powder diffractometer, equipped with a CuKa source l = 1.54056 A) and a Vantec detector,
operating at 35 kV and 50 mA and with 1mm divergence and receiving slits and a 0.1mm
detector slit. Each sample is scanned between 4 and 40° in 2Q. The dry powder is packed
into recessed top-loading sample holder and a smooth surface is obtained using a glass slide.
The crystal form diffraction patterns are collected at ambient temperature and relative
humidity.
It is well known in the crystallography art that, for any given crystal form, the relative
intensities of the diffraction peaks may vary due to preferred orientation resulting from
factors such as crystal morphology and habit. Where the effects of preferred orientation are
present, peak intensities are altered, but the characteristic peak positions of the polymorph
are unchanged. See, e.g., The United States Pharmacopeia #23, National Formulary #18,
pages 1843-1844, 1995. Furthermore, it is also well known in the crystallography art that for
any given crystal form the angular peak positions may vary slightly. For example, peak
positions can shift due to a variation in the temperature or humidity at which a sample is
analyzed, sample displacement, or the presence or absence of an internal standard. In the
present case, a peak position variability of ± 0.1 in 2Qwill take into account these potential
variations without hindering the unequivocal identification of the indicated crystal form.
Example 1C
2-Chloro-4-[[(lR,2R)-2-hydroxy-2-methyl-cyclopentyl]amino]-3-methyl-benzonitrile
crystalline Form 1
2-Chloro-4- [[( 1R,2R)-2-hydroxy-2-methyl-cyclopentyl] amino]-3-methyl-benzonitrile
(430 mg) is dissolved into acetone ( 1 mL) to which heptane (5 mL) is added. The mixture is
stirred at 60 °C. The mixture is then allowed to concentrate to give a thick white slurry and
heptane (3 mL) is incorporated as the concentration at 60 °C continues. The material is
vacuum filtered to give 308 mg (72%) and further dried under vacuum at 70 °C overnight.
Confirmation of a crystal form may be made based on any unique combination of
distinguishing peaks (in units of ° 2Q), typically the more prominent peaks. Thus, a prepared
sample of 2-chloro-4-[[(lR,2R)-2-hydroxy-2-methyl-cyclopentyl]amino]-3-methylbenzonitrile
crystalline Form 1 is characterized by an XRD pattern using CuKa radiation as
having diffraction peaks (2-theta values) as described in Table 1 below, and in particular
having peaks at 9.18 in combination with one or more of the peaks selected from the group
consisting of 14.87, 17.97, and 18.46; with a tolerance for the diffraction angles of 0.1
degrees.
Table 1
Example ID
2-Chloro-4-[[(lR,2R)-2-hydroxy-2-methyl-cyclopentyl]amino]-3-methyl-benzonitrile
crystalline Form 2
The material recrystillized in Example IB is used to characterize Form 2.
Confirmation of a crystal form may be made based on any unique combination of
distinguishing peaks (in units of ° 2Q), typically the more prominent peaks. Thus, a prepared
sample of 2-chloro-4-[[(lR,2R)-2-hydroxy-2-methyl-cyclopentyl]amino]-3-methylbenzonitrile
crystalline form 2 is characterized by an XRD pattern using CuKa radiation as
having diffraction peaks (2-theta values) as described in Table 2 below, and in particular
having peaks at 20.45 in combination with one or more of the peaks selected from the group
consisting of 17.77, 16.15, and 12.59; with a tolerance for the diffraction angles of 0.1
degrees.
Table 2
X-ray powder diffraction peaks of
Example ID
Peak Angle (2-theta °) Intensity (%)
1 14.52 17
2 16.15 49
3 17.77 72
4 20.45 100
5 21.77 23
6 25.19 33
7 26.19 29
8 26.93 13
9 30.07 22
10 30.96 29
11 32.65 11
12 35.91 32
13 37.36 14
Example IE
2-Chloro-4-[[(lR,2R)-2-hydroxy-2-methyl-cyclopentyl]amino]-3-methyl-benzonitrile
crystalline ethanol solvate
2-Chloro-4-[[(lR,2R)-2-hydroxy-2-methyl-cyclopentyl]amino]-3-methyl-benzonitrile
(104 mg) is weighed into a small sample vial. Ethanol (0.50 mL) is added. The sample is
allowed to stir over the weekend. The material isolated is then characterized by X-ray
diffraction. The pattern is collected quickly to minimize phase conversion, using the same
settings as before, albeit with a larger step size of 0.017 degrees two-theta and 0.1 seconds
per step.
Confirmation of a crystal form may be made based on any unique combination of
distinguishing peaks (in units of ° 2Q), typically the more prominent peaks. Thus, a prepared
sample of 2-chloro-4-[[(lR,2R)-2-hydroxy-2-methyl-cyclopentyl]amino]-3-methylbenzonitrile
crystalline ethanol solvate crystal form is characterized by an XRD pattern using
CuKa radiation as having diffraction peaks (2-theta values) as described in Table 3 below,
and in particular having peaks at 7.00 in combination with one or more of the peaks selected
from the group consisting of 17.26, 23.34, and 12.30; with a tolerance for the diffraction
angles of 0.2 degrees.
Table 3
Example IF
2-Chloro-4-[[(lR,2R)-2-hydroxy-2-methyl-cyclopentyl]amino]-3-methyl-benzonitrile
crystalline isopropanol solvate
2-Chloro-4-[[(lR,2R)-2-hydroxy-2-methyl-cyclopentyl]amino]-3-methyl-benzonitrile
( 114 mg) is weighed into a small sample vial. Isopropanol (0.50 mL) is added. The sample
is allowed to stir over the weekend. The material isolated is then characterized by X-ray
diffraction.
Confirmation of a crystal form may be made based on any unique combination of
distinguishing peaks (in units of ° 2Q), typically the more prominent peaks. Thus, a prepared
sample of 2-chloro-4-[[(lR,2R)-2-hydroxy-2-methyl-cyclopentyl]amino]-3-methylbenzonitrile
crystalline isopropanol solvate crystal form is characterized by an X-ray powder
diffraction pattern using CuKa radiation as having diffraction peaks (2-theta values) as
described in Table 4 below, and in particular having peaks at 7.07 in combination with one
or more of the peaks selected from the group consisting of 6.93, 17.12, and 23.13; with a
tolerance for the diffraction angles of 0.2 degrees.
Table 4
Example 1G
Large scale recrystillization
2-Chloro-4-[[(lR,2R)-2-hydroxy-2-methyl-cyclopentyl]amino]-3-methyl-benzonitrile
In a 3L 3-necked round bottom flask, 2-chloro-4-[[(lR,2R)-2-hydroxy-2-methylcyclopentyl]
amino]-3-methyl-benzonitrile (131.4 g, 496.3 mmol) in acetone (200 mL) is
heated to 50 °C until all the solids dissolve. The temperature is increased to 60 °C and
heptane (approximately 1.35 L) is added slowly using an addition funnel. The temperature is
raised to 65 °C and acetone (approximately 15 mL) is distilled and collected with a Dean-
Stark trap. After 1 h the temperature is raised to 67 °C. The solution is seeded with
crystalline 2-chloro-4-[[(lR,2R)-2-hydroxy-2-methyl-cyclopentyl]amino]-3-methylbenzonitrile
( 1 g) and acetone (approximately 80 mL) is distilled. Seed crystals can be
obtained from Example IB, or generated from the solids obtained in Example 1 or 1A, or can
be obtained using other methods common to one skilled in the art, such as recystallization of
a small aliquot. After l h the heat is turned off and the slurry is left to cool down to room
temperature slowly. The white solids are collected by filtration and left under vacuum
overnight to obtain 116.0 g of product. Additional product (5.6 g) was collected by filtration
from the mother liquor. In a 3L flask, a slurry of the 116.0 g of product in hexanes ( 1.5L) is
seeded with 2-chloro-4-[[(lR,2R)-2-hydroxy-2-methyl-cyclopentyl]amino]-3-methylbenzonitrile
(approximately 2 g) and stirred for 4 h. The white solid is collected by filtration
and is left under a nitrogen stream over 48 hours. Additional product (2.6 g) precipitates
from the mother liquor and is collected by filtration. A total amount of 109.7 g of 2-chloro-
4-[[(1R,2R)-2-hydroxy-2-methyl-cyclopentyl] amino]-3-methyl-benzonitrile is isolated.
1H NMR (400 MHz, DMSO-d ) d 7.47 (d, 1H), 6.90 (d, 1H), 5.48 (d, 1H), 4.64 (s, 1H), 3.65-
3.74 (m, 1H), 2.19 (s, 3H), 2.01-2.13 (m, 1H), 1.50-1.78 (m, 5H), 1.03 (s, 3H). LC-ES/MS
m/z ( 5C1/ C1) 265.2/267.2 (M+l). [a] = +20.2° (c 1.0, EtOH).
Example 2
2-Chloro-4-[[(lS,2R)-2-hydroxy-2-methyl-cyclopentyl]amino]-3-methyl-benzonitrile
bsolute
In a sealed pressure vessel, a mixture of 2-chloro-4-fluoro-3-methyl-benzonitrile ( 1.2
g, 7.08 mmol), (lR,2S)-2-amino-l-methyl-cyclopentanol (1.63 g, 14.2 mmol) and lithium
carbonate (1.10 g, 14.9 mmol) in DMSO (14.4 mL) and water (1.4 mL) is heated at 130 °C
overnight. After allowing the reaction to cool to room temperature, the mixture is diluted
with EtOAc and washed twice with 1N hydrochloric acid. The organic phase is
concentrated under reduced pressure and purified using radial chromatography eluting with
EtOAc/hexanes (20 to 50% EtOAc/hexanes gradient). The resulting residue is repurified
using radial chromatography with 1% methanol/dichloromethane. The isolated product is
recrystallized with ether/hexanes, collected by filtration, and dried under reduced pressure to
yield the title compound as a white solid (450 mg, 24%). A second crop (84 mg) is also
isolated. LC-ES/MS m/z ( 5C1/ C1) 265/267 (M+l). 1H NMR (400 MHz, DMSO-d ) d 1.16
(s, 3H), 1.71-1.73 (m, 5H), 2.12-2.13 (m, 1H), 2.14 (s, 3H), 3.46-3.50 (m, 1H), 4.93 (s, 1H),
5.26-5.30 (m, 1H), 6.63 (d, J= 8.8 Hz, 1H), 7.47 (d, J= 8.6 Hz, 1H). Chiral HPLC showed
the material had an enantiomeric excess of 67%. The enantiomeric excess is determined by
SFC on a CHIRALPAK® AS-H (4.6 x 150 mm, 5 m i) column using 20% ethanol/carbon
dioxide. Flow rate: 5 mL/min. Detection: 225 nm. Isomer 1 (title compound):
T R = 1.39 min; Isomer 2 : TR = 1.99 min. The absolute stereochemistry of Isomer 1 (1S,2R)
is known by correlation of retentions times with Isomer 1 and Isomer 2 as described in
Example 3.
The enantioenriched material (534 mg) is dissolved in methanol (5.5 mL) and
purified in 500 m injections by SFC on a CHIRALPAK® AS-H (2.1 x 25 cm, 5 mih)
column using 20% ethanol/carbon dioxide. Flow rate: 70 mL/min. Detection: 225 nm. The
title compound is isolated as the first eluting peak, Isomer 1 (326 mg) in 99% enantiomeric
excess. The enantiomeric excess is determined by SFC as described above.
Alternate procedure (Example 2A & 2B)
Example 2A
c -2-Chloro-4-[[2-hydroxy-2-methyl-cyclopentyl]amino]-3-methyl-benzonitrile
2-Chloro-4-fluoro-3-methyl-benzonitrile (12.4 g, 73.2 mmol) is added to a solution of
freshly prepared racemic 2-amino-l-methyl-cyclopentanol, hydrochloride (20.4 g) in DMSO
(145 mL) in a pressure reactor vessel. Lithium carbonate (15.5 g, 209 mmol) and water
(14.5 mL) are added. The mixture is stirred and degassed with nitrogen for 10 min. The
reactor is sealed and the reaction stirred at 130 °C for 28 h. The mixture is cooled to room
temperature and diluted with water ( 1 L) and MTBE (150 mL). The mixture is stirred for
10 min at room temperature and filtered through a pad of diatomaceous earth. The organic
layer is separated and the aqueous layer extracted with MTBE (2 x 100 mL). The organic
portions are combined, dried over sodium sulfate, filtered, and evaporated to afford crude
material. The material is purified using silica gel chromatography eluting first with 100%
methylene chloride to obtain the cw-2-chloro-4-[[2-hydroxy-2-methyl-cyclopentyl]amino]-3-
methyl-benzonitrile compound (5.6 g, 20%). 1H NMR (300 MHz, DMSO-d ) d 7.47 (d, J=
8.6 Hz, 1H), 6.63 (d, J= 8.8 Hz, 1H), 5.26-5.30 (m, 1H), 4.93 (s, 1H), 3.46-3.50 (m, 1H),
2.14 (s, 3H), 2.12-2.13 (m, 1H), 1.71-1.73 (m, 5H), 1.16 (s, 3H). LC-ES/MS m/z 265.2
(M+l).
After isolation of the cis isomer, elution is continued using a mixture of methylene
chloride/EtOAc (9/1) to afford (3.6 g, 12%) of the trarcs-2-chloro-4-[[2-hydroxy-2-methylcyclopentyl]
amino]-3-methyl-benzonitrile. 1H NMR (300 MHz, DMSO-d ) d 7.48 (d, 1H),
6.90 (d, 1H), 5.51 (d, 1H), 4.66 (s, 1H), 3.65-3.74 (m, 1H), 2.21 (s, 1H), 2.01-2.13 (m, 1H),
1.50-1.78 (m, 5H), 1.07 (s, 3H). LC-ES/MS m/z 265.2 (M+l).
Example 2B
2-Chloro-4-[[(lS,2R)-2-hydroxy-2-methyl-cyclopentyl]amino]-3-methyl-benzonitrile
C -2-chloro-4-[[2-hydroxy-2-methyl-cyclopentyl]amino]-3-methyl-benzonitrile
(9.5 g) is purified in 70 mg injections by supercritical fluid chromatography on two
CHIRALPAK® Chiralpak AS-H columns (2 x 25 cm, 5 um) stringed in series eluting with
20% ethanol/carbon. Flow rate: 65 mL/min. Detection: 215 nm. Each run is 4.5 min. The
first eluting peak provides the title compound as Isomer 1 (4.23 g, > 98% enantiomeric
excess). Isomer 1 (title compound): TR = 1.40 min; Isomer 2 : TR = 1.77 min. The absolute
stereochemistry of Isomer 1 (1S,2R) is known by correlation of retentions times with Isomer
1 and Isomer 2 as described in Example 3.
The material obtained from SFC purification is dissolved in MTBE (10 L/Kg) and
then treated with charcoal (200 mg) and silica gel ( 1 g). The mixture is stirred for 1 h and
then filtered through a pad of diatomaceous earth. The filtrates are collected and evaporated
to obtain the title compound (4.1 g) as a white solid. LC-ES/MS m/z 265.2 (M+1); 1H NMR
(400 MHz, DMSO- ) 1.16 (s, 3H), 1.73-1.71 (m, 5H), 2.13-2.12 (m, 1H), 2.14 (s, 3H),
3.50-3.46 (m, 1H), 4.93 (s, 1H), 5.30-5.26 (m, 1H), 6.63 (d, J= 8.8 Hz, 1H), 7.47 (d, J= 8.6
Hz, 1H); Chiral purity > 98% ee, Chiralpak AS-H, 20% EtOH/C0 2, 65 mL/min, 215 nm.
Example 3
2-Chloro-4-[[(lR,2S)-2-hydroxy-2-methyl-cyclopentyl]amino]-3-methyl-benzonitrile
2-Chloro-4- [[2-hydroxy-2-methyl-cyclopentyl]amino] -3-methyl-benzonitrile is
prepared essentially as described in Example 1 using 2-amino-l-methyl-cyclopentanol,
hydrochloride and 2-chloro-4-fluoro-3 -methyl-benzonitrile. The crude material was purified
using silica gel chromatography (25-55% EtOAc/hexane) to obtain Diastereomer 1 (0.54 g)
and Diastereomer 2 (1.56 g). Diastereomer 2 is assigned trans configuration based on cocrystal
with AR.
Diastereomer 1 (c -2-chloro-4- [[(2-hydroxy-2-methyl-cyclopentyl]amino] -3-methylbenzonitrile)
(500 mg) is dissolved in 5:1 methanol/dichloromethane (6 mL). The
enantiomers are separated in 750 injections by supercritical fluid chromatography on a
CHIRALPAK® AD-H column (2.1 x 25 cm). Mobile phase: 20% ethanol/carbon dioxide.
Flow rate: 70 mL/min. Detection: 280 nm. Each run is 3.1 min. The first eluting peak is
obtained as Isomer 1 (206 mg, 99% enantiomeric excess). The absolute stereochemistry of
Isomer 1 (1S,2R) is determined by X-ray of AR co-crystal.
The second eluting peak is obtained as the title compound (1R, 2S), Isomer 2 (256
mg, 99% enantiomeric excess). The enantiomeric excess is determined by SFC on a
CHIRALPAK® AD-H (2.1 x 25 cm, 5 mpi) column using 20% ethanol/carbon dioxide.
Flow rate: 5 mL/min. Detection: 225 nm. Isomer 1 TR = 1.37 min; Isomer 2 TR = 1.86 min.
LC-ES/MS m/z 264.8 (M+l).
Example 4 and Example 5
c -2-Chloro-4-[[2-hydroxy-2-methyl-cyclohexyl]amino]-3-methyl-benzonitrile
and trans-2-Chloro-4- [[2-hydroxy-2-methyl-cyclohexyl]amino] -3-methyl-benzonitrile
2-Chloro-4-[2-hydroxy-2-methyl-cyclopentyl]amino]-3-methyl-benzonitrile is
prepared essentially as described in Example 1 using 2-amino-l-methyl-cyclohexanol
hydrochloride and 2-chloro-4-fluoro-3 -methyl-benzonitrile. The crude material was purified
using silica gel chromatography (25-55% EtOAc/hexane) to obtain the first eluting
compound as Diastereomer 1 (cis) (482 mg). LC-ES/MS m/z 279 (M+l) and
The second eluting compound as Diastereomer 2 (trans) (101 mg). LC-ES/MS m/z 279
(M+l). Relative stereochemistry is assigned based on NMR of Example 6.
Examples 6 and 7
2-chloro-4-[[(lR,2S)-2-hydroxy-2-methyl-cyclohexyl]amino]-3-methyl-benzonitrile
(Enantiomer 1) and
2-chloro-4-[[(lS,2R)-2-hydroxy-2-methyl-cyclohexyl]amino]-3-methyl-benzonitrile
(Enantiomer 2)
absolute absolute
The enantiomeric mixture of czs-2-chloro-4-[[2-hydroxy-2-methylcyclohexyl]
amino]-3-methyl-benzonitrile (450 mg) is dissolved in 2:1:1
methanol/ethanol/dichloromethane (4 mL) and separated in 300 injections by
supercritical fluid chromatography on a CHIRALPAK® AD-H column (2.1 x 15 cm, 5 mih) .
Mobile phase: 20% ethanol/carbon dioxide. Flow rate: 70 mL/min. Detection: 225 nm.
The first eluting peak is obtained as Enantiomer 1 and the second eluting peak is obtained as
Enantiomer 2. The enantiomeric excess is determined by SFC on a CHIRALPAK® AD-H
(2.1 x 25 cm, 5 mih) column using 20% ethanol/carbon dioxide. Flow rate: 5 mL/min.
Detection: 225 nm.
Example 6, Enantiomer 1: 216 mg, TR = 1.44 min, 99% ee; LC-ES/MS m/z 279 (M+l); Cis
relative stereochemistry determined by NMR. 1H NMR (400 MHz, CDC13) d 1.10-1 .90 (m,
12H), 2.19 (s, 3H), 3.10-3.25 (m, 1H), 4.66 (d, 1H), 6.40 (d, 1H), 7.31 (d, 1H).
Example 7, Enantiomer 2 : 205 mg, TR = 1.83 min, 99% ee; LC-ES/MS m/z 279 (M+l).
Absolute stereochemistry (1S,2R) determined by X-ray with AR.
Example 8
2-chloro-3-ethyl-4-[[(lS,2R)-2-hydroxy-2-methyl-cyclopentyl]amino]benzonitrile
2-Chloro-3-ethyl-4-[[(lS)-2-hydroxy-2-methyl-cyclopentyl]amino]benzonitrile is
prepared essentially as described in Example 1 using (2S)-2-amino-l-methyl-cyclopentanol
hydrochloride (Preparation 18) and 2-chloro-3-ethyl-4-fluoro-benzonitrile. The crude
material (350 mg) is purified using silica gel chromatography (20-60% EtOAc/hexane) to
obtain Diastereomer 1 (cis) (82 mg) and Diastereomer 2 (trans) (29 mg).
Example 8, Diasteromer 1: LC-ES/MS m/z 279 (M+1). NMR analysis shows structure
consistent with cis diastereomer. 1H-NMR (400 MHz, CDC13) d 7.33 (d, J= 8.7 Hz, 1H),
6.45 (d, J= 8.8 Hz, 1H), 5.15-5.1 1 (m, 1H), 3.49-3.41 (m, 1H), 2.76-2.70 (m, 2H), 2.28-2.24
(m, 1H), 1.89-1.84 (m, 3H), 1.72-1.67 (m, 3H), 1.36 (s, 3H), 1.14 (t, J= 7.6 Hz, 3H). The
enantiomeric excess is determined by SFC on a CHIRALPAK® AS-H (2.1 x 25 cm) column
using 20% EtOH/carbon dioxide. Flow rate: 5 mL/min. Detection: 225 nm. 70% ee, 85%
@ TR = 1.24 min, 15% @ TR = 1.75 min.
Diasteromer 2 : LC-ES/MS m/z 279 (M+1). Chiral LC shows 60% ee.
The compounds in Table 5 below are prepared by essentially following the procedure as
described for Example 1, using trans-4-aminotetrahydropyran-3-ol (Preparation 23) and 2-
chloro-4-fluoro-3-methyl-benzonitrile or 2-chloro-3-ethyl-4-fluoro-benzonitrile.
Table 5
Example 10
c -2-Chloro-3 -ethyl-4- [[4-hydroxy-4-methyl-tetrahydrofuran-3 -yl]amino]benzonitrile
The title compound is prepared by essentially following the procedure as described in
Example 1, using czs-4-amino-3-methyl-tetrahydrofuran-3-ol hydrochloride (Preparation 30)
and 2-chloro-3-ethyl-4-fluoro-benzonitrile. NMR analysis in comparison with Example 1
and 2 indicates cis relative stereochemistry. 1H-NMR (400 MHz, CDC13) d 7.36-7.33 (m,
1H), 6.37 (d, J= 8.7 Hz, 1H), 5.30-5.25 (m, 1H), 4.30-4.26 (m, 1H), 3.87 (d, J= 9.9 Hz, 1H),
3.78-3.74 (m, 2H), 3.64-3.59 (m, IH), 2.76 (q, J= 7.6 Hz, 2H), 2.13 (s, IH), 1.44-1.43 (m,
3H), 1.16 (t, J= 7.6 Hz, 3H). LC-ES/MS m/z 281 (M+l).
Example 11
trans-2-Chloro-3-ethyl-4-[[4-hydroxy-4-methyl-tetrahydrofuran-3-yl]amino]benzonitrile
The title compound is prepared by essentially following the procedure as described in
Example 1, using trans-4-amino-3-methyl-tetrahydrofuran-3-ol hydrochloride (Preparation
29) and 2-chloro-3-ethyl-4-fluoro-benzonitrile. NMR analysis in comparison with Example
1 and 2 indicates trans relative stereochemistry. 1H-NMR (400 MHz, CDC13) d 7.36 (d, J=
8.6 Hz, IH), 6.71 (d, J= 8.8 Hz, IH), 4.45 (dd, J= 6.2, 9.6 Hz, IH), 4.27-4.24 (m, IH), 4.03-
3.98 (m, IH), 3.84 (d, J= 9.8 Hz, IH), 3.71 (d, J= 9.8 Hz, IH), 3.62 (dd, J= 4.1, 9.6 Hz, IH),
2.81-2.70 (m, 2H), 2.35-2.34 (m, IH), 1.32 (s, 3H), 1.13 (t, J= 7.6 Hz, 3H). LC-ES/MS m/z
281 (M+l).
Example 12
2-Chloro-4- [[(3R,4R)-4-hydroxytetrahydrofuran-3 -yl]amino] -3-methyl-benzonitrile
The title compound is prepared by essentially following the procedure as described in
Example 1 using (3R,4R)-4-(t rt-butyl(dimethyl)silyl)oxytetrahydrofuran-3-amine
(Preparation 36) and 2-chloro-4-fluoro-3-methyl-benzonitrile. The crude product is purified
on silica gel using 40-70% EtOAc/hexanes. The isolated product is dissolved in THF to
make a 0.5 M solution. TBAF (2.0 mL, 2 mmol, 1M solution in THF) is added and stirred at
room temperature for 16 h. The solution is concentrated in vacuo, EtOAc is added, and the
solution is washed with water (2x). The organic portion is dried over magnesium sulfate,
filtered, and concentrated. The residue is purified by reverse phase chromatography on
silica-bound CI8 using 15-95% acetonitrile/water + 0.1% formic acid. Fractions containing
the title compound are concentrated in vacuo to remove acetonitrile, then extracted with
EtOAc. The organics are dried over magnesium sulfate and concentrated in vacuo to give the
title compound as a white solid (134 mg, 19%). 1H-NMR (400 MHz, DMSO-d ) d 7.53 (d,
J= 8.7 Hz, 1H), 6.73 (d, J= 8.8 Hz, 1H), 5.60-5.56 (m, 1H), 5.53 (d, J= 4.9 Hz, 1H), 4.33-
4.29 (m, 1H), 4.05-3.99 (m, 2H), 3.92 (dd, J= 4.6, 9.6 Hz, 1H), 3.63 (dd, J= 2.4, 9.5 Hz, 1H),
3.53-3.50 (m, 1H), 2.19 (s, 3H). LC-ES/MS m/z 253 (M+1).
The Examples in Table 6 below are prepared by essentially following the procedure
described in Example 12 using the appropriate TMS or TBDMS-protected aminoalcohol and
2-chloro-4-fluoro-3-methyl-benzonitrile or 2-chloro-3-ethyl-4-fluoro-benzonitrile.
Table 6
4
2-Chloro-4-[[(3R,4S)-4-
253
14 hydroxytetrahydrofuran-3 -yl]amino] -3-
(M+1)
methyl-benzonitrile
"
'
absolute
0 H
2-Chloro-3-ethyl-4-[[(3R,4R)-4- 267
15 hydroxytetrahydrofuran-3 -
yl]amino]benzonitrile
(M+1)
Preparation 46
2-Chloro-3-methyl-4-[(3-oxotetrahydropyran-4-yl)amino]benzonitrile
To a solution of oxalyl chloride (1.22 mL, 14.1 mmol) in dichloromethane (15 mL) at
-60 °C is added dropwise a solution of dimethyl sulfoxide (2.08 mL, 29.3 mmol) in
dichloromethane (15 mL) and stirred at -60 °C for 15 min.
t r -2-chloro-4-[(3-hydroxytetrahydropyran-4-yl)amino]-3-methyl-benzonitrile (3.13 g,
11.7 mmol, Example 9) in dichloromethane (30 mL) is added to the solution and stirred at
-60 °C for 30 min. Triethylamine (9 mL, 64.5 mmol) is added and the mixture is warmed to
room temperature and stirred for 3 h. The mixture is diluted with EtOAc and washed twice
with 1N hydrochloric acid. The organic portion is dried over sodium sulfate, filtered, and
concentrated in vacuo to give the crude title compound as an orange semi-solid (2.53 g,
81%). LC-ES/MS m/z 265.2 (M+1).
The oxotetrahydropyran or oxotetrahydrofurans in Table 7 below, are prepared by
essentially following the procedure described in Preparation 46, using as starting material the
appropriate alcohol and proceeding with 1.2 to 1.5 eq oxalyl chloride, and 2.5 to 3 eq of
DMSO, at -60 to -75 °C in THF.
Table 7
Examples 16 and 17
2-chloro-4-[[(3S,4S)-4-hydroxy-4-methyl-tetrahydromran-3-yl]am
and 2-chloro-4-[ [(3S,4R)-4-hydroxy-4-methyl-tetrahydrofuran-3 -yljamino] -3-methylbenzonitrile
A solution of 2-chloro-3-methyl-4-[[(3S)-4-oxotetrahydrofuran-3-
yl]amino]benzonitrile (148 mg, 0.590 mmol) in THF (2.4 mL) at 0 °C is treated with
methylmagnesium bromide (0.49 mL, 1.50 mmol, 3 M in diethyl ether) dropwise under
nitrogen. The reaction is warmed up to room temperature and stirred for 16 h. The reaction
is quenched with saturated aqueous ammonium chloride (5 mL) and extracted with EtOAc
(3 40 mL). The combined organics are dried over magnesium sulfate, filtered, and
concentrated to give 143 mg of crude product. The crude product is purified on silica gel
(24 g, 5-80% EtOAc/hexanes) to give the title compounds.
Example 16, 3S, ^-isomer: First to elute from the column is the 3S, ^-isomer which is
isolated as a yellow film (25 mg, 16%). Its diastereomerism and thus absolute
stereochemistry is determined by NMR analysis. 1H-NMR (400 MHz, CDC13) d 7.35 (d, J=
8.6 Hz, IH), 6.37 (d, J= 8.6 Hz, IH), 5.10 (d, J= 7.0 Hz, IH), 4.28 (dd, J= 7.1, 9.0 Hz, IH),
3.88 (d, J= 9.9 Hz, IH), 3.77 (dt, J= 9.9, 5.6 Hz, 2H), 3.62 (dd, J= 7.0, 9.0 Hz, IH), 2.34-
2.30 (m, IH), 2.25 (s, 3H), 1.44 (s, 3H). LC-ES/MS m/z 267 (M+l).
Example 17, 3S,4R-isomQr: Second to elute from the column is the J^^-isomer which is
isolated as a tan film (48 mg, 30%). 1H-NMR (400 MHz, CDC13) d 7.40-7.38 (m, IH), 6.72-
6.70 (m, IH), 4.48-4.44 (m, IH), 4.14-4.13 (m, IH), 4.06-4.04 (m, IH), 3.86-3.83 (m, IH),
3.72 (d, J= 9.8 Hz, IH), 3.64-3.59 (m, IH), 2.23 (s, 3H), 2.14 (s, IH), 1.31 (s, 3H). LCES/
MS m/z 267 (M+l).
Examples 18 and 19
2-chloro-4-[[(3R,4R)-4-hydroxy-4-methyl-tetrahydrofuran-3-yl]amino]-3-methylbenzonitrile
and 2-chloro-4-[[(3R,4S)-4-hydroxy-4-methyl-tetrahydrofuran-3-yl]amino]-3-
methyl-benzonitrile
The title compounds are prepared by essentially following the procedure as described
for Examples 16 and 17, using 2-chloro-3-methyl-4-[[(3R)-4-oxotetrahydrofuran-3-
yl]amino]benzonitrile. The crude product is purified on silica gel (5-80% EtOAc/hexanes).
Example 18, 3R,4R-isomer: First isomer to elute from the column is the 3R,4R-isomer which
is isolated as a white solid (60 mg, 7%). Its diastereomerism and thus absolute
stereochemistry is determined by NMR analysis. 1H-NMR (400 MHz, CDC13) d 7.35 (d, J=
8.6 Hz, 1H), 6.37 (d, J= 8.6 Hz, 1H), 5.25-5.24 (m, 1H), 4.28 (dd, J= 7.1, 9.0 Hz, 1H), 3.88
(d, J= 9.9 Hz, 1H), 3.79-3.75 (m, 2H), 3.62 (dd, j= 6.9, 9.0 Hz, 1H), 2.26 (s, 3H), 1.44 (s,
3H). LC-ES/MS m/z 267 (M+l).
Example 19, 3R, ^-isomer: Second isomer to elute from the column is the 3R, ^-isomer
which is isolated as a white solid ( 115 mg, 13%). 1H-NMR (400 MHz, CDC13) d 7.38 (d, J=
8.6 Hz, 1H), 6.71 (d, J= 8.7 Hz, 1H), 4.45 (dd, J= 6.2, 9.6 Hz, 1H), 4.14-4.09 (m, 1H), 4.04-
3.99 (m, 1H), 3.84 (d, J= 9.9 Hz, 1H), 3.71 (d, J= 9.8 Hz, 1H), 3.63-3.60 (m, 1H), 2.23 (s,
3H), 2.04 (s, 1H), 1.31 (s, 3H). LC-ES/MS m/z 267 (M+l).
Examples 20 and 21
2-Chloro-4-[[(lS,2R,3S)-2,3-dihydroxy-2-methyl-cyclopentyl]amino]-3-methyl-benzonitrile
(Isomer 1) and 2-Chloro-4-[[(lR,2S,3R)-2,3-dihydroxy-2-methyl-cyclopentyl]amino]-3-
methyl-benzonitrile (Isomer 2)
olute
Isomer 1 lsomer 2
The TBDPS-protected title compound is prepared by essentially following the
procedure described in Example 1, using re/-(lS,2R,5R)-2-amino-5 -(t rtbutyl(
diphenyl)silyl)oxy-l-methyl-cyclopentanol (9.84 g, 26.62 mmol, Preparation 44) and
2-chloro-4-fluoro-3-methyl-benzonitrile (3.42 g, 20.17 mmol). A 0.2 M solution of the crude
product in THF is treated with TBAF (30.25 mL, 30.25 mmol, 1.0 M in THF) and stirred at
room temperature for 16 h. The mixture is treated with water, concentrated in vacuo and
extracted into EtOAc. The organic extracts are dried over magnesium sulfate, filtered, and
concentrated. The resulting residue is purified on silica gel (25-75% EtOAc/hexanes) to give
the racemic title compound as a pale yellow solid (3.27 g, 58%>). NMR analysis indicates the
relative stereochemistry shown. 1H-NMR (400 MHz, DMSO-d ) d 7.48 (d, J= 8.8 Hz, 1H),
6.89 (d, J= 8.8 Hz, 1H), 5.60-5.58 (m, 1H), 4.74 (d, J= 5.4 Hz, 1H), 4.27 (s, 1H), 3.82-3.80
(m, 1H), 3.55-3.53 (m, 1H), 3.29 (s, 1H), 3.15 (d, J= 5.2 Hz, 1H), 2.20 (s, 3H), 2.04-2.01 (m,
1H), 1.86-1.84 (m, 1H), 1.64-1.61 (m, 2H), 0.95 (s, 3H). LC-ES/MS m/z 281 (M+l).
The compound is dissolved in isopropanol and chloroform (2:1). The enantiomers
are separated in 150 mg injections by supercritical fluid chromatography on a
CHIRALPAK® AD-H column (0.5 1.5 cm). Mobile phase: 30%> isopropanol/carbon
dioxide. Flow rate: 300 mL/min. Detection: 290 nm. The first eluting peak is obtained as
Isomer 1 and the second eluting peak is obtained as Isomer 2. The enantiomeric excess is
determined by SFC on a CHIRALPAK® AD-H (4.6 100 mm) column using 20%
isopropanol/carbon dioxide. Detection: 215 nm.
Example 20, (Isomer 1 - 1S,2R,3S): Isolated as a white solid (1.5 g, 27%>). TR = 1.80 min,
>99% ee. LC-ES/MS m/z 281 (M+l).
Example 21, (Isomer 2 - 1R,2S,3R): Isolated as a white solid (1.4 g, 25%). TR = 2.75 min,
>99% ee. LC-ES/MS m/z 281 (M+1). The absolute stereochemistry (1R,2S,3R) of Isomer 2
is determined by X-ray of AR co-crystal as depicted above for the drawing of Example 2 1.
Example 22
re/-2-Chloro-4-[[(lR,2S,3S)-2,3-dihydroxy-2-methyl-cyclopentyl]amino]-3-methylbenzonitrile
The title compound is prepared by essentially following the procedure described in
Example 1, using re/-(lS,2R,5S)-2-amino-5 -(t rt-butyl(diphenyl)silyl)oxy-l-methylcyclopentanol
(409 mg, 1.1 mmol, Preparation 43) and 2-chloro-4-fluoro-3-methylbenzonitrile
(142 mg, 0.84 mmol). A 0.2 M solution of the crude product in THF is treated
with tetrabutylammonium fluoride ( 1.3 mL, 1.3 mmol, 1.0 M in THF) and stirred at room
temperature for 16 h. The mixture is treated with water, concentrated in vacuo and extracted
with EtOAc. The organic extracts are dried over magnesium sulfate, filtered, and
concentrated. The resulting material is purified on silica gel (25-100% EtOAc/hexanes) to
give the title compound as a pale yellow oil (15 mg, 6%>). The relative stereochemistry is
determined by NMR studies. 1H-NMR (400 MHz, DMSO-d ) d 7.47 (d, J= 8.8 Hz, 1H), 6.78
(d, J= 8.8 Hz, 1H), 5.60-5.57 (m, 1H), 4.98 (d, J= 4.2 Hz, 1H), 4.68 (s, 1H), 3.73-3.70 (m,
2H), 2.12 (s, 3H), 2.09-2.09 (m, 2H), 1.69-1.67 (m, 1H), 1.52-1.49 (m, 1H), 1.07 (s, 3H).
LC-ES/MS m/z 281 (M+1).
Example 23
rel -2-Chloro-4-[[(lR,2S,3R)-2,3-dihydroxy-2-methyl-cyclopentyl]amino]-3-ethylbenzonitrile
tive
The title compound is prepared by essentially following the procedure described in
Example 20, using re/-(lS,2R,5R)-2-amino-5 -(t r t-butyl(diphenyl)silyl)oxy-l-methylcyclopentanol
and 2-chloro-3-ethyl-4-fluoro-benzonitrile for the substitution reaction
followed by TBDPS removal with TBAF. 1H-NMR (400 MHz, DMSO-d ) d 7.44 (d, J= 8.7
Hz, 1H), 6.87 (d, J= 9.0 Hz, 1H), 5.74-5.70 (m, 1H), 4.74 (d, J= 5.4 Hz, 1H), 4.27 (s, 1H),
3.82-3.79 (m, 1H), 3.58-3.51 (m, 1H), 2.80-2.78 (m, 2H), 2.03-2.02 (m, 1H), 1.88-1.86 (m,
1H), 1.69-1.68 (m, 1H), 1.52-1.51 (m, 1H), 1.01-0.97 (m, 3H), 0.93 (s, 3H). LC-ES/MS m/z
295 (M+l).
Example 24
2-Chloro-4-[[(lR,2S)-2-hydroxycyclohexyl]amino]-3-methyl-benzonitrile
A mixture of 2-chloro-4-fluoro-3-methyl-benzonitrile (500 mg, 2.95 mmol),
diisopropylethylamine (1.29 mL, 7.37 mmol), and (lS,2R)-2-aminocyclohexanol
hydrochloride (670 mg, 4.42 mmol, Acros®) is microwaved using a CEM® microwave at
190 °C for 2 h and 180 °C for 4 h. The mixture is diluted with dichloromethane and washed
with 1N HCl. The aqueous layer is extracted again with dichloromethane. The combined
organic phases are dried over sodium sulfate, filtered, and concentrated in vacuo. The
resulting residue is purified using radial chromatography, eluting with 2%
methanol/dichloromethane. The isolated product is recrystallized with ether and hexane to
yield the title compound as a white solid (231 mg, 29%). LC-ES/MS m/z 265.0 (M+1).
The compounds in Table 8 below are prepared by essentially following the procedure
described in Example 24, using the appropriate chiral amino-alcohol (commercially
available) and 2-chloro-4-fluoro-3-methyl-benzonitrile.
Table 8
Example 28
2-Chloro-4-[[(lS,2R)-2-hydroxycyclohexyl] amino]-3-methyl-benzonitrile
A solution of 2-chloro-4-fluoro-3 -methyl-benzonitrile (500 mg, 2.95 mmol), (1R,2S)-
2-aminocyclohexanol hydrochloride (671 mg, 4.42 mmol, Small Molecules, Inc.) and sodium
bicarbonate (991 mg, 11.8 mmol) in DMSO (14.7 mL), and water (2.1 mL) is heated at
130 °C for 48 h. After cooling to room temperature, the mixture is diluted with 1N HCl and
extracted twice with EtOAc. The organic layers are combined, dried over sodium sulfate,
filtered, and concentrated in vacuo. The resulting residue is purified using radial
chromatography, eluting with 2% methanol/dichloromethane to furnish the title compound as
an off-white solid (527 mg, 68%). LC-ES/MS m/z 265.2 (M+l).
Example 29 and 30
2-Chloro-4-[ [3-hydroxy-3 -methyl-tetrahydropyran-4-yl] amino]-3-methyl-benzonitrile,
Diastereomer 1 and 2-Chloro-4-[[3-hydroxy-3-methyl-tetrahydropyran-4-yl]amino]-3-
methyl-benzonitrile, Diastereomer 2
Diastereomer 1 Diastereomer 2
To a solution 2-chloro-3-methyl-4-[(3-oxotetrahydropyran-4-yl)amino]benzonitrile
(2.53 g, 9.56 mmol, Preparation 46) in THF (38 mL) at 0 °C is added methylmagnesium
bromide (9.56 mL, 28.7 mmol, 3 M in diethyl ether) and the reaction is allowed to warm to
room temperature. After 1 h, the reaction is quenched with saturated aqueous ammonium
chloride. EtOAc is added and the mixture is washed with water. The organic portion is dried
with sodium sulfate, filtered, and concentrated in vacuo. The resulting residue is purified
using silica gel chromatography eluting with 5% MeOH/dichloromethane. The resulting
material is repurified with 2% MeOH/dichloromethane, then again with 1.5%
MeOH/dichloromethane to separate the diastereomers. Each product is recrystallized using
dichloromethane and ether to yield the title products.
Example 29, Diastereomer 1: Isolated as an off-white solid (549 mg, 21%). The relative
stereochemistry is unknown. 1H-NMR (400 MHz, DMSO-d ) d 7.47 (d, J= 8.7 Hz, 1H),
6.74-6.72 (m, 1H), 5.04-5.00 (m, 1H), 4.95 (s, 1H), 3.80-3.75 (m, 1H), 3.58-3.54 (m, 2H),
3.42-3.38 (m, 1H), 3.26 (d, J= 7.6 Hz, 1H), 2.15 (s, 3H), 1.72-1.69 (m, 2H), 0.94 (s, 3H).
LC-ES/MS m/z 281.2 (M+l).
Example 30, Diastereomer 2 : Isolated as an off-white solid (300 mg, 11%). The relative
stereochemistry is unknown. 1H-NMR (400 MHz, DMSO-d ) d 7.42 (d, J= 8.7 Hz, 1H), 6.94
(d, J= 9.0 Hz, 1H), 5.28-5.24 (m, 1H), 4.68 (s, 1H), 3.82-3.78 (m, 1H), 3.61-3.60 (m, 1H),
3.40 (d, J= 10.9 Hz, 1H), 3.35-3.31 (m, 1H), 3.09 (d, J= 11.0 Hz, 1H), 2.19 (s, 3H), 1.77-1.75
(m, 2H), 1.1 1 (s, 3H). LC-ES/MS m/z 281.2 (M+l).
Example 31 and 32
2-Chloro-3 -ethyl-4- [[3-hydroxy-3 -methyl-tetrahydropyran-4-yl] amino]benzonitrile,
Diastereomer 1 and 2-Chloro-3-ethyl-4-[[3-hydroxy-3-methyl-tetrahydropyran-4-
yl]amino]benzonitrile, Diastereomer 2
Diastereomer 1 Diastereomer 2
The title compounds are prepared as racemic diastereomers in a manner analogous to
the preparation found in Examples 29 and 30. The diastereomers are separated using silica
gel chromatography eluting with 1.5% MeOH/dichloromethane. The diastereomers are
further purified and separated using silica gel chromatography eluting with 10%
acetone/ dichloromethane .
Example 31, Diastereomer 1: Isolated as an off-white solid (551 mg, 19%). The relative
stereochemistry is unknown. 1H-NMR (400 MHz, DMSO-d ) d 7.47-7.45 (m, 1H), 6.76-6.73
(m, 1H), 5.16-5.14 (m, 1H), 5.04-4.99 (m, 1H), 3.84-3.81 (m, 1H), 3.60-3.58 (m, 2H), 3.43-
3.42 (m, 1H), 3.26-3.23 (m, 1H), 2.71-2.70 (m, 2H), 1.72-1.70 (m, 2H), 1.12-1.02 (m, 3H),
0.95 (s, 3H). LC-ES/MS m/z 295.0 (M+l).
Example 32, Diastereomer 2: Isolated as an off-white solid (392 mg, 13%). The relative
stereochemistry is unknown. 1H-NMR (400 MHz, DMSO-d ) d 7.40 (d, J= 8.9 Hz, 1H), 6.96
(d, J= 9.1 Hz, 1H), 5.41-5.38 (m, 1H), 4.69 (s, 1H), 3.86-3.81 (m, 1H), 3.59-3.58 (m, 1H),
3.42-3.38 (m, 1H), 3.34-3.28 (m, 1H), 3.1 1-3.07 (m, 1H), 2.78-2.75 (m, 2H), 1.81-1.80 (m,
1H), 1.67-1.63 (m, 1H), 1.10 (s, 3H), 1.01 (t, J= 7.4 Hz, 3H). LC-ES/MS m/z 295.0 (M+l).
Example 33 and 34
2-Chloro-3 -ethyl-4- [[3-hydroxy-3 -methyl-tetrahydropyran-4-yl] amino]benzonitrile, Isomer 1
and 2-Chloro-3-ethyl-4-[[3-hydroxy-3-methyl-tetrahydropyran-4-yl]amino]benzonitrile,
Isomer 2
Example 32 (Diastereomer 2) is dissolved in 2:1 methanol/dichloromethane (9 mL)
and separated in 1000 injections by supercritical fluid chromatography on a
CHIRALPAK® AD-H column (2.1 x 15 cm, 5 mpi) . Mobile phase: 25% ethanol/carbon
dioxide. Flow rate: 70 mL/min. Detection: 225 nm. Each run is 3.5 min. The first eluting
peak is obtained as Isomer 1 and the second eluting peak is obtained as Isomer 2. The
enantiomeric excess is determined by SFC on a CHIRALPAK® AD-H (2.1 x 15 cm, 5 mih)
column using 25% ethanol/carbon dioxide. Flow rate: 5 mL/min. Detection: 225 nm.
Example 33, Isomer 1: Isolated as an off-white foam (256 mg, 49%). TR = 1.14 min, 99%
ee.
Example 34, Isomer 2: Isolated as an off-white foam (221 mg, 42%) TR = 1.86 min, 99% ee.
1H-NMR (400 MHz, DMSO-d ) d 7.47-7.45 (m, 1H), 6.76-6.73 (m, 1H), 5.16-5.14 (m, 1H),
5.04-4.99 (m, 1H), 3.84-3.81 (m, 1H), 3.60-3.58 (m, 2H), 3.43-3.42 (m, 1H), 3.26-3.23 (m,
1H), 2.71-2.70 (m, 2H), 1.72-1.70 (m, 2H), 1.12-1.02 (m, 3H), 0.95 (s, 3H). LC-ES/MS m/z
295.0 (M+l).
Steroid hormone nuclear receptor binding assay
Cell lysates from human embryonic kidney HEK293 cells overexpressing human MR
(mineralocorticoid receptor), GR (glucocorticoid receptor), AR (androgen receptor), or PR
(progesterone receptor) are used for receptor-ligand competition binding assays to determine
Ki values. Typical procedures are provided below.
Briefly, steroid receptor competition binding assays are run in a buffer containing 20
mM HEPES buffer (pH = 7.6), 0.2 mM EDTA, 75 mM NaCl, 1.5 mM MgCi2, 20% glycerol,
20 mM sodium molybdate, 0.2 mM DTT, 20 mg/mL aprotinin and 20 mg/mL leupeptin (assay
buffer). Typically, steroid receptor binding assays include radio-labeled ligands, such as 0.25
nM [ H]-aldosterone for MR binding, 0.3 nM [ H]-dexamethasone for GR binding, 0.36 nM
[^HJ-methyltrienolone for AR binding, and 0.29 nM [^HJ-methyltrienolone for PR binding,
and either 20 mg 293-MR lysate, 20 mg 293-GR lysate, 22 mg 293-AR lysate, or 40 mg 293-
PR lysate per well. Assays are typically run in 96-well format. Competing test compounds
are added at various concentrations ranging from about 0.01 nM to 10 mM. Non-specific
binding is determined in the presence of 500 nM aldosterone for MR binding, 500 nM
dexamethasone for GR binding, or 500 nM methyltrienolone for AR and PR binding. The
binding reactions (140 m ) are incubated overnight at 4 °C, then 70 m of cold charcoaldextran
buffer (containing per 50 mL of assay buffer, 0.75 g of charcoal and 0.25 g of
dextran) is added to each reaction. Plates are mixed for 8 min on an orbital shaker at 4 °C.
The plates are then centrifuged at 3,000 rpm at 4 °C for 10 min. An aliquot of 120 m of the
binding reaction mixture is then transferred to another 96-well plate and 175 m of Wallac
Optiphase Hisafe 3™ scintillation fluid is added to each well. Plates are sealed and shaken
vigorously on an orbital shaker. After an incubation of 2 h, plates are read in a Wallac
MICROBETA® counter.
The data are used to calculate an estimated IC50 and percentage inhibition at 10 mM.
The Kd for [^HJ-aldosterone for MR binding, [^HJ-dexamethasone for GR binding, [¾]-
methyltrienolone for AR binding, or [^HJ-methyltrienolone for PR binding, is determined by
saturation binding. The IC 0 values for compounds are converted to Ki using the Cheng-
Prushoff equation.
The compounds of the Examples herein were tested essentially as described above
and exhibited a Ki value for AR of lower than 1 mM. The following exemplified compounds
of the invention were tested essentially as described above and exhibited the following
affinity for AR as illustrated in Table 9 below.
Table 9
Ex AR (Ki nM) GR (Ki nM) MR (Ki nM) PR (Ki nM)
1 2.03 >6020 1450 872
2 0.684 462 1840 448
5 16.9 >3120 415 520
16 5.21 2390 >7010 1220
20 38.1 >5730 >7150 >7960
32 162 >5820 3960 4290
The data in Table 9 show that the compounds of Table 9 are potent and selective
ligands for the AR.
C2C12 AR/ARE reporter assay
As an indicator of agonist activity in muscle tissue, the C2C12 AR/ARE reporter
assay is performed. Briefly, mouse myoblast C2C12 cells are co-transfected using Fugene™
reagent. A reporter plasmid containing a GRE/ARE (glucocorticoid response
element/androgen response element) and TK promoter upstream of the luciferase reporter
cDNA, is transfected with a plasmid constitutively expressing human androgen receptor
(AR) using viral CMV promoter. Cells are transfected in T150 cm2 flasks in DMEM media
with 4% CS-FBS. After a 5 h incubation, transfected cells are trypsinized, plated in 96 well
dishes in DMEM media containing 4% CS-FBS, incubated for 2 h and then exposed to
various concentrations of test compounds ranging from about 0.01 nM to 10 mM . After 24 h
of incubations with compounds, cells are lysed and luciferase activity is determined by
standard techniques. Data is fit to a 4 parameter-fit logistics to determine EC50 values. The
% efficacy is determined versus maximum stimulation obtained with 10 nM
methyltrienolone .
Functional assays of steroid hormone nuclear hormone receptor modulation similar to
those described above can be readily designed by the ordinarily skilled artisan. The
compounds of the Examples herein were tested essentially as described above as illustrated
in Table 10 below.
Table 10
The data in Table 10 demonstrate that the compounds of Table 10 are an agonist of human
AR.
In vivo model of efficacy and selectivity
Hypogonadism induced sarcopenia muscle atrophy can occur as a result of various
disease conditions including aging, cancer cachexia, sepsis, denervation, disuse, inactivity,
burns, HIV-acquired immunodeficiency syndrome (AIDS), chronic kidney or heart failure,
unloading/microgravity, and muscular dystrophies etc. The sequence of events that leads to
muscle loss under these various conditions is different, but collectively leads to an imbalance
in muscle anabolic and muscle catabolic pathways, such that there is a net loss in muscle
mass and function that can be measured in a delayed rat gonadectomy model via changes in
Levator Ani (LA) muscle and Bulbo Cavernosus (BC) perineal muscle wet weights.
Male Sprague Dawley rats (8 weeks old) are castrated (gonadectomized or "GDX")
according to approved procedures (Charles River Labs) and allowed to waste for six weeks.
Age-matched sham-operated rats are also prepared. (Sham-operated rats are animals that
have been exposed to the same surgical procedures as castrated animals except their testes
are not removed.) Animals are housed in a temperature-controlled room (24 °C) with a
reversed 12 hour light/dark cycle (dark 10:00/22:00) and water and food are available ad
libitum.
In order to demonstrate in vivo efficacy, compounds of the present invention are
administered daily by transdermal application to the castrated 14 week old rats (body weight
about 400-450 g). Animals are randomized based on body weight prior to ascribing a test
slot, such that the starting body weights of all treatment groups are within 5% of each other.
Test compounds are administered to the animals using conventional vehicles. For example,
for transdermal formulation, 81.6% ethanol, 7.6% isopropyl myristate, 9.6% water, 0.4%
Carbopol®, 0.826% edetol (ethylenediamine-N,N,N',N'-tetra-2-propanol) is used. Sham
operated rats receiving no treatment are used as treatment positive controls whereas castrated
rats treated only with vehicle are used as treatment negative controls.
Test animals are dosed transdermally over a two week timeframe with, for example,
0.3, 1, or 5 mg/kg/day of a compound of the present invention. After the two-week
treatment, as an indicator of activity, the wet weight of the LA muscle and the BC muscle in
the test group is determined and compared to the wet weight of the LA and the BC from the
castrated, vehicle-only control group. The wet weights of the muscle obtained in both the
test group and the vehicle-only group are normalized relative to total body weight. As an
indicator of tissue selective activity, the wet weight of the prostate (P) from test animals is
similarly compared to the wet weight of the prostates from the sham control group. Again,
the wet weights of the prostates obtained from both the test group and the sham control group
are normalized relative to total body weight.
Percent Efficacy (% Eff) values may be determined as follows: % Eff = ((Wet
weight of LA or BC or P in test animal / test animal total body weight) / (Wet weight of LA
or BC or P in control animal / control animal total body weight)) x 100.
Following procedures essentially as described above, the compound of Example 1
displays the following activity in the afore-mentioned rat in vivo model of efficacy and
selectivity as shown in Table 11 below:
Table 11
TD = transdermal route of administration; LA e; BC = bulbo cavernosus
muscle; P = prostate; GDX = gonadectomized
Similarly, the compound of Example 2 displays the following activity in the afore
mentioned rat in vivo model of efficacy and selectivity as shown in Table 12 below:
Table 12
TD = transdermal route of administration; LA = levator ani muscle; BC = bulbo cavernosus
muscle; P = prostate; GDX = gonadectomized
Collectively, these results demonstrate that Example 1 and Example 2 are Selective
Androgen Receptor Modulators (SARMs) that show a dose-dependent increase in the highly
responsive striated muscles LA and BC after 2 weeks of treatment, with minimal accrual of
androgenic risk (increase in prostate wet weights) in the same animals using a delayed rat
gonadectomy model.
In vivo model of HDL cholesterol lowering induced by AR modulators
Cynomolgus monkeys are used for this study, which is conducted to evaluate the
effects of androgen receptor modulators on HDL (high-density lipoprotein) cholesterol. This
animal model has been shown to respond to androgens by lowering of HDL cholesterol, and
is considered predictive of the same response in humans (Nantermet P., et al, Endocrinol
149(4):1551-1561).
Young adult female monkeys, approximately 5-8 kg in weight, are individually
housed in a climate-controlled room (temperature 72 ± 8 °F and relative humidity 30%-70%)
with a 12 hour light/dark cycle and water and food available ad libitum. Compounds of the
present invention are administered daily by topical application to 6 monkeys/compound for 2
weeks. If more than one compound is tested in a given study, monkeys are assigned to
groups such that each group has similar body weights. Two application sites on the back of
the neck are shaved, and compound is applied by spreading over a shaved area using a 1mL
syringe with a 16-gauge needle. Daily application is alternated between the two sites to
minimize the potential for skin irritation. Test compounds are administered to the animals
using vehicles appropriate for topical application such as a combination of 81.6% ethanol,
7.6% IPM, 9.6% water, 0.4% Carbopol®, and 0.826% edetol (ethylenediamine-N,N,N ,N -
tetra-2-propanol). The standard dose volume is 0.15 mL/kg.
Prior to initiation of dosing, blood is drawn from the monkeys on at least 2 days,
following an overnight fast, for the purpose of establishing a baseline for clinical pathology
parameters (defined as a Cheml8 + HDL panel, which includes hematology and serum
clinical chemistry parameters). The first day of dosing is defined as Day 1. Blood is also
drawn three times during the course of the 14-day study (for example, on Days 3, 7 and 13)
for evaluation of the Cheml8 + HDL panel using the Roche Systems Analyzer. Animals are
fasted overnight prior to this procedure. Monkeys are observed daily for abnormalities
(including skin irritation) and signs of pain or distress. Body weights are collected prior to
dosing and near study termination. Blood is also collected for evaluation of pharmacokinetic
endpoints, to confirm exposure on Days 1 and 14. Additional parameters are assessed to
evaluate the health of the animals.
Following procedures essentially as described above, the compound of Example 1
displays the following activity in the afore-mentioned monkey in vivo model of HDL
lowering after 3, 7, and 14 doses as shown in Table 13 below. HDL cholesterol data are
expressed as percent decrease relative to the arithmetic mean of two baseline determinations
prior to dosing.
Table 13
These data demonstrate that transdermal delivery of the compound of Example 1 has a
minimal effect on HDL in monkeys.
We claim:
1. A compound of formula:
wherein
n is 1 or 2;
X is -CH 2- or -0-;
R1 is -CH 3 or -CH 2CH3;
R2 is - H or -CH 3;
R3 is - H or -OH;
wherein R is - H when X is -0-;
or a pharmaceutically acceptable salt thereof.
A compound of Claim 1 of the formula
wherein
n is 1 or 2;
R is -CH 3 or -CH 2CH3;
R2 is - H or -CH 3;
R3 is - H or -OH;
or a pharmaceutically acceptable salt thereof.
3. A compound of Claim 1 or 2 of the formula:
wherein
R1 is -CH 3 or -CH 2CH3;
R2 is - H or -CH 3;
R3 is - H or -OH;
or a pharmaceutically acceptable salt thereof.
4. A compound of any of Claims 1 to 4 of the formula:
or a pharmaceutically acceptable salt thereof.
5. A compound of any of Claims 1 to 4 having the formula
or a pharmaceutically acceptable salt thereof.
A compound of Claim 5 that is 2-chloro-4-[[(lR,2R)-2-hydroxy-2-methylcyclopentyl]
amino]-3-methyl-benzonitrile.
7. A compound of any of Claims 1 to 4 having the formula
or a pharmaceutically acceptable salt thereof.
8. A compound of Claim 7 that is 2-Chloro-4-[[(lS,2R)-2-hydroxy-2-methylcyclopentyl]
amino]-3-methyl-benzonitrile.
9. A pharmaceutical composition comprising a compound of any of Claims 1 to 8, or a
pharmaceutically acceptable salt thereof, and one or more pharmaceutically
acceptable carriers, diluents, or excipients.
10. A pharmaceutical composition according to Claim 9 which is formulated as a patch.
11. A pharmaceutical composition according to Claim 9 which is formulated as a topical
gel.
12. A pharmaceutical composition according to Claim 9 which is formulated as a topical
cream.
13. A pharmaceutical composition according to Claim 9 which is formulated as a topical
spray.
14. A pharmaceutical composition according to Claim 9 comprising a solvate.
15. A pharmaceutical composition according to Claim 14 which is 2-chloro-4-[[(lR,2R)-
2-hydroxy-2-methyl-cyclopentyl]amino]-3-methyl-benzonitrile • ethanol solvate in
crystalline form characterized by an X-ray powder diffraction pattern obtained from a
CuKa source (l = X A) which comprises peaks at:
a) 7.00, 17.26, 12.30, and 23.34 +/- -0.2 in 2Q; or
b) 7.00, 8.59, 12.30, 16.76, 17.26, and 23.34 +/- -0.2 in 2Q; or
c) 7.00, 8.59, 10.13, 11.89, 12.30, 12.91, 13.95, 16.76, 17.26, 23.34 +/- -0.2 in
2Q.
16. A method for the treatment of muscle atrophy in a patient comprising administering
to a patient in need of such treatment an effective amount of a compound of any of
Claims 1 to 8, or a pharmaceutically acceptable salt thereof.
17. A method according to Claim 16 for the treatment of muscle atrophy associated with
hip or knee replacement or hip fracture.
18. A compound of any of Claims 1 to 8, or a pharmaceutically acceptable salt thereof,
for use in therapy.
19. A compound of any of Claims 1 to 8, or a pharmaceutically acceptable salt thereof,
for use in treating muscle atrophy.
20. The use of a compound of any of Claims 1to 8, or a pharmaceutically acceptable salt
thereof, for the manufacture of a medicament for the treatment of muscle atrophy.