HELD OF THE INVENTION
The present invention related to purine derivatives of formula (T) as kinase inhibitors.
BACKGROUND OF THE INVENTION
Glycogen synthase kinase-3 (GSK-3) is a serine'threonine protein kinase first discovered as one of a
number of kinases capable of phosphorylating and inactivating glycogen synthase, the regulatory
enzyme of glycogen synthesis in mammals (Embi. et al.. Eur. .1. Biochem.. 107.519-527 (1980)).
Existing in two isoforms. GSK-3a and GSK-3B. GSK-3 phosphorylates a wide variety of proteins in
vitro. The diversity of these proteins suggests a role for GSK-3 in the control of cellular metabolism,
growth, and development.
Type I diabetes is characterized by a lack of insulin resulting from the destruction ol" insulin
producing cells in the pancreas. Type II diabetes is characterized by defective insulin secretion and
action. The binding of insulin to its receptor initiates a cascade of events resulting in the
phosphorylation and inhibition of GSK-3. contributing to the insulin-induced stimulation of glycogen
and protein synthesis. Inhibitors of GSK-3 have been shown to mimic the actions of insulin (Coghlan.
et al.. Chem. Biol.. 7.793-803 (2000)). including the ability to lower b100d glucose levels in \ivo
(Norman, Drug News Perspect, 14.242-247 (2001)). These recent discoveries suggest that inhibitors
of GSK-3 have a potential role in the treatment of diabetes.
Alzheimer's disease is characterized by the micro-lubule-associated protein Tan existing in an
abnormally hyperphosphorylated state (Cohen and Frame. Nature Reviews: Molecular Cell Biology.
2,769-776 (October 2001) 1000 ng*hr/rnL. Additionally, those GSK-3 inhibitors exhibiting
a low IC50 value, such as below 10 nm, and plasma exposures <1000 ng*hr/mL
represent a further preferred embodiment of the present invention.
Glycogen Synthesis Assay
The glycogen synthesis assay measures the increase in the production of glycogen
both in the absence and in the presence of insulin in the cells. This test is done according
to standard protocols. (Berger, J. and Hayes, N.S., Anal. Biochem., 261,159-163 (1998)).
Briefly, 3T3-L1 adipocytes are plated and differentiated in a 96-well plate at 25,000
cells/well. The plate is serum-starved overnight. The serum-starvation media is removed
just prior to assay, and the plate is washed with 100 µl/well Krebs-Ringer-Hepes buffer
(KRBH). The KRBH is removed and 50 u.1 of compound (twice the amount of the final
concentration) is added to the assay plate. Next, 50 µl of 14C-labeled glucose is added to
the assay plate at 0.1 µCi/well. The plate is then incubated at 37°C for 2 hours.
The plate is washed with 100 µL/well of PBS, and the cells are lysed with 75
µl/well of 1N NaOH. The plate is heated at 70°C for 20 minutes. An aliquot (50 µl)
of the supernatant is transferred from the assay plate to a Millipore FC filter plate
containing 120 µl/well of ice-cold ethanol. The plate is allowed to stand for 2 hours at
4°C to facilitate precipitation. The ethanol is removed from the filter plate via a
vacuum manifold, and the plate is washed with 100 µL/well of ice-cold 70% ethanol.
The plate was allowed to dry overnight, and 75 µl/well of Microscint-20 was added to
the filter plate. The plate was then counted on a Packard Topcount. The compound of
Example 121 was tested in this assay and increased glycogen synthesis by 3.7-fold at
0.1µM in the absence of insulin, and increased glycogen synthesis by 6.4-fold at
0.lµM in the presence of insulin.
Glucose Lowering Assay
The glucose lowering assay is an in vivo test that measures the effect of the
test compound on b100d glucose and triglycerides relative to insulin. (ELDAR-
FINKLEMAN, H., et ah, Expression and Characterization of Glycogen Synthase
Kinase-3 Mutants and Their Effect on Glycogen Synthase Activity in Intact Cells,
Proc. Nat. Acad. Sci, 93, 10228-10233 (1996)). Briefly, ZDF rats (Charles River,
Inc.) at six weeks of age are housed individually with free access to food and water.
Rats are dosed with drug once daily by oral gavage, with the compound prepared as a
suspension in 1% caboxymethylcellusolve/0.25% Tween 80 (CMC-Tween). Vehicle
controls' are dosed with CMC-Tween only. The duration of study varied according to
the protocol used, with acute dosing studies lasting one day and dose escalation
studies lasting seven days. Body weights and food consumption measurements are
also performed once a week for seven-day studies. For measurement of b100d glucose
and triglycerides, b100d samples of 600 µl are collected by the tail snip method. (The
tail snip for b100d sampling is as follows: 1-2 mm of the tail is snipped with a sharp
blade. After collection of b100d, a scab.forms at the site of wound. This scab is
removed and the tail is gently massaged for other subsequent bleedings.) Glucose and
triglyceride determinations are performed on a Hitachi 912 metabolic analyzer, with a
kit utilizing the Trinder method. On termination of study, specific tissues (e.g., heart,
pancreas, adipose tissues, and liver) are excised to evaluate the effect of these drugs
on their metabolic functions. The compound of Example 121 was tested in this assay
and lowered glucose by 56% at a dose of 10 mg/kg.
Ex Vivo Brain Assay
The ex vivo brain assay assesses the GSK-3P kinase activity of the test compound
in brain cortex tissue according to standard protocols (Wang, et al., Anal. Biochem., 220,
397-402 (1994)).
The ex vivo GSK-3ß kinase activity of a compound is assayed following oral
dosing of 2 to 3 month old PDAPP or CD-I mice. After a 20 mg/kg, 24-hour dose,
followed by an additional three-hour dose, brain cortex tissue is dissected and
homogenized in freshly prepared lysis buffer (10 mM K2HPO4 pH 7.2,1 mM EDTA, 5
mM EGTA, 10 mM MgCl2, 50 mM ß-Glycerophosphate, 1 mM Na3VO4, 2 mM DTT, 1
uM Microcystis COMPLETE protease inhibitor tablet, no detergent). Following a thirty-
minute incubation on ice, cortex homogenate samples are centrifuged (100,000 G) for 30
minutes at 4°C (Ahmed, N.N., et al., Oncogene, 8,1957 (1983)). The total protein
concentration of homogenate is determined using the BCA method (Pierce). GSK-3ß
activity in cytosolic homogenate from vehicle- and compound-treated mice is then
assayed. The kinase reaction occurs in a 50 µ1 total volume containing 20 mM MOPS pH
7.4, 25 mM ß-glycerol phosphate, 5 mM EGTA, 1 mM NA3VO4, 1 mM DTT, 15 mM
MgCl2, 100 µM cold ATP, 200 µM CREB peptide, 10 µL cytosolic cortex brain
homogenate, and 5 µCi ?-33P-ATP. The reactions are incubated for thirty minutes at 30°C
using a Costar round-96 polypropylene plate. Reactions are then stopped with the
addition of 10% H3PO4 and transferred to a Millipore MAPH-NOB 96-well
phosphocellulose plate. Next, the reaction is incubated at room temperature for 1.5 hours,
filtered and washed with 320 µl 0.75% H3PO4, and filtered and washed with 160 µl
H3PO4 at the same concentration using a vacuum manifold. The filter plate is then placed
in a carrier plate, and 100µl of Microscint 20 is added to each well. The plate is sealed
with sealing tape and incubated overnight at room temperature. The following day, the
filter plate is read for 33P on Top Count (Packard). Finally, CPM is normalized to CPM
per µg of total protein. The compound of Example 121 was tested in this assay and
inhibited kinase activity by 30% at a dose of 20 mg/kg.
Beta-Catenin Protection Assay
The beta-catenin assay is the fold induction over basal beta-catenin and is
performed according to standard protocols (Hedgepeth, CM., Dev. Biol., 185, 82-91
(1997); Chen, G., et al., J. Neurochem., 72,1327-1330 (1999); Hong, M., et al., J.
Biol. Chem.. 272, 25326-25332 (1997)).
The human familial Alzheimer's disease (FAD) presenilin-1 AG04160C
lymphoblast cell line (Coriell Cell Repository, Camden, NJ) is maintained as a suspension
culture in RPMI1640 (with L-Glutamine) supplemented with 10% fetal bovine serum and
1% penicillin-streptomycin in an atmosphere of 37°C and 5% CO2. The AG04160C FAD
lymphoblast cells are seeded in T-25 cm2 flasks at 2.5 to 5.0 X105 cells/ml in a total
volume of 10 ml. Following 16-18 hours of growth, cells are treated with compound at
concentrations of 0.1 µM, 1.0 µM, and 10 µM, and are incubated for an additional 24
hours. At the completion of the 24-hour incubation, cells are harvested, washed with PBS,
and lysed in freshly prepared lysis buffer (10 mM K2HPO4 pH 7.2, 1 mM EDTA, 5 mM
EGTA, 10 mM MgCl2, 50 mM ß-Glycerophosphate, 1 mM Na3VO4, 2 mM DTT, 1 µM
Microcystin, 1 mM PMSF, 10 µg/ml leupeptin, 1 µg/ml pepstatin, 1 µg/ml aprotinin, 1%
Triton X-100). After a thirty-minute incubation on ice, cells are centrifuged (14,000 rpm)
for 30 minutes at 4°C, and resulting supematants are used as whole cell lysates. The total
protein concentration in whole cell lysate samples is determined using the BCA method
(Pierce). Next, 15 µg of sample is loaded on a 10% Bis-Tris NuPage gel and transferred
to a pure nitrocellulose membrane followed by P-catenin immunoblot analysis using a ß-
catenin specific antibody (Transduction Labs). The P-catenin accumulation/stability is
then quantified following densitometry analysis of protein bands (Kodak Digital Science).
Final results are reported as fold induction over basal p-catenin. The compound of
Example 121 was tested in this assay and induced a 9.8-fold induction of ß-catenin at 0.1
MM.
Bone Deposition
Vehicle or test compound in vehicle (1% Carboxymethylcellulose sodium, 0.25%
Polysorbate 80, and 0.05% Dow Corning Antifoam 1510-US in purified water) is
administered orally by gavage to female Fischer 344 rats daily for 4 days with three rats in
each dosage group. The rats are delivered for necropsy and sections of formalin-fixed,
paraffin-embedded bone are examined microscopically to evaluate osteoblast proliferation
and deposition of osteoid.
The compounds in the following tables were tested essentially as described above
and hypertrophy and proliferation of osteoblasts along surfaces of medullary trabecula and
the cortical periosteum accompanied by production of osteoid was observed.
"+" = hypertrophy and proliferation of osteoblasts with production of osteoid observed
"-" = hypertrophy and proliferation of osteoblasts with production of osteoid not observed
at this dose
"Not tested" = compound not tested at this dose
The compound of Example 365 was tested again essentially as described above at
0, 3,10, and 30 mg/kg with four rats at each dosage level for 21 days. The vertebra and
the femur were submitted for analysis of bone mineral density (BMD), bone mineral
content (BMC), and cross sectional area following 21 days of daily dosing with the
compound of Example 365. The results from this analysis indicate a significant increase
in BMD and BMC relative to control (p<0.05) without a significant change in cross
sectional area in both vertebra and femur. Osteoblast proliferation occurred early
followed by deposition of new bone by Day 21, but osteoblast proliferation and trabecular
hypertrophy were confined to rats given 30 mg/kg of the compound of Example 365 in
this study.
These data illustrate that short-term exposure to GSK-3 inhibitors stimulates
deposition of new and functional bone.
Ovariectomized Rat Assay
Six-month-old virgin Sprague-Dawley rats are maintained on a 12-hour light, 12-
hour dark cycle at 22°C with ad libitum access to food (TD89222 with 0.5% calcium and
0.4% phosphate, Teklad, Madison, WI) and water. Bilateral or sham ovariectomies are
performed on the rats and they are allowed to lose bone for 1 month. When the rats are 7
months old, sham and ovariectomized (Ovx) controls (7 animals per group) are orally
administered vehicle (1% carboxymethyl cellulose/0.25% Tween 80) and a second group
of 7 Ovx animals is orally administered the test compound in vehicle. Dosing is done
once a day for 2 months. At the end of 2 months, rats are euthanized using CO2
anesthesia and left femur and vertebra are removed, cleaned of soft tissue and stored in
50% ethanol/saline. Bones are analyzed by QCT as described previously (Sato M.,
Comparative x-ray densitometry of bones from ovariectomized rats. Bone 17:157S-162S
(1995); Sato M., Kim J,, Short L.L., Slemenda C.W, Bryant H.U., Longitudinal and cross-
sectional analysis of raloxifene effects on tibiae from ovariectomized aged rats. J
Pharmacol Exp Ther 272:1252-1259 (1995)).
Ovariectomy reduced vertebral bone mineral density (BMD) by 18 % and femoral
midshaft BMD by 5.1%. Oral administration of the compound of Example 252 at 3
mg/kg increased both vertebral BMD and femoral midshaft BMD back to sham control
levels (P<0.05 compared to Ovx control). Thus, the compound of Example 252 was
active in restoring lost bone both at trabecular and cortical bone sites.
Oral administration of the compounds of the present invention is preferred.
However, oral administration is not the only route or even the only preferred route. For
example, transdermal administration may be very desirable for patients who are forgetful
or petulant about taking oral medicine, and the intravenous route may be preferred as a
matter of convenience or to avoid potential complications related to oral administration.
Compounds of Formula I may also be administered by the percutaneous, intramuscular,
intranasal or intrarectal route in particular circumstances. The route of administration
may be varied in any way, limited by the physical properties of the drugs, the convenience
of the patient and the caregiver, and other relevant circumstances (Remington's
Pharmaceutical Sciences, 18th Edition, Mack Publishing Co. (1990)).
The pharmaceutical compositions are prepared in a manner well known in the
pharmaceutical art. The carrier or excipient may be a solid, semi-solid, or liquid material
that can serve as a vehicle or medium for the active ingredient. Suitable carriers or
excipients are well known in the art. The pharmaceutical composition may be adapted for
oral, inhalation, parenteral, or topical use and may be administered to the patient in the
form of tablets, capsules, aerosols, inhalants, suppositories, solutions, suspensions, or the
like.
The compounds of the present invention may be administered orally, for example,
with an inert diluent or capsules or compressed into tablets. For the purpose of oral
therapeutic administration, the compounds may be incorporated with excipients and used
in the form of tablets, troches, capsules, elixirs, suspensions, syrups, wafers, chewing
gums and the like. These preparations should contain at least 4% of the compound of the
present invention, the active ingredient, but may be varied depending upon the particular
form and may conveniently be between 4% to about 70% of the weight of the unit. The
amount of the compound present in compositions is such that a suitable dosage will be
obtained. Preferred compositions and preparations of the present invention may be
determined by methods well known to the skilled artisan.
The tablets, pills, capsules, troches, and the like may also contain one or more of
the following adjuvants: binders such as povidone, hydroxypropyl cellulose,
microcrystalline cellulose, or gelatin; excipients or diluents such as: starch, lactose,
microcrystalline cellulose or dicalcium phosphate, disintegrating agents such as:
croscarmellose, crospovidone, sodium starch glycolate, corn starch and the like; lubricants
such as: magnesium stearate, steric acid, talc or hydrogenated vegetable oil; glidants such
as colloidal silicon dioxide; wetting agents such as: sodium lauryl sulfate and polysorbate
SO; and sweetening agents such as: sucrose, aspartame or saccharin may be added or a
flavoring agent such as: peppermint, methyl salicylate or orange flavoring. When the
dosage unit form is a capsule, it may contain, in addition to materials of the above type, a
liquid carrier such as polyethylene glycol or a fatty oil. Other dosage unit forms may
contain other various materials that modify the physical form of the dosage unit, for
example, as coatings. Thus, tablets or pills may be coated with sugar, hydroxypropyl
methylcellulose, polymethacrylates, or other coating agents. Syrups may contain, in
addition to the present compounds, sucrose as a sweetening agent and certain
preservatives, dyes and colorings and flavors. Materials used in preparing these various
compositions should be pharmaceutically pure and non-toxic in the amounts used.
The compounds of Formula I are generally effective over a wide dosage range.
For example, dosages per day normally fall within the range of about 0.0001 to about
30 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 without causing any harmful side effect, 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 the compound actually administered will 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.
We Claim:
3-(9-Fluoro-6-((piperidin-l-yl)carbonyl)-6,7-dihydro-6H-[l,4]diazepino-[6,7,l-
hi]indol-l-yl)-4-(imidazo[l,2-a]pyridine-3-yl)-2,5-dioxopyrrole having structure:
or a pharmaceutically acceptable salt thereof.
2. 3-(9-Fluoro-6-((piperidin-l-yl)carbonyl)-6,7-dihydro-6H-[l ,4]dia/.epino-[6,7,l -
hi]indol-l-yl)-4-(imidazo[l,2-a]pyridine-3-yl)-2,5-dioxopyrrole hydrochloride
having structure:
3. A pharmaceutical composition comprising a compound of Claim 1 or 2 in
combination with a pharmaceutically acceptable carrier, diluent or excipient.

The present invention provides kinase inhibitors of Formula I.