SPECIFICATION
TITLE OF THE INVENTION
Selective process for producing an anomer of a 1-
phosphorylated saccharide derivative and process for
producing a nucleoside
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a process for producing a
1-phosphorylated saccharide derivative. 1-
phosphorylated saccharides are widely distributed in the
living world, are reaction substrates for a variety of
enzymes and are utilized starting materials for
preparing useful substances such as drugs and
nutritional foods. Synthetic 1-phosphorylated
saccharide derivatives have been expected to be used as
starting materials for preparing drugs such as antiviral
agents and enzyme inhibitors.
This invention also relates to a process for
producing a nucleoside compound used as a starting
material or drug substance for medical drugs such as
antiviral, anticancer and antlsense drugs.
2. Description of the Prior Art
There are known processes for producing a 1-
phosphorylated saccharide such as:
1) condensation of a 1-bromosaccharide with a
silver phosphate salt (J. Biol. Chem., Vol.121, p.465
(1937); J. Am. Chem. Soc. Vol.78, p.811 (1956); J. Am.
Chem. Soc, Vol.79, p.5057 (1957));
2) condensation of a 1-halogenated saccharide with
a triethylamine salt of dibenzylphosphoric acid (J. Am.
Chem. Soc, Vol.77, p.3423 (1955); J. Am. Chem. Soc,
Vol.80, p.1994 (1958); J. Am. Chem. Soc, Vol.106.
p.7851 (1984); J. Org. Chem., Vol.59, p.690 (1994));
3) thermal condensation of a 1-acetylated
saccharide with orthophosphoric acid (J. Org. Chem.,
Vol.27, p.1107 (1962); Carbohydrate Res.. Vol.3, p.117
(1966); Carbohydrate Res., Vol.3, p.463 (1967); Can. J.
Blochem., Vol.50, p.574 (1972));
4) condensation of dibenzylphoshoric acid with a
saccharide activated at 1-position by imidation
(Carbohydrate Res., Vol.61, p.181 (1978); Tetrahedron
Lett., Vol.23, p.405 (1982));
5) treatment of a saccharide activated at 1-
positlon by thallium or lithium alcolate with
dibenzylphosphoric chloride (Carbohydrate Res., Vol.94,
p.165 (1981); Chem. Lett., Vol.23, p.405 (1982));
6) phosphorolysis of a nucleoside utilizing action
of nucleoside phosphorylase to form a 1-phoshorylated
saccharide derivative (J. Biol. Chem., Vol.184, p.437
(1980) ) .
These processes have the following drawbacks.
A common problem in the chemical processes
described in the above 1) to 5) is that it is difficult
to establish a general synthetic method for preparing a
desired isomer with a good selectivity due to variation in
an anomer selectivity between a/ß anomers owing to
influence of a functional group adjacent to 1-position.
For achieving selectivity and a good yield, the presence
of 2-acetoxy or acetamlno group is essential. However,
since 2-deoxysaccharide is unstable, these synthetic
processes may be limited to a considerably narrow
application range. Thus, it is difficult to control
anomer selectivity so that column chromatography
purification is required, leading to a poor yield (Chem.
Zvesti, Vol.28(1), p.115 (1974); Izv. Akad. Nauk SSSR,
Ser. Khim., Vol.8, p.1843 (1975)).
Of course, there Jiave been no reports for chemical
preparation of a 1-phosphorylated 2-deoxyfuranose which
is more unstable than a 1-phosphorylated 2-deoxypyranose,
resulting in more difficult selectivity control.
In terms of 6), preparation of a nucleoside itself
is difficult except a quite limited type of
rebonucleosides such as inosine. A limited type of 1-
phosphorylated saccharide derivatives such as ribose-1-
phosphate can be, therefore, prepared. in addition,
since a nucleoside itself as a starting material is
expensive, the process is not satisfactory in its cost.
As described above, the term "nucleoside
phosphorylase" is a generic name for enzymes capable of
phosphorolysis of an N-glycoside bond in a nucleoside in
the presence of phosphoric acid, which catalyze a
reaction represented by the following equation:
Nucleoside + Phosphoric acid (salt) ? Base + 1-
Phosphorylated saccharide derivative
The enzymes which may be generally categorized into
two groups of purine nucleoside phosphorylases and
pyrimidine nucleoside phosphorylases, are widely
distributed in the living world; they are present in
tissues of mammals, birds and fish; yeasts; and bacteria.
The enzyme reaction is reversible and there have been
disclosed methods for synthesis of a variety of
nucleosides utilizing a reverse reaction; for syntheses
of thymidine (thymine, adenine or guanine) (JP-A 01-
104190), 2'-deoxyadenosine (JP-A 11-137290) or 2' -
deoxyguanosine (JP-A 11-137290) from 2'-deoxyribose 1-
phosphate and a nucleic-acid base.
Furthermore, Agric. Biol. Chem., Vol.50 (1),
pp.121-126 (1986) has described a process where by a
reaction using a purine nucleoside phosphorylase from
Enterobacter aerogenes in the presence of phosphoric
acid, inosine is decomposed into ribose 1-phosphate and
hypoxanthine and the former isolated using an ion-
exchange resin and l,2,4-triazole-3-carboxamide are also
treated with a purine nucleoside phosphorylase from
Enterobacter aerogenes to prepare ribavirin as an
antiviral agent.
However, as described above, an industrial process
for producing a 1-phosphorylated saccharide derivative
has not been established, and thus an industrial process
for preparation of a universally useful nucleoside
utilizing a reverse reaction of a nucleoside
phosphorylase has been also not established.
Furthermore, since the reaction for forming a
nucleoside from 1-phosphorylated saccharide derivative
and a base utilizing the reverse reaction of the enzyme
is reversible, there is a technical drawback that an
inversion rate cannot be improved.
SUMMARY OF THE INVENTION
An objective of this invention is to provide a
highly universal and anomer-selective process for
preparing 1-phospholyrated saccharide derivative which
is not influenced by difference in a saccharide skeleton
such as furanose and pyranose, presence of a substituent
such as a deoxysaccharide or a saccharide type, i.e.,
natural or synthetic.
Another objective of this invention is to provide a
highly universal process for producing a nucleoside by
treating a 1-phosphorylated saccharide derivative and a
nucleic-acid base with a nucleoside phosphorylase and a
method for improving an inversion rate for the
nucleoside in the reaction.
In other words, the ultimate objective of this
invention is to provide a process for producing a highly
pure nucleoside with a lower cost by achieving the first
and the second objectives above.
We have intensely made attempts for achieving the
first objective. Finally, we have found that a 1-
phosphorylated saccharide derivative is present in an
equilibrium with an anomer and a dimer of the 1-
pohsphorylated saccharide derivative under certain
conditions and that the conditions may be adjusted to
allow only a desired anomer to be precipitated as
crystals so that the equilibrium may be displaced toward
the preferable direction to provide the desired anomer
with good selectivity and a high yield. Thus, based on
the findings, we have achieved this invention.
Specifically, this invention encompasses the
following embodiments.
(1) A process for selectively preparing either a or
ß isomer of a 1-phosphorylated saccharide derivative
monomer comprising the steps of phosphorolyzing and
isomerizing an anomer mixture of a 1-phosphorylated
saccharide derivative to give a and ß isomers of the 1-
phosphorylated saccharide derivative monomer and
selectively crystallizing one of these isomers to
displace the equilibrium between these anomers.
(2) A process for selectively preparing either a or
ß isomer of a 1-phosphorylated saccharide derivative
monomer comprising the steps of phosphorolyzing and
isomerizing an anomer mixture of a 1-phosphorylated
saccharide derivative represented by formula (1):
where Rl and R2 independently represents hydrogen,
methyl, protected hydroxymethyl or protected carboxyl;
R3 represents acyl; R4 represents a protective group for
hydroxy; X represents halogen, alkoxy or alkylthio; W
represents oxygen or sulfur; Z represents oxygen, sulfur
or optionally substituted carbon; m represents an
integer of 1 to 3; n represents 0 or 1; p and q
represents an integer of 0 to 4; and r represents 0 or
1; provided that p, q, r and n meet the conditions of
is carbon, to give a and ß isomers of the 1-
pnosphorylated saccharide derivative monomer and
selectively crystallizing one of these isomers to
displace the equilibrium between these anomers:
(3) A process for preparing a 1-phosphorylated
saccharide derivative monomer represented by formula
(3):
wherein R1 and R2 independently represents hydrogen,
methyl, hydroxymethyl or carboxyl; R3 represents
hydrogen or acyl; and X, W, Z, n, p, q and r are as
defined for formula (1).. comprising the steps of
phosphorolyzlng and isomerizing an anomer mixture of a
1-phosphorylated saccharide derivative represented by
formula (1) to give a and 0 isomers of the 1-
phosphorylated saccharide derivative monomer;
selectively crystallizing one of these isomers to
displace the equilibrium between these anomers; and then
removing the protective group represented by r4
(4) A trimer, diner or monomer of a 1-
phosphorylated saccharide derivative represented by
wherein R1 and R2 independently represents hydrogen,
methyl, hydroxymethyl protected with substituted benzoyl
or protected carboxyl; R4 represents hydrogen or a
protective group for hydroxy; and R3, X, W, Z, m, n, p,
q and r are as defined for formula (1), or salts thereof.
(5) A 1-phosphorylated saccharide derivative
monomer represented by formula (5):
wherein p and q represents an integer of 0 to 3; r
represents 0 or 1; and R1, R2, R3. R4.. X, W and Z are as
defined for formula (1); provided that p, q and r meet
the conditions of p+q+r = 3 when Z is oxygen or sulfur
and of p+q+r = 5 when Z is carbon, or salts thereof.
(6) A 1-phosphorylated saccharide derivative
wherein R1 and R2 independently represents hydrogen,
methyl, hydroxymethyl or carboxy; and R3, X, W, Z, n, p,
g and r are as defined for formula (1), or salts thereof.
(7) A 1-phosphorylated saccharide derivative
monomer represented by formula (7):
wherein p and g represents an integer of 0 to 3; r
represents 0 or 1; and R1, R2, R3, r4, X, W and Z are as
defined for formula (1); provided that p, g and r meet
the conditions of p+r = 1, q = 2-2x(p+r) when Z is
oxygen or sulfur and of p+r = 2, q = 4-2x(p+r) when Z is
carbon, or salts thereof.
(8) A process for preparing a 1-phosphorylated
saccharide represented by formula (20):
wherein R11 represents protected hydroxymethyl and
R14 represents a protective group for hydroxy,
comprising the steps of treating a compound represented
by formula (18):
wherein R11 and R14 are as defined above, with
phosphoric acid in the presence of a base to give an
anomer mixture of a 1-phosphorylated saccharide
derivative represented by formula (19):
wherein R11 and R14 are as defined above and m is as
defined in Claim 2; phosphorolyzing and isomerizing the
mixture; and displacing the equilibrium between the
anomer isomers by selectively crystallizing an a-isomer
formed.
(9) A process for preparing 2-deoxy-a-D-ribose-1-
phosphate, comprising the steps of treating a compound
represented by formula (18):
wherein R11 represents protected hydroxyraethyl and
R14 represents a protective group for hydroxy, with
phosphoric acid in the presence of a base to give an
anomer mixture of a 1-phosphorylated saccharide
derivative represented by formula (19):
wherein R11 and R14 are as defined above and m is as
defined in Claim 2; phosphorolyzing and isomerizing the
mixture; displacing the equilibrium between the anomer
isomers by selectively crystallizing an a-isomer formed
to give the a-isomer; and then removing the protective
group.
We have intensely attempted for achieving the
second objective and thus have established a highly
universal process for preparing a nucleoside by
utilizing a reverse reaction of nucleoside
phosphorylases widely distributed in the living world in
combination with the above preparation processes for a
1-phosphorylated saccharide derivative. We have further
found that a metal cation capable of forming a water-
insoluble salt with a phosphate ion may be present to
allow a phosphate ion as a byproduct in the reaction to
be precipitated as a water-insoluble salt, resulting in
displacement of the reaction equilibrium toward the
direction for nucleoside production and thus improvement
in a reaction yield. Thus, we have achieved this
invention providing a process for preparing a highly
pure nucleoside with a lower cost.
This invention based on the above findings
encompasses the following embodiments.
(10) A process for preparing a nucleoside
represented by formula (8):
wherein B is a base independently selected from the
group consisting of pyriraidine, purine, azapurine and
deazapurine optionally substituted by halogen, alkyl,
haloalkyl, alkenyl, haloalkenyl, alkynyl, amino,
alkylamino, hydroxy, hydroxyamino, aminoxy, alkoxy,
mercapto, alkylraercapto, aryl, aryloxy or cyano; and R1,
R2, R3, X, W, Z, n, p, q and r are as defined for
formula (1), comprising
the first procedure in the above (3) for preparing
a 1-phosphorylated saccharide derivative monomer
comprising the steps of phosphorolyzing and isomerizing
an anomer mixture of a 1-phosphorylated saccharide
derivative to give a and 0 isomers of the 1-
phosphorylated saccharide derivative monomer;
selectively crystallizing one of these isomers to
displace the equilibrium between these anomers; and then
removing the protective group represented by R4 and
the second procedure of conducting an exchange
reaction of the phosphate group in the 1-phosphorylated
saccharide derivative obtained in the first procedure
with a base by the action of a nucleoside phosphoxylase.
(11) A process for preparing a nucleoside
represented by formula (9):
wherein B is as defined for formula (8); and R1, R2.
R3, R4, X, W, Z, n, p, q and r are as defined for
formula (1), comprising an exchange reaction of the
phosphate group in the 1-phosphorylated saccharide
derivative monomer in the above (6) with a base by the
action of a nucleoside phosphoxylase.
(12) A process for preparing a nucleoside
represented by formula (10):
wherein B is as defined for formula (8); and R1, R2.
R3, r4, X, W, Z, p, q and r are as defined for formula
(1). comprising an exchange reaction of the phosphate
group in the 1-phosphorylated saccharide derivative
monomer in the above (7) with a base by the action of a
nucleoside phosphorylase.
(13) A process for preparing a nucleoside
represented by formula (21):
wherein B is as defined for formula (8) in Claim 11,
comprising
the first procedure of preparing 2-deoxy-a-D-
ribose-1-phosphate in the above (12) where R1 is
hydroxymethyl, R2 is hydrogen, p and r are 0, and X is
fluorine; and
the second procedure of conducting an exchange
reaction of the phosphate group in the 1-phosphorylated
saccharide derivative obtained in the first procedure
with a base by the action of a nucleoside phosphorylase.
In the embodiments of the above (10) to (13), a
nucleoside phosphorylase may be at least one selected
from the group consisting of purine nucleoside
phosphorylase (EC2.4.2.1), guanosine nucleoside
phospborylase ((EC2.4.2.15), pyrimldine nucleoside
phosphorylase (EC2.4.2.2), uridine nucleoside
phosphorylase (EC2.4.2.3), thymidine nucleoside
phosphorylase (EC2.4.2.4) and deoxyuridine nucleoside
phosphorylase (EC2.4.2.23).
A nucleoside phosphorylase activity may be obtained
using a microorganism expressing at least one nucleoside
phosphorylase selected from the group consisting of
purine nucleoside phosphorylase (EC2.4.2.1), guanosine
nucleoside phosphorylase (EC2.4.2.15), pyrimldine
nucleoside phosphorylase (EC2.4.2.2), uridine nucleoside
phosphorylase (EC2.4.2. 3), thymidine nucleos ide
phosphorylase (EC2.4.2.4) and deoxyuridine nucleoside
phosphorylase (EC2.4.2.23).
In the embodiments of the above (10) to (13), a
metal cation capable of forming a water-insoluble salt
with a phosphate ion may be present in the reaction
solution during the exchange reaction of a phosphate
group in the 1-phosphorylated saccharide derivative
monomer with a base by the action of a nucleoside
phosphorylase.
The metal cation capable of forming a water-
insoluble salt with the phosphate ion in the embodiments
of the above (10) to (13) may be at least one metal
cation selected from the group consisting of calcium.
barium, aluminum and magnesium ions.
Furthermore, this invention encompasses a compound
represented by any of formulas (11) to (13) and (20).
That is, this invention also encompasses:
a synthetic nucleoside, which is not naturally
produced represented by formula (11):
wherein B, Rx, R2, R3, R4, X, W, Z, n, p, q and r
are as defined for formulas (1) and (8) or its salt,
excluding trifluorothymidine, ribavirin, orotidine,
uracil arabinoslde, adenine arabinoside, 2-methyl-
adenine arabinoslde, 2-chloro-hypoxanthine arabinoside,
thioguanine arabinoside, 2,6-diaminopurine arabinoside,
cytosine arabinoside, guanine arabinoside, thymine
arabinoside, enocitabine, gemcitabine, azidothymidine,
idoxuridine, dideoxyadenosine, dldeoxyinosine,
dideoxycytidine, didehydrodeoxythymidine,
thiadideoxycytldlne, sorivudine, 5-methyluridine,
virazole, thioinosine, tegafur, doxifluridine, bredinin,
nebularine, allopurinol uracil, 5-fluorouracil, 2'-
aminouridine, 2'-aminoadenosine, 2'-aminoguanidine, 2-
chloro-2'-amlnoinosine, DMDC and FMDC;
a synthetic nucleoside, which is not naturally
produced represented by formula (12):
wherein B, R1, R2, R3, R4, X, W, Z, n, p, q and r
are as defined for formulas (1) and (8) or its salt,
excluding trifluorothymidine, ribavirin, orotidine,
uracil arabinoside, adenine arabinoside, 2-methyl-
adenine arabinoside, 2-chloro-hypoxanthine arabinoside,
thioguanine arabinoside, 2,6-diaminopurine arabinoside,
cytosine arabinoside, guanine arabinoside, thymine
arabinoside, enocitabine, gemcitablne, azidothymidine,
idoxuridine, dideoxyadenosine, dideoxyinosine,
dideoxycytidine, didehydrodeoxythymidine,
thiadldeoxycytidine, sorivudine, 5-methyluridine,
virazole, thioinosine, tegafur, doxifluridine, bredinin,
nebularine, allopurinol uracil, 5-fluorouracil, 2'-
aminouridine, 2'-aminoadenosine, 2'-aminoguanidine, 2-
chloro-2'-amlnoinosine. DMDC and FMDC;
wherein B, R1, R2, R3, R4, X, W, Z, n, p, q and r
are as defined for formulas (1) and (8) or its salt,
excluding trifluorothyraidine, ribavirin, orotidine,
uracil arabinoside, adenine arabinoside, 2-methyl-
adenine arabinoside, 2-chloro-hypoxanthine arabinoside,
thioguanine arabinoside, 2,6-diaminopurine arabinoside,
cytosine arabinoside, guanine arabinoside, thymine
arabinoside, enocitabine, gemcitabine, azidothymidine,
idoxuridine, dideoxyadenosine, dideoxyinosine,
dideoxycytidine, didehydrodeoxythymidine,
thiadldeoxycytidine, sorivudine, 5-methyluridine,
virazole, thioinosine, tegafur, doxifluridine, bredinin,
nebularine, allopurinol uracil, 5-fluorouracil, 2'-
aminouridine, 2'-aminoadenosine, 2'-aminoguanidine, 2 -
chloro-2'-aminolnosine, DMDC and FMDC; and
a 1-phosphorylated saccharide represented by
formula (20):
wherein R11 and R14 are as defined for formula (18),
or its salt.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
This invention will be described in detail.
Saccharides which may used in this invention
include, but not limited to, residues derived from D-
and 1-type natural monosaccharides including 6-
deoxysaccharides such as fucose, rhamnose, digitoxose,
oleandrose and quinovose, hexoses such as allose,
altrose, glucose, mannose, gulose, idose, galactose and
talose, pentoses such as ribose, arabinose, xylose and
lyxose, tetroses such as erythrose and threose,
aminosaccharides such as glucosamine and daunosamine,
uronic acids such as glucuronic acid and galacturonic
acid, ketoses such as psicose, fructose, sorbose,
tagatose and pentulose, and deoxysaccharides such as 2-
deoxyribose; residues derived from synthetic pyranose
and furanose saccharides; and saccharide residue
derivatives in which hydroxy and/or amino groups in any
of the above residues are protected or acylated or
saccharides having a halogenated saccharide residue in
which hydroxy is replaced with halogen such as fluorine.
In this invention, a 1-phosphorylated saccharide
derivative refers to a saccharide derivative in which
among residues derived from natural or synthetic
monosaccharide, 1-hydroxy is phosphorylated. Unless
otherwise indicated, it may include a monomer, dimer or
trimer or a mixture thereof, where there are no
restrictions to its mixture ratio.
A protective group in terms of "protected
hydroxymethyl" and "a protective group of hydroxy" means
that which may be removed by an appropriate chemical
process such as hydrogenolysis, hydrolysis and
photolysis, including formyl, acyl, silyl, alkyl,
aralkyl, carbonyl, preferably formyl, aliphatic acyl,
aromatic acyl, silyl, alkoxyalkyl, halogenated alkyl,
aralkyl, alkoxycarbonyl and aralkyloxycarbonyl.
Aliphatic acyl may be alkylcarbonyl and halogenated
lower alkylcarbonyl.
Alkyl may be alkoxyalkyl such as methoxyethyl,
ethoxymethyl, 2-methoxyethyl and 2-methoxyethoxymethyl;
halogenated alkyl such as 2,2,2-trichloroethyl; or lower
alkyl substituted with aryl such as benzyl, a-
naphthylmethyl, ß-naphthylmethyl, diphenylmethyl and
trlphenylmethyl.
Among these, aliphatic acyl, aromatic acyl and
aralkyl are preferable; 4-toluoyl, 4-chlorobenzoyl and
benzyl are more preferable. A protective group in
terms of "protected carboxyl" in R1 and R2 refers to
that which may be removed by an appropriate chemical
process such as hydrogenolysis, hydrolysis and
photolysis, including preferably lower alkyl such as
methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl,
sec-butyl and tert-butyl; silylated lower alkyl such as
2-(trlmethylsilyl)ethyl and 2-(triethylsilyl)ethyl; or
the above aralkyl or alkoxyalkyl, more preferably methyl,
tert-butyl or benzyl.
Halogen in terms of X refers to fluorine, chlorine,
bromine or iodine.
Alkoxy and alkylthio in terms of X may be alkoxy
and alkylthio having the above lower alkyl, aralkyl or
alkoxyalkyl, preferably methoxy, methoxyethoxy or
methylthio.
Optionally substituted carbon in terms of Z refers
to carbon having one or two of the substituent
represented by the formula (Xq and NHR3) or when having
no substituents, carbon having hydrogen atoms.
Acyl in terms of R3 may be the above aliphatic acyl,
aromatic acyl, alkoxycarbonyl or aralkyloxycarbonyl, or
lower-alkanesulfonyl such as methanesulfonyl and
trifluoromethanesulfonyl or arylsulfonyl such as
benzenesulfonyl and p-toluenesulfonyl; preferably,
aliphatic acyl, aromatic acyl or lower-alkanesulfonyl;
specifically, acetyl, trifluoroacetyl, benzoyl and
methanesulfonyl. When more than one of NHR3 are used as
a substituent, R3s in individual NHR3 independently
represent any of the above radicals.
A protective group in "protected hydroxymethyl" and
a protective group for hydroxy" in terms of R4, R11 and
R14 may be selected from those described for R1 and R2.
Saccharide residues having a structure represented
by any of formulas (1) to (17) may be preferably, but
not limited to, those derived from a natural
monosaccharide described above, those derived from a
synthetic saccharide, derivatives from the saccharide
residues or halogenated saccharide residues, as
described above.
Salts of a compound represented by any of formulas
(4) to (7) may be those formed by a phosphate radical in
the compound. Examples of such a salt include alkali
metal salt such as sodium, potassium and lithium salts;
alkaline earth metal salt such as magnesium, calcium and
barium salts; metal salt such as aluminum and iron
salts; ammonium salt; or alkylamine salt such as primary,
secondary and tertiary alkyl amine salts.
Primary amine herein may be alkylamine such as
methylamine, ethylamine, propylamine, lsopropylamine,
butylamine, hexylamine and octylamine; cycloalkylamine
such as cyclohexylamine; or benzylamine.
Secondary amine may be dialkylamine such as
diethylamine, diisopropylamine, dibutylamine,
dihexylamine and dioctylamine; dicycloalkylamine such as
dicyclohexylamine; or cyclic amine such as piperidine,
morpholine and N-methylpiperadine.
Tertiary amine may be tertiary-alkylamine such as
trimethylamine, triethylamine, tripropylamine, N-
ethyldlisopropylamine, tributylamine, trihexylamine,
trioctylamine, N-ethyldicyclohexylamine, N-
methylpiperidine, N-methylmorpholine and N,N,N',N'-
tetramethylethylenediamine; aniline compound such as
aniline, N,N-dlmethylaniline, N,N-diethylaniline, N,.N-
dibutylaniline and N,N-dioctylaniline; pyridine compound
such as pyridine, 2,6-dimethylpyridine, 2,4,6-lutidine
and nicotinamide; amino acid such as glycine, alanine,
proline, lysine, arginine and glutamine; or optically
active amine such as cinchonidlne, 1-(1-
naphthyl)ethylamine and 1-phenylethylamine, all of which
include monovalent and bivalent salts.
A compound represented by any of formula (4) to (7)
of this invention may absorb moisture to have adsorbed
water or become a hydrate, all of which may be
encompassed by this invention.
An anomer mixture of a 1-phosphorylated saccharide
derivative according to this invention may be prepared
by, but not limited to, a reaction represented by
reaction formula (I):
Reaction formula (I)
In this formula, R1, R2, R3, R4, X, W, Z, m, n. p. q
and r are as defined for formula (1), and Y represents
fluorine, chlorine, bromine or iodine. When m is 1, 2
or 3, phosphoric acid tri-, di- or mono-ester is
provided, respectively. These are referred to as 1-
phosphorylated saccharide derivative trimer, 1-
phosphorylated saccharide derivative dimer and 1-
phosphorylated saccharide derivative monomer,
respectively. Furthermore, 1-phosphorylated saccharide
derivative trimer, 1-phosphorylated saccharide
derivative dimer and 1-phosphorylated saccharide
derivative monomer are collectively referred to as a 1-
phosphorylated saccharide derivative, for which there
are no restrictions to its mixture ratio.
A preferable phosphoric acid may be, but not
limited to, one with a lower water content such as
orthophosphoric acid.
There are no restrictions to a base as long as it
does not inhibit the reaction and functions as a
deoxidizer. Preferable inorganic bases include
carbonates and hydroxides of alkali and alkaline earth
metals. Preferable organic bases include tertiary
alkylamines, anilines, pyridines and optically active
amines.
A dehydrating agent may be used when moisture from
a solvent or an additive adversely affects the reaction.
There are no restrictions to a dehydrating agent as long
as it has adequate adsorptivity or reactivity with
water; preferably molecular sieves and phosphorus
pentoxide.
The reaction is generally conducted in the presence
of a solvent. There are no restrictions to a solvent as
long as it does not inhibit the reaction and dissolve
starting materials to some degree. Solvents which may
be used include aliphatic hydrocarbons such as hexane
and heptane; aromatic hydrocarbons such as benzene,
toluene, xylene and anisole; halogenated hydrocarbons
such as methylene chloride, chloroform, carbon
tetrachloride, dichloroethane, chlorobenzene and
dichlorobenzene; esters such as ethyl formate, ethyl
acetate, propyl acetate, n-butyl acetate and diethyl
carbonate; ethers such as diethyl ether, diisopropyl
ether, tetrahydrofuran, dioxane, dimethoxyethane and
diglyme; nitriles such as acetonitrile, propionitrile
and isobutylnitrile; amides such as formamide, N,N-
dimethylformamide, N.N-dimethylacetamide, N-methyl-2-
pyrrolidone, N-methylpyrrolidinone and N,N-dimethyl-2-
imidazolydinone; ketones such as acetone, 2-butanone,
methyl isopropyl ketone and methyl isobutyl ketone; and
a mixture of two or more selected therefrom.
There are no restrictions to a reaction
temperature; generally -80 °C to 60 °C, preferably -10 °C
to 25 °C.
A reaction period may vary depending on many
factors such as starting materials, reagents, the type
of a solvent and a reaction temperature; generally 1 min
to 24 hours, preferably 10 min to 2 hours for completing
the reaction.
There are no restrictions to a ratio of a
saccharide derivative (14) to phosphoric acid; the
reaction is generally conducted with a ratio of compound
(14) : phosphoric acid = 1:10 to 3:1. in this case, the
product (1) may be a mixture of the compounds whose
saccharide residue number (i.e., m) coupled with
phosphoric acid is 1, 2 or 3, depending on the ratio of
compound (14) : phosphoric acid.
Furthermore, a 1-phosphorylated saccharide
derivative (16a) or (16b) with either a- or ß-form may
be prepared by a reaction represented by reaction
formula (II):
In this formula, R1, R2. R3. R4, X, W, Z. m. n, p, q
and r are as defined for formula (1).
According to this preparation process, the 1-
phosphorylated saccharide derivative represented by
formula (15) may be a monomer, dimer or trimer or a
mixture thereof in any mixture ratio because they may be
converted into the 1-phosphorylated saccharide
derivative represented by formula (16) in the reaction
system.
A preferable phosphoric acid may be, but not
limited to, one with a lower water content such as
orthophosphoric acid.
A base is important for forming a salt with the
phosphate group in compound (16) to selectively
crystallize one of a- and ß-compounds, (16a) or (16b).
The most suitable base, may be selected in the light of a
solvent used in the reaction; preferably, the above
inorganic bases, tertiary alkylamines, anilines,
pyridines, amino acids and optically active amines, and
salts formed include monovalent and bivalent salts.
A dehydrating agent may be used when moisture from
a solvent or an additive adversely affects the reaction.
There are no restrictions to a dehydrating agent as long
as it has adequate adsorptivity or reactivity with
water; preferably molecular sieves and phosphorus
pentoxide.
The reaction is generally conducted in the presence
of a solvent. There are no restrictions to a solvent as
long as it does not inhibit the reaction, dissolve
starting materials to some degree and promotes selective
crystallization of one of the a- and ß-forms, (16a) or
(16b), generated by salt formation of the phosphate
group in compound (16), including the above aliphatic
hydrocarbons, aromatic hydrocarbons, halogenated
hydrocarbons, esters, ethers, nitriles, amides, ketones
and a mixture of two or more selected therefrom.
There are no restrictions to a reaction temperature
as long as it accelerates the equilibrium reaction
between compounds (15) and (16) for promoting selective
crystallization of one of the a- and ß-forms, (16a) or
(16b), generated by salt formation of the phosphate
group in compound (16); generally -80 °C to 60 °C,
preferably -10 °C to 25 °C.
A reaction period may vary depending on many
factors such as starting materials, reagents, the type
of a solvent and a reaction temperature; generally 3
hours to 1 week, preferably 6 hours to 24 hours for
completing the reaction.
There are no restrictions to a ratio of a
saccharide derivative (1) to phosphoric acid; the
reaction is generally conducted with a ratio of compound
(1) : phosphoric acid = 1:10 to 3:1, where the pH of the
reaction system is generally 1 to 7, suitably in an
acidic range from 1 to 4.
The 1-phosphorylated saccharide derivative (16a) or
(16b) with either a- or ß-form may be isolated as a
phosphate with a base other than that used in the
reaction system by a salt-exchange reaction.
Bases which may be herein used include the above
inorganic bases, primary alkylamines, secondary
alkylamines, tertiary alkylamines, anilines, pyridines,
amino acids and optically active amines, and salts
formed include monovalent and bivalent salts.
The protective group may be removed by reaction
formula (III) to prepare a 1-phosphorylated saccharide
derivative (17a) or (17b).
In this formula. R1, R2, R3, R4. X, W, Z, n, p, q
and r are as defined for formula (1); R1' and R2'
independently represent hydrogen, methyl, hydroxymethyl
or carboxyl; and R3' represents hydrogen or acyl.
When using the above aliphatic acyl, aromatic acyl
or alkoxy carbonyl as a protective group for
hydroxymethyl in R1 and R2 or hydroxy in R4, or using the
above lower alkyl as a protective group for carboxyl in
R1 and R2 in compound (16a) or (16b), it may be removed
by treating the compound with a base in an aqueous
solvent. Bases which may be used include preferably
alkali metal carbonates such as sodium carbonate and
potassium carbonate; alkali metal hydroxides such as
lithium hydroxide, sodium hydroxide and potassium
hydroxide; ammonium hydroxides such as ammonium
hydroxide and tetra-n-butylammonium hydroxide; and the
above inorganic bases, primary alkylamines, secondary
alkylamines and tertiary alkylamines.
Solvents which may be used include, with no
restrictions, those used in a common hydrolysis;
preferably water; alcohols such as methanol, ethanol, n-
propanol and isopropanol; and the above ethers. A
reaction temperature and a reaction period vary, with no
restrictions, depending on many factors such as starting
materials and a base used; generally the reaction may be
completed at -10 °C to 100 °C for 1 hour to 5 days. The
protective group R3 may be left or simultaneously
removed as appropriate by adjusting a reaction
temperature, a reaction period and the equivalent values
of reagents.
When using the above aralkyl or aralkyloxycarbonyl
as a protective group for hydroxymethyl in R1 and R2 or
hydroxy in R4 or using the above aralkyl as a protective
group for carboxy in R1 and R2 in compound (16a) or
(16b), they may be removed by, for example, catalytic
hydrogenatlon using a metal catalyst.
The catalyst may be preferably selected from
palladium-carbon, Raney nickel, platinum oxide, platinum
black, rhodium-aluminum oxide, triphenylphosphine-
rhodlum chloride and palladium-barium sulfate. There
are no restrictions to a reaction pressure. Generally,
a solvent used may be any of those used in a common
hydrolysis with no restrictions. it may be preferably
selected from water; alcohols such as methanol, ethanol,
n-propanol and isopropanol; the above ethers; and the
above esters. A reaction temperature and a reaction
period vary, with no restrictions, depending on many
factors such as starting materials and a base used;
generally the reaction may be completed at -10 °C to 100
°C for 1 hour to 5 days. The protective group R3 may be
generally left.
When using the above silyl as a protective group
for hydroxymethyl in R1 and R2 or hydroxy in R4 or using
the above silylated lower alkyl as a protective group
for carboxy in R1 and R2 in compound (16a) or (16b),
they may be removed by, for example, using a compound
which can generate fluoride anion such as tetra-n-
butylammonium fluoride.
There are no restrictions to a solvent as long as
it does not inhibit the reaction; for example, the above
ethers may be used. A reaction temperature and a
reaction period vary, with no restrictions, depending on
many factors such as starting materials and a base used;
generally the reaction may be completed at -10 °C to 50
°C for 10 min to 10 hours. The protective group R3 may
be generally left.
In removing any protective group, a phosphate group
in a product is obtained as a salt with a base present
in a reaction system. The salt may be, if necessary,
converted into a salt with another base. in such a case,
a base used may be selected from the above inorganic
bases, primary alkylamines, secondary alkylamines,
tertiary alkylamines, anilines, pyridines, amino acids
and optically active amines, and salts formed include
monovalent and bivalent salts.
A 1-phosphorylated saccharide derivative as used
herein is a saccharide or its derivative in which a
phosphoric acid moiety is coupled at 1-position via an
ester linkage.
It may be specifically represented by formula (6):
wherein R1 and R2 independently represent hydrogen,
methyl, hydroxymethyl or carboxy; R3, X, W, Z, n, p. q
and r are as defined for formula (4).
Typical examples include, but not limited to,
ribose-1-phosphate, 2-deoxyribose-1-phosphate, 2,3-
dideoxyribose-1-phosphate and arabinose-1-phosphate, but
any derivative may be used without distinction as long
as it can be obtained by any of the above highly
universal and anomer-selective preparation processes.
Examples of a saccharide derived from a natural
product which constitutes a 1-phosphorylated saccharide
derivative include, but not limited to, aldopentoses
such as D-arabinose, 1-arablnose, D-xylose, 1-lyxose and
D-ribose; ketopentoses such as D-xylose, 1-xylose and D-
ribulose; aldohexoses such as D-galactose, 1-galactose,
D-glucose, D-talose and D-mannose; ketohexoses such as
D-tagatose, 1-sorbose, D-psicose and D-fructose;
deoxysaccharides such as D-2-deoxyribose, D-2,3,-
dideoxyribose, D-fucose, 1-fucose, D-rharanose, 1-
rhamnose, D-fucopyranose, 1-fucopyranose. D-
rhamnofuranose, 1-rhamnofuranose, D-allomethylose, D-
quinovose, D-antiallose, D-talomethylose. 1-
talomethylose, D-digitalose, D-digitoxose, D-cymarose,
tyvelose, abequose, paratose, colitose and ascarilose;
aminosaccharides such as glucosamine and daunosamine;
and uronic acids such as glucuronic acid and
galacturonic acid.
There will be described a process for preparing a
nucleoside according to this invention. A base used in
this process is a natural or synthetic base selected
from pyrimidine, purine, azapurine and deazapurine,
which may be substituted with halogen, alkyl, haloalkyl,
alkenyl, haloalkenyl, alkynyl, amino, alkylamlno,
hydroxy, hydroxyamino, aminoxy, alkoxy, mercapto,
alkylinercapto, aryl, aryloxy and/or cyano.
Examples of halogen as a substituent include
chlorine, fluorine, bromine and iodine. Examples of
alkyl include lower alkyls with 1 to 7 carbon atoms such
as methyl, ethyl and propyl. Examples of haloalkyl
include those having an alkyl with 1 to 7 carbon atoms
such as fluoromethyl, difluoromethyl, trifluoromethyl,
bromomethyl and bromoethyl. Examples of alkenyl include
those with 2 to 7 carbon atoms such as vinyl and allyl.
Examples of haloalkyl include those having alkenyl with
2 to 7 carbon atoms such as bromovinyl and chlorovinyl.
Examples of alkynyl include those with 2 to 7 carbon
atoms such as ethynyl and propynyl. Examples of
alkylamlno include those having alkyl with 1 to 7 carbon
atoms such as methylamino and ethylamino. Examples of
alkoxy include those with 1 to 7 carbon atoms such as
methoxy and ethoxy. Examples of alkylmercapto include
those having alkyl with 1 to 7 carbon atoms such as
methylmercapto and ethylmercapto. Examples of aryl
include phenyl; alkylphenyls having alkyl with 1 to 5
carbon atoms such as methylphenyl and ethylphenyl;
alkoxyphenyls having alkoxy with 1 to 5 carbon atoms
such as methoxyphenyl and ethoxyphenyl;
alkylaminophenyls having alkylamino with 1 to 5 carbon
atoms such as dimethylaminophenyl and
diethylamlnophenyl; and halogenophenyls such as
chlorophenyl and bromophenyl.
amino-6-hydroxy-8-azapurine, 6-amino-7-deazapurine, 6-
araino-1-deazapurine and 6-amino-2-azapurine.
A nucleoside phosphorylase is a generic name for
enzymes capable of phosphorolysis of an N-glycoside bond
in a nucleoside in the presence of phosphoric acid and
this invention utilizes its reverse reaction. An enzyme
used in the reaction may be of any type or origin as
long as it has an activity of forming a desired
nucleoside from a corresponding 1-phosphorylated
saccharide derivative and a base. The enzymes may be
generally categorized into two types, purine and
pyrimidine types. Examples of a purine type enzyme
include purine nucleoside phosphorylase (EC2.4.2.1) and
guanosine nucleoside phosphorylase (EC2.4.2.15). .
Examples of a pyrimidine type enzyme include pyrimidine
nucleoside phosphorylase (EC2.4.2.2), uridine nucleoside
phosphorylase (EC2.4.2.3), thymidine nucleoside
phosphorylase (EC2.4.2.4) and deoxyuridine nucleoside
phosphorylase (EC2.4.2.23).
A microorganism expressing a nucleoside
phosphorylase in this invention may be, with no
restrictions, any microorganism expressing at least one
nucleoside phosphorylase selected from the group
consisting of purine nucleoside phosphorylase
(EC2.4.2.1), guanosine nucleoside phosphorylase
(EC2.4.2.15), pyrimidine nucleoside phosphorylase
Preferable examples of such a microorganism include
strains belonging to Nocardia, Microbacterium,
Corynebacterium, Brevibacterium, Cellulomonas,
Flabobacterium, Kluyvere, Micobacterium, Haemophilus,
Micoplana, Protaminobacter. Candida, Saccharomyces,
Bacillus, thermophile Bacillus, Pseudomonas, Micrococcus,
Hafnia, Proteus, Vibrio, Staphyrococcus,
Propionibacterium, Sartina, Planococcus, Escherichia,
Kurthia, Rhodococcus. Acinetobacter, Xanthobacter,
Streptomyces, Rhizobium, Salmonella, Klebsiella,
Enterobacter, Erwinia, Aeromonas, Citrobacter,
Achromobacter, Agrobacterium, Arthrobacter and
Pseudonocardia.
Recent advance in molecular biology and genetic
engineering has allowed us to analyze molecular-
biological properties, an amino acid sequence and so on
of a nucleoside phosphorylase in the above strain for
obtaining the gene for the protein from the strain, to
constitute a recombinant plasmid in which a control
region required for the gene and its expression is
inserted, to introduce the plasmid into a given host and
to produce a gene recombinant strain expressing the
protein, and these processes have become relatively
easier. in the light of the recent technical level,
such a gene recombinant strain in which a gene for a
nucleoside phosphorylase is introduced in a given host
shall be also included in a microorganism expressing a
nucleoside phosphorylase according to this invention.
A control region required for expression herein may
be a promoter sequence (including an operator sequence
controlling transcription), a ribosome binding sequence
(SD sequence), a transcription termination sequence, or
the like. Examples of a promoter sequence include a trp
operator in a tryptophane operon derived from E. coli; a
lac promoter in a lactose operon; a PL and a PR
promoters derived from lambda phage; a gluconate
synthase promoter (gnt) derived from Bacillus subtilis;
an alkali protease promoter (apr); a neutral protease
promoter (npr); and a amylase promoter (amy). A
uniquely modified and designed sequence such as a tac
promoter may be used. A ribosome linkage sequence may
be, for example, a sequence derived from E. coli or
Bacillus subtilis, but any sequence may be used as long
as it can function in a desired host such as E. coli and
Bacillus subtilis. For example, one can use a consensus
sequence formed by DNA synthesis, that is, a sequence
with more than 4 consecutive bases complementary to 3'-
terminal region in 16S rlbosome RNA. A transcription
termination sequence is not always necessary, but a p-
factor independent terminator such as a lipoprotein
terminator and a trp operon terminator may be used.
Desirably, these control regions on a recombinant
plasmid may be sequentially aligned as follows; from
upstream of 5'-terminal, a promoter sequence, a ribosome
linkage sequence, a nucleoside phosphorylase coding gene
and a transcription termination sequence.
As examples of a plasmid herein, pBR 322, pUC18,
Bluescript II SK(+), pKK223-3 and pSClOl having an
autonomously replicable region in E. coli; pUB110, pTZ4,
pC194, p11, 1 and 105 having an autonomously
replicable region in Bacillus subtilis may be used as a
vector. As examples of a plasmid autonomously
replicable in two or more hosts, pHV14, TRp7, Yep7 and
pBS7 may be used as a vector.
A given host herein may be typically, but not
limited to, Escherichia coli as described in Examples
later, but other strains such as Bacillus sp. including
Bacillus subtilis, yeasts and actinomyces may be used.
Nucleoside phosphorylase activity in this invention
may be obtained from, besides the above strains having
the enzyme activity, a processed material of the strain
exhibiting the enzyme activity and an immobilized
product thereof. A processed material of the strain may
be, for example, acetone-dried strain or a bacterial
debris prepared by an appropriate procedure such as
mechanical destruction, ultrasonic disintegration,
freezing and thawing, pressurization and
depressurization, osmotic pressure method, autolysis,
cel1-wall decomposition and surfactant treatment. If
necessary, the strain may be further purified by
ammonium sulfate precipitation, acetone precipitation or
column chromatography.
In this invention, a metal cation capable of
forming a water-insoluble salt with phosphate ion may be,
without restriction, any metal cation which can form a
water-insoluble salt with phosphate ion as a byproduct
in the reaction and may be precipitated; for example,
calcium, magnesium, barium, iron, cobalt, nickel, copper,
silver, molybdenum, lead, zinc and lithium ions. Among
these, particularly preferable are industrially
universal and safe metal ions which do not adversely
affect the reaction, e.g., calcium, barium, aluminum and
magnesium ions.
A metal cation capable of forming a water-insoluble
salt with phosphate ion in this invention may be
obtained by adding a salt of a metal cation capable of
forming a water-insoluble salt with phosphate ion with
at least one anion selected from chloride, nitride,
carbonate, sulfate, acetate and hydroxyl ions into the
reaction solution. Examples of such a salt include
calcium chloride, calcium nitride, calcium carbonate,
calcium sulfate, calcium acetate, barium chloride,
barium nitride, barium carbonate, barium sulfate, barium
acetate, aluminum chloride, aluminum nitride, aluminum
carbonate, aluminum sulfate, aluminum acetate, calcium
hydroxide, barium hydroxide, aluminum hydroxide,
magnesium hydroxide, magnesium chloride, magnesium
nitride, magnesium carbonate, magnesium sulfate and
magnesium acetate.
Such a metal cation may be present as a salt with a
pentose-1-phosphate in the reaction solution; for
example, ribose-1-phosphate calcium salt, 2-deoxyribose-
1-phosphate calcium salt, 2,3-dldeoxyribose-1-phosphate
calcium salt, arabinose-1-phosphate calcium salt,
ribose-1-phosphate barium salt, 2-deoxyribose-1-
phosphate barium salt, 2,3-dideoxyribose-1-phosphate
barium salt, arabinose-1-phosphate barium salt, ribose-
1-phosphate aluminum salt, 2-deoxyribose-1-phosphate
aluminum salt, 2,3-dideoxyribose-1-phosphate aluminum
salt and arablnose-1-phosphate aluminum salt.
A reaction for preparing a nucleoside compound in
this invention may be conducted under the conditions
such as appropriate pH and temperature and within the
control ranges thereof, depending on a target nucleoside,
a 1-phosphorylated saccharide derivative and a base as
substrates, a nucleoside phosphorylase or a
microorganism exhibiting the activity of the enzyme as a
reaction catalyst, and the type and the properties of a
metal salt added for removing phosphoric acid from the
reaction system; generally at pH 5 to 10 and a
temperature of 10 to 60 °C. If pH is not within the
control range, a reaction inversion rate may be reduced
due to, for example, poor stability of a target product
or substrate, reduction in enzyme activity and failure
to forming a water-insoluble salt with phosphoric acid.
If pH varies in the course of the reaction, an acid such
as hydrochloric acid and sulfuric acid or an alkali such
as sodium hydroxide and potassium hydroxide may be, when
necessary, added at an appropriate timing. The
concentrations of a 1-phosphorylated saccharide
derivative and a base are suitably about 0.1 to 1000 mM.
in terms of a molar ratio between them, a molar ratio of
a base to a 1-phosphorylated saccharide derivative or
its salt may be 1 to 10, preferably 0.95 or less in the
light of a reaction inversion rate.
A metal salt capable of forming a water-insoluble
salt with phosphoric acid added may be added in a molar
ratio of 0.1 to 10, more preferably 0.5 to 5 to a 1-
phosphorylated saccharide derivative used in the
reaction. There are no restrictions to an addition
procedure of the salt, and it may be added in one
portion or portionwise during the reaction. This
invention basically uses water as a solvent, but an
organic solvent such as an alcohol and dinethylsulfoxide
used in a common enzyme reaction may be, if necessary,
added in an appropriate amount. in a reaction with a
higher concentration, a base as a substrate or a
nucleoside as a product may be not be completely
dissolved in the reaction solution. This invention may
be also applied to such a case.
A nucleoside compound produced as described above
may be isolated by a common procedure such as
concentration, crystallization, dissolution,
electrodialysis and adsorption and desorption using an
ion-exchange resin or charcoal.
Examples
This invention will be more specifically described
with reference to, but not limited to Examples.
To a mixture of 1.18 g of orthophosphoric acid in 51 mL
of acetonitrlle were added 2.3 g of tri-n-
butylamine and 5.07 g of molecular sieves 4A, and the
mixture was cooled to 5 °C with stirring. After one
hour, to the mixture was added 5.07 g of 3.5-0-bis(4-
For preparing a sample for analysis, these
compounds were converted into cyclohexylamine salts,
which were then purified by silica gel column
chromatography to provide two anomer isomers (19a) and
(19b) of the title compound (19) from a fraction eluted
with methano1-ethyl acetate (1:10).
O-bis(4-chlorobenzoyl)-2-deoxy-D-ribos-1-yl]phosphate
To a mixture of 1.11 g of orthophosphorlc acid in
49 mL of 2-butanone were added 2.11 g of tri-n-
butylamine and 4.9 g of molecular sieves 4A, and the
mixture was cooled to 5 °C with stirring. To the
mixture was added 4.9 g of 3,5-o-bls(4-ohlorobenzoyl)-2-
deoxy-a-D-ribosyl chloride (purity: 85 %), and the
mixture was stirred for 10 min to give a solution of a
mixture of the title compounds (18) and (19) [(18) :
(19) = 1:4, a-form/ß-form of compound (18) = 7/10] in 2-
butanone.
To a mixture of 136.8 g of orthophosphorlc acid in 2 L
of 2-butanone were added 90.6 g of tri-n-butylamine
and 200 g of molecular sieves 4A, and the mixture was
cooled to 5 °C with stirring. After stirring for one
hour, to the mixture was added 200 g of 3,5-0-bis(4-
chlorobenzoyl)-2-deoxy-a-D-ribosyl chloride (purity:
85 %), and the mixture was stirred for 2 hours to give a
solution of a mixture of the title compounds (18) and
(19) [(18) : (19) - 5:4, a-form/ß-form of compound (18)
= 5/2] in 2-butanone.
Example 4
Preparation of 3,5-O-bis(4-chlorobenzoyl)-2-deoxy-a-D-
ribose-1-phosphate (18a)
The acetonitrlle solution prepared in Example 1 was
cooled to 5 °C with stirring, and 2.29 g of
orthophosphoric acid was added to the mixture. After
stirring for 3 hours, crystallization was initiated and
then the mixture became a thick suspension. After 5
hours, the ratio of a-form/0-form of the title compound
(18) in the reaction suspension was 10/1. The crystals
were collected as a mixture with molecular sieves. The
solid was dissolved in 100 mL of methanol and the
mixture was again filtrated to remove molecular sieves.
HPLC assay showed that 3.68 g of the title compound
(18a) was contained in the methanol solution (Yield:
74.6 % after reduction from the purity of the starting
material) without the ß-form on HPLC.
Example 5
Preparation of 3,5-O-bls(4-chlorobenzoyl)-2-deoxy-a-D-
robose-1-phosphate (18a)
The 2-butanone solution prepared in Example 2 was
cooled to 5 °C with stirring, and 2.2 g of
orthophosphorlc acid was added to the solution. After
stirring for 1 hour, precipitation of crystals initiated
and then a thick suspension was obtained. After 20
hours, the ratio of a-form/ß-form for compound (18a) in
the reaction suspension was 8:1. To the suspension was
added 6.33 g of tri-n-butylamine to dissolve the
precipitated crystals and molecular sieves were removed
by filtration. To the filtrate was. added 250 mL of
toluene, and the solution was washed with 55 mL of water.
The organic layer was ice-cooled. To the mixture was
added 2.32 g of cyclohexylamine for crystallization with
stirring. After 1 hour, the precipitated crystals were
collected by filtration and dried in vacuo at room
temperature to provide 3.19 g of a dicyclohexylamine
salt of compound (16a) as a colorless powder (Yield:
64.7 % after reduction from the purity of the starting
material; a-form : ß-form = 97.5 : 2.5).
Example 6
Preparation of 3,5-0-bls(4-chlorobenzoyl)-2-deoxy-a-D-
robose-1-phosphate (18a)
The 2-butanone solution prepared in Example 3 was
cooled to 5 °C with stirring. After stirring for 1 hour,
precipitation of crystals initiated and then a thick
suspension was obtained. After 23 hours, the ratio of
a-form/ß-form for compound (18a) in the reaction
suspension was 7:1. To the suspension was added 259 g
of tri-n-butylamine to dissolve the precipitated
crystals and molecular sieves were removed by filtration
The filtrate was washed with 2.2 L of water and the
aqueous layer was extracted with 1 L of toluene. The
combined organic layer was ice-cooled. To the mixture
was added 87.5 g of cyclohexylamine for crystallization
with stirring. After 1 hour, the precipitated crystals
were collected by filtration and dried in vacuo at room
temperature to provide 213 g of a dicyclohexylamine salt
of compound (16a) as a colorless powder (Yield: 78.1 %
after reduction from the purity of the starting
material; a-form : ß-form = 96.9 : 3.1).
Example 7
Preparation of 2-deoxy-a-D-ribose-1-phosphate (20)
To the methanol solution prepared in Example 4 was
added 20 mL of an aqueous solution of ammonium hydroxide
and the mixture was stirred at room temperature. After
stirring for 28 hours, the precipitated crystals were
collected by filtration and dried in vacuo at room
temperature to provide 589 mg of an ammonium salt of
compound (20) as a colorless powder (Yield: 21.1 %
without the ß-form on HPLC).
Example 8
Preparation of 2-deoxy-a-D-ribose-1-phosphate (20)
Compound (18a) prepared in Example 6 was suspended
in a mixture of 2.3 L of methanol and 450 mL of an
aqueous ammonium hydroxide solution, and the mixture was
stirred at room temperature. After stirring for 28
hours, the precipitated crystals were collected by
filtration and dried in vacuo at room temperature to
provide 62.0 g of an ammonium salt of compound (20) as a
colorless powder (Yield: 81.0 % without the ß-form on
HPLC).
To a mixture of 3-. 32 g of orthophosphoric acid in
67 mL of methyl isobutyl ketone were added 2.11 g of
tri-n-butylamine and 6.6 g of molecular sieves 4A, and
the mixture was cooled to 5 °C with stirring. To the
mixture was added 6.66 g of 2,3,5-0-tris(4-
chlorobenzoyl)-a-D-ribosyl chloride. After 1 hour,
precipitation of crystals initiated and then a thick
suspension was provided. After 10 hours, the ratio of
a-form/ß-form for compound (19) in the reaction
suspension was 10:1. To the suspension was added 6.33 g
of tri-n-butylamine to dissolve the precipitated
crystals and molecular sieves were removed by filtration.
The filtrate was washed with 55 mL of water. The
organic layer was ice-cooled. To the mixture was added
2.4 g of cyclohexylamine for crystallization with
stirring. After 1 hour, the precipitated crystals were
collected by filtration and dried in vacuo at room
temperature to provide 7.02 g of a dicyclohexylamine
salt of compound (21) as a colorless powder (Yield:
73.0 %; a-form : ß-form = 99 : 1).
Compound (21) prepared in Example 9 was suspended
in a mixture of 105 mL of methanol and 21 mL of an
aqueous ammonium hydroxide solution, and the mixture was
stirred at room temperature. After stirring for 32
hours, the precipitated crystals were collected by
filtration and dried in vacuo at room temperature to
provide 1.90 g of an ammonium salt of compound (22) as a
colorless powder (Yield: 86.0 % without the ß-form on
HPLC).
To a mixture of 3.5 g of orthophosphoric acid in 33
mL of acetonltrlle were added 2.2 g of tri-n-butylamine
and 3.3 g of molecular sieves 4A, and the mixture was
cooled to 5 °C with stirring. To the mixture was added
3.28 g of 5-0-(4-chlorobenzoyl)-2,3-dideoxy-a-D-ribosyl
chloride. After 1 hour, precipitation of crystals
initiated and then a thick suspension was provided.
After 20 hours, the ratio of a-form/ß-form for compound
(23) in the reaction suspension was 10:1. To the
suspension was added 6.5 g of tri-n-butylamine to
dissolve the precipitated crystals and molecular sieves
were removed by filtration. The filtrate was diluted
with 70 mL of toluene and then washed with 55 mL of
water.. The organic layer was ice-cooled. To the
mixture was added 2.5 g of cyclohexylamine for
crystallization with stirring. After 1 hour, the
precipitated crystals were collected by filtration and
dried in vacuo at room temperature to provide 4.56 g of
a dicyclohexylamine salt of compound (23) as a colorless
powder (Yield: 71.5 %; a-form : ß-form = 97 : 3).
Compound (23) prepared in Example 11 was suspended
in a mixture of 46 mL of methanol and 10 mL of an
aqueous ammonium hydroxide solution, and the mixture was
stirred at room temperature. After stirring for 30
hours, the precipitated crystals were collected by
filtration and dried in vacuo at room temperature to
provide 1.68 g of an ammonium salt of compound (24) as a
colorless powder (Yield: 85.0 % without the ß-form on
HPLC).
To a mixture of 3.3 g of orthophosphoric acid in 67
mL of methyl isobutyl ketone were added 2.1 g of tri-n-
butylamine and 6.6 g of molecular sieves 4A, and the
mixture was cooled to 5 °C with stirring. To the
mixture was added 6.6 g of 2,3,5-0-tris(4-
chlorobenzoyl)-a-D-arabinofuranosyl chloride. After 1
hour, precipitation of crystals initiated and then a
thick suspension was provided. After 8 hours, the ratio
of a-form/ß-form for compound (25) in the reaction
suspension was 10:1. To the suspension was added 6.3 g
of tri-n-butylamine to dissolve the precipitated
crystals and molecular sieves were removed by filtration
The filtrate was washed with 55 mL of water. The
organic layer was ice-cooled. To the mixture was added
2.4 g of cyclohexylamine for crystallization with
stirring. After 1 hour, the precipitated crystals were
collected by filtration and dried in vacuo at room
temperature to provide 6.72 g of a dicyclohexylamine
salt of compound (25) as a colorless powder (Yield:
Compound (25) prepared in Example 13 was suspended
in a mixture of 94 mL of methanol and 18 mL of an
aqueous ammonium hydroxide solution, and the mixture was
stirred at room temperature. After stirring for 48
hours, the precipitated crystals were collected by
filtration and dried in vacuo at room temperature to
provide 1.72 g of an ammonium salt of compound (26) as a
colorless powder (Yield: 82.0 % without the ß-form on
HPLC).
To a solution of 1.06 g of (2R)-2-benzyloxymethyl-
4-(R,S)-acetoxy-l,3-dioxorane in 12 mL of ether under
ice-cooling was added 4 mL of a 4N solution of
hydrochloric acid in dioxane. After stirring 3.5 hours,
the mixture was warmed to room temperature. After
removing the solvent by concentration, the residue was
further subject to azeotropy with toluene to give 500 mg
of (2R)-2-benzyloxymethyl-l,3-dioxoranyl chloride as a
colorless and transparent oil. To 1.1 mL of
acetonitrile were sequentially added 0.27 g of
orthophosphoric acid. 0.66 mL of tri-n-butylamine and
0.23 g of molecular sieves 4A, and the mixture was
stirred for 1.5 hours. To the suspension under ice-
cooling was added 0.27 g of the previous oil, and the
mixture was stirred under ice-cooling for 5.5 hours. To
the mixture was added 0.6 mL of tri-n-butylamine. After
stirring for 30 min, the mixture was diluted with
toluene and extracted with water. The aqueous layer was
extracted with n-butanol and then concentrated. The
concentrate was dissolved in toluene, and to the
solution was added cyclohexylamine to give a
cyclohexylamine salt of compound (27) as a white solid.
In 10 mL of methanol was dissolved 0.2 g of
compound (27) prepared in Example 15. The solution was
subject to hydrogenation under an ambient pressure using
0.11 g of 10 % Pd/C as a catalyst. After removing the
catalyst by filtration*, the filtrate was concentrated to
give a cyclohexylamine of compound (28).
phenylbenzoyl)-a-p-erythropentofuranose-1-phosphate (29)
Seventy rag of molecular sieves 4A was added to a
stirred mixture of 62 mg of orthophosphorlc acid, 52 µL
of tri-n-butylamine and 0.7 mL of acetonitrlle at room
temperature, and the mixture was stirred in an ice-bath.
To the mixture was added 70 mg of 2,3-dideoxy-3-fluoro-
5-0-(4-phenylbenzoyl)-D-erythropentofuranosyl chloride,
and the mixture was reacted at the same temperature for
1 day. Then, to the mixture were added 156 µL of tri-n-
butylamine and then deionized water. The mixture was
extracted with toluene three times. To the organic
layer was added 48 µL of cyclohexylamine and the mixture
was stirred for 30 min. The mixture was concentrated in
vacuo, and acetone was added to form a precipitate,
which was collected by filtration. The residue was
washed with chloroform and dried in vacuo at room
temperature to give a dicyclohexylamine of compound (29)
as a white solid.
To a solution of 21 rag of compound (29) prepared in
Example 17 in 1 mL of methanol was added 20 µL of
cyclohexylamine and the mixture was reacted for 2 weeks.
The mixture was concentrated in vacuo and diethyl ether
was added. The mixture was filtered, and the solid was
dried in vacuo to give 12 rag of a dicyclohexylamine salt
of the title compound as a white solid.
At room temperature 0.86 g of molecular sieves 4A
was added to a stirred mixture of 759 mg of
orthophosphoric acid, 646 µL of tri-n-butylamine and 8.6
mL of acetonltrile at room temperature, and the mixture
was stirred in an ice-bath. To the mixture was added
864 mg of 2,3-dideoxy-3-fluoro-5-O-(4-phenylbenzoyl)-D-
erythropentofuranosyl chloride, and the mixture was
reacted at the same temperature for 1 day. Then, to the
mixture were added 1.94 mL of tri-n-butylamine and then
deionized water. The mixture was extracted with toluene
three times and washed with purified water five times.
The organic layer was separated. To the organic layer
was added 590 µL of cyclohexylamine and the mixture was
stirred for 30 min. The mixture was concentrated in
vacuo. After addition of acetone, the mixture was
stirred and filtrated. The residue was further washed
with isopropyl ether and dried in vacuo at room
temperature to give compound (31) as a white solid, a-
form : ß-form =66 : 34.
To a solution of 0.29 g of compound (31) prepared
in Example 19 in 15 mL of methanol was added 279 [ih of
cyclohexylamine and the mixture was reacted for 1 week.
The mixture was concentrated in vacuo and diethyl ether
was added. After stirring, the mixture was filtered,
and the solid was dried in vacuo to give 185 mg of a
dicyclohexylamine salt of compound (32) as a white solid,
a-form : ß-form =66 : 34.
To 2.84 g of l,3,5-0-trlbenzoy1-2-0-methyl-a-D-
ribose was added 14.5 mL of a 4N solution of
hydrochloric acid in dioxane, and the mixture was
stirred under ice-cooling. After stirring 2.5 hours, 10
mL of a 4N solution of hydrochloric acid in dioxane was
further added, and the mixture stirred for 1 hour.
After evaporating the solvent, the residue was further
subject to azeotropy with 10 mL of dioxane twice to give
3,5-0-dibenzoy1-2-0-methylribosy1-1-chloride.
Separately, 2.98 g of 98 % phosphoric acid was dissolved
in 15 mL of 4-methyl-2-pentanone and after adding 2.8 g
of molecular sieves 4A, the mixture was stirred for 30
min. To the mixture were added 1.42 mL of tri-n-
butylamine and then a solution of the previous 3,5-0-
dibenzoy1-2-O-methylribosy1-1-chloride in 10 mL of 4-
methyl-2-pentanone. After reacting the mixture at room
temperature for 20 hours, it was neutralized with 7.1 mL
of tri-n-butylamine. After removing the molecular
sieves by filtration, the filtrate was washed with 20 ml
of water three times. The organic layer was evaporated
and purified by silica gel column chromatography to give
950 mg of compound (33).
To 850 mg of compound (33) prepared in Example 21
was 20 mL of 14% ammonia-methanol, and the mixture was
reacted at room temperature for 20 hours. After
evaporation of the solvent, diisopropyl ether was added
to form a sludge and the crystalline powder was
collected by filtration. The powder was dissolved in
methanol. To the solution was added cyclohexylamine,
and the mixture was stirred. After evaporating methanol,
diisopropyl ether was added to the residue to form a
sludge. The crystalline powder was collected by
filtration and washed with diisopropyl ether. The
desired product was extracted with water and the aqueous
layer was washed with 4-methyl-2-pentanone twice. The
aqueous layer was concentrated and to the layer was
added diisopropyl ether to form a sludge. After
filtration, the crystals were washed with diisopropyl
ether to give 120 mg of a dicyclohexylamine salt of
To a mixture of 6.92 g of orthophosphoric acid in 80 mL
of acetonitrile were added 5.51 mL of tri-n-
butylamine and 10 g of molecular sieves 4A. The mixture
was stirred at room temperature for 5 hours and allowed
to stand overnight. After cooling to -7 °C, to the
mixture was added 10 g of 3,5-0-bis(4-chlorobenzoyl)-2-
deoxy-a-D-ribosyl chloride (purity: 85 %). The mixture
was stirred for 9 hours and allowed to stand at -15 °C
overnight. After adding 16.5 mL of tri-n-butylamine,
the molecular sieves were removed by filtration. The
filtrate was concentrated and the residue was dissolved
in 4-methyl-2-pentanone and washed with water. The
organic layer was ice-cooled and 5.66 mL of
cyclohexylamine was added with stirring for
crystallization. After 1.5 hours, the precipitated
crystals were filtered and dried in vacuo at room
temperature to give 13.5 g of a dicyclohexylamine salt
of compound (18a). a-form : ß-form = 98.8 : 1.2).
Example 24
Preparation of 2-deoxy-a-D-ribose-1-phosphate (20)
To a solution of 7.05 g of the compound obtained in
Example 23 in methanol was added 2.92 mL of
cyclohexylamine. and the mixture was stirred at room
temperature. After stirring 72 hours, the mixture was
concentrated and to the residue was added ethanol to
provide a suspension which was then stirred. After
collecting the precipitated crystals, they were dried I
vacuo at room temperature to give 3.87 g of a
dicylcohexylamine salt of compound (20) (without the 0-
form on NMR).
Fifty mL of an LB medium was inoculated with
Escherichia coli K-12/X1-10 strain (Stratagene Inc.) and
it was cultured at 37 °C overnight. After collection,
the bacteria was lysed with a lysis solution containing
1 mg/mL of lysozyme. The lysis solution was treated
with phenol and DNA was precipitated as usual by ethanol
precipitation. The DNA precipitate was collected with a
glass rod and washed to prepare an E. coli chromosome
DNA.
Oligonucletldes of SEQ ID Nos. 1 and 2 designed
based on the sequence a known deoD gene in Escherichia
coll (GenBank accession No. AE000508 with a coding
region of base numbers 11531 to 12250) were used as
primers for PCR. These primers have restriction enzyme
recognition sequences for EcoRI and Hind III near 5' -
and 3'-ends, respectively.
SEQ ID No. 1: GTGAATTCAC AAAAAGGATA AAACAATGGC
SEQ ID NO. 2: TCGAAGCTTG CGAAACACAA TTACTCTTT
Using 0.1 mL of a PCR reaction solution containing
6 ng/µL of the above E. coll chromosome DNA completely
digested by restriction enzyme Hind III and the primers
(each at 3µM). PCR was conducted by 30 cycles under the
conditions of denaturation: 96 °C. 1 min; annealing: 55
°C, 1 min; elongation: 74 °C, 1 min per a cycle.
The above reaction product and a plasmid pUC18
(Takara Shuzo Co. Ltd.) were digested by EcoRI and Hind
III and ligated using Ligation-High (Toyobo Co. Ltd.).
The recombinant plasmid obtained was used to transform
Escherichia coli DH5a. The transformed strain was
cultured in an LB agar medium containing 50 µg/mL of
ampicillin and X-Gal (5-bromo-4-chloro-3-indoly1-ß-
galactoslde) to provide an Am-resistant transformant as
a white colony. A plasmld was extracted from the
transformant thus obtained and the plasmld in which a
desired DNA fragment had been inserted was designated as
PUC-PNP73. The transformant thus obtained was
designated as Escherichia coll NT-10905.
Escherichia coli MT-10905 was cultured by shaking
at 37 °C overnight in 100 mL of an LB medium containing
50 µg/mL of Am. The culture medium was centrifuged at
13,000 rpm for 10 min to collect the bacteria. The
bacteria were suspended in 10 mL of 10 mM Tris-
hydrochloride buffer (pH 8.0) and ultrasonlcated to give
a homogenate which was then used as an enzyme source.
Reaction solutions were prepared by adding calcium
chloride (Waco Pure Chemicals, Extra pure grade) at
different concentrations to a mixture of 2.5 mM 2-deoxy-
a-D-ribose-1-phosphate diammonium salt prepared
in Example 8, 2.5 mM adenine (Wako Pure Chemicals, Extra
pure grade), 0.1 mL of the ultrasonic enzyme homogenate
from a purinenucleoside-phosphorylase producing strain
and 10 mM Tris-hydrochloride buffer (pH 7.4). One mL of
a reaction solution was reacted at 30 °C for 24 hours.
At the end of the reaction, a white precipitate had been
formed.
HPLC analysis described below for a post-reaction
solution showed a peak completely identical to the peak
of 2'-deoxyadenosine (Wako Pure Chemicals, Extra pure
grade) in all the post-reaction solutions.
HPLC analysis conditions
Column: YMC-Pack ODS-A312, 150x6.0 mm I.D.
Column temperature: 40 °C
Pump flow rate: 0.75 mL/min
Detection: UV 260 nm
Eluent: 10 mM phosphoric acid : acetonitrile =95 :
5 (V/V)
Table 1 shows the calculation results of a reaction
inversion rate after determining a concentration of 2'-
deoxyadenosine in a post-reaction solution.
A reaction was conducted as described in Example 2 5
except that aluminum chloride was added in place of
calcium chloride. At the end of the reaction, a white
precipitate bad been formed. HPLC analysis for the
post-reaction solutions as described in Example 25
showed a peak completely identical to the peak of 2' -
deoxyadenosine (Wako Pure Chemicals, Extra pure grade)
in all the post-reaction solutions. Table 2 shows the
calculation results of a reaction inversion rate after
determining a concentration of 2'-deoxyadenosine in a
post-reaction solution.
Example 27
Preparation of 2'-deoxyadenosine (3)
A reaction was conducted as described in Example 25
except that 10 mM of barium chloride was added in place
of calcium chloride. At the end of the reaction, a
white precipitate had been formed. HPLC analysis for
the post-reaction solutions as described in Example 25
showed a peak completely identical to the peak of 2'-
deoxyadenosine (Wako Pure Chemicals, Extra pure grade)
in the post-reaction solutions. A reaction inversion
rate after determining a concentration of 2' -
deoxyadenosine in a post-reaction solution was
calculated to be 92.4 %.
Example 28
Preparation of thymidine
One mL of a reaction solution consisting of 2.5 mM
2-deoxy-a-D-ribose-1-phosphate diammonium salt prepared
in Example 8, 2.5 mM thymine (Wako Pure Chemicals, Extra
pure grade), 12 units/mL thymidine phosphorylase (SIGMA),
0 mM or 10 mM calcium nitrate (Wako Pure Chemicals,
Extra pure grade) and 10 mM Tris-hydrochloride buffer
(pH 7.4) was reacted at 30 °C for 24 hours. At the end
of the reaction, a white precipitate had been formed.
HPLC analysis for the post-reaction solutions as
described in Example 25 showed a peak completely
identical to the peak of thymidine (Wako Pure Chemicals,
Extra pure grade) in the post-reaction solution. Table
3 shows the calculation results of a reaction inversion
rate after determining a concentration of thymidine in
the post-reaction solution.
Example 29
Preparation of 2'-deoxyadenosine (4)
One mL of a reaction solution consisting of 100 mM
2-deoxy-a-D-ribose-1-phosphate diammonium salt prepared
in Example 8, 100 mM adenine (Wako Pure Chemicals, Extra
pure grade), 0.1 mL of the ultrasonic enzyme homogenate
from a purinenucleoside-phosphorylase producing strain
prepared in Example 25, 0 to 150 mM calcium chloride
(Waco Pure Chemicals, Extra pure grade) and 100 mM Tris-
hydrochloride buffer (pH 8.0) was reacted at 50 °C for
24 hours. At the end of the reaction, a white
precipitate had been formed. HPLC analysis for the
post-reaction solutions as described in Example 25
showed a peak completely identical to the peak of 2-
deoxyadenosine (Wako Pure Chemicals, Extra pure grade)
in the post-reaction solutions. Table 4 shows the
calculation results of determining a concentration of
2'-deoxyadenosine in a post-reaction solution.
Example 30
Preparation of 2'-deoxyguanosine
One mL of a reaction solution consisting of 100 mM
2-deoxy-a-D-ribose-1-phosphate diammonium salt prepared
in Example 8, 100 mM guanine (Wako Pure Chemicals, Extra
pure grade), 0.1 mL of the ultrasonic enzyme homogenate
from a purinenucleoside-phosphorylase producing strain
prepared in Example 25, 0 mM or 150 mM calcium chloride
(Waco Pure Chemicals, Extra pure grade) and 100 mM Tris-
hydrochloride buffer (pH 8.0) was reacted at 50 °C for
24 hours. At the end of the reaction, a white
precipitate had been formed. HPLC analysis for the
post-reaction solution as described in Example 25 showed
a peak completely identical to the peak of 2-
deoxyguanosine (Wako Pure Chemicals, Extra pure grade)
in the post-reaction solution. Table 5 shows the
calculation results of determining a concentration of
2'-deoxyguanosine in the post-reaction solution.
Example 31
Preparation of adenosine
One mL of a reaction solution consisting of 100 mM
ß-D-ribose-1-phosphate diammonium salt prepared in
Example 10, 100 mM adenine (Wako Pure Chemicals, Extra
pure grade), 0.1 mL of the ultrasonic enzyme homogenate
from a purinenucleoside-phosphorylase producing strain
prepared in Example 25, 0 mM or 150 mM calcium chloride
(Waco Pure Chemicals, Extra pure grade) and 100 mM Tris-
hydrochloride buffer (pH 8.0) was reacted at 50 °C for
24 hours. At the end of the reaction, a white
precipitate had been formed. HPLC analysis for the
post-reaction solution as described in Example 25 showed
a peak completely identical to the peak of adenosine
(Wako Pure Chemicals. Extra pure grade) in the post-
reaction solution. Table 6 shows the calculation
results of determining a concentration of adenosine in
the post-reaction solution.
Example 32
Preparation of 2',3'-dideoxyadenosine
One mL of a reaction solution consisting of 100 mM
2,3-dideoxy-a-D-ribose-1-phosphate diammonium salt
prepared in Example 12, 100 mM adenine (Wako Pure
Chemicals, Extra pure grade), 0.1 mL of the ultrasonic
enzyme homogenate from a purinenucleoside-phosphorylase
producing strain prepared in Example 25, 0 mM or 150 mM
calcium chloride (Waco Pure Chemicals, Extra pure grade)
and 100 mM Tris-hydrochloride buffer (pH 8.0) was
reacted at 50 °C for 24 hours. At the end of the
reaction, a white precipitate had been formed. HPLC
analysis for the post-reaction solution as described
in Example 25 showed a peak completely identical to the
peak of 2',3'-dideoxyadenosine (Sigma, Extra pure grade)
In the post-reaction solution. Table 7 shows the
calculation results of determining a concentration of
2',3'-dideoxyadenosine in the post-reaction solution.
Example 33
Preparation of adenine-9-ß-D-arabinoside
One mL of a reaction solution consisting of 100 mM
a-D-arabinofuranosy1-1-phosphate diammonlum salt
prepared in Example 14, 100 mM adenine (Wako Pure
Chemicals, Extra pure grade), 0.1 mL of the ultrasonic
enzyme homogenate from a purlnenucleoslde-phosphorylase
producing strain prepared in Example 25, 0 mM or 150 mM
calcium chloride (Waco Pure Chemicals, Extra pure grade)
and 100 mM Tris-hydrochloride buffer (pH 8.0) was
reacted at 50 °C for 24 hours. At the end of the
reaction, a white precipitate had been formed. HPLC
analysis for the post-reaction solution as described
in Example 25 showed a peak completely identical to the
peak of adenine-arabinoside (Sigma, Extra pure grade) in
the post-reaction solution. Table 8 shows the
calculation results of determining a concentration of
adenine-9-ß-D-arabinoslde in the post-reaction solution.
Example 34
Preparation of 2-amino-6-chloropurine-2'-deoxy-ß-D-
riboside
One mL of a reaction solution consisting of 10 mM
2-deoxy-a-D-ribose-1-phosphate diammonium salt prepared
in Example 8, 10 mM 2-amino-6-chloropurine (Tokyo Kasei),
100 mM Tris-hydrochloride buffer (pH 7.5) and 50 µL of
the ultrasonic enzyme homogenate from a
purinenucleoside-phosphorylase producing strain prepared
in Example 25 was reacted at 50 °C for 4 hours. At the
end of the reaction, a white precipitate had been formed.
HPLC analysis for the post-reaction solution under the
conditions below showed a peak of 2-amino-6-
chloropurine-2'-deoxy-P-D-riboside. A reaction
inversion rate was calculated to be 20.9 % after
determining the concentration of 2-amino-6-chloropurine-
2'-deoxy-ß-D-rlboside in the post-reaction solution.
HPLC analysis conditions
Column: Develosil ODS-MG-5, 250x4.6 mm I.D.
Column temperature: 40 °C
Pump flow rate: 1.0 mL/min
Detection: UV 254 nm
Eluent: 25 mM potassium dihydrogen phosphate :
methanol « 875 : 125 (V/V)
Example 35
Preparation of 2,6-diaminopurine-2'-deoxy-ß-D-riboside
A reaction was conducted as described in Example 34
except that 2,6-diaminopurine (Tokyo Kasei) was added in
place of 2-amino-6-chloropurine. HPLC analysis for the
post-reaction solution as described in Example 34 showed
a peak of 2,6-dlaminopurine-2'-deoxy-ß-D-riboside. A
reaction inversion rate was calculated to be 75.5 %
after determining the concentration of 2,6-
diaminopurine-2'-deoxy-ß-D-riboside in the post-reaction
solution.
Example 36
Preparation of 6-mercaptopurlne-2'-deoxy-ß-D-riboside
A reaction was conducted as described in Example 34
except that 6-mercaptopurine (KOUJIN) was added in place
of 2-amino-6-chloropurine. HPLC analysis for the post-
reaction solution as described in Example 34 showed a
peak of 6-mercaptopurine-2'-deoxy-0-D-riboside. A
reaction inversion rate was calculated to be 57.2 %
after determining the concentration of 6-mercaptopurine-
2'-deoxy-ß-D-riboside in the post-reaction solution.
Example 37
Preparation of 2-amino-6-lodopurine-2'-deoxy-P-D-
riboside
A reaction was conducted as described in Example 34
except that 2-amino-6-iodopurine was added in place of
2-amino-6-chloropurine. HPLC analysis for the post-
reaction solution as described in Example 34 showed a
peak of 2-araino-6-iodopurine-2'-deoxy-0-D-riboside. A
reaction inversion rate was calculated to be 69.2 %
after determining the concentration of 2-amino-6-
iodopurine-2'-deoxy-ß-D-riboside in the post-reaction
solution.
Example 38
Preparation of 2-acetylamlno-6-hydroxypurlne-2'-deoxy-ß-
D-riboside
A reaction was conducted as described in Example 34
except that 2-acetylamino-6-hydroxypurine (Tokyo Kasei)
was added in place of 2-araino-6-chloropurine. HPLC
analysis for the post-reaction solution under the
conditions described below showed a peak of 2-
acetylamino-6-hydroxypurine-2'-deoxy-ß-D-rlboside. A
reaction inversion rate was calculated to be 48.7 %
after determining the concentration of 2-acetylamino-6-
hydroxypurlne-2'-deoxy-ß-D-riboside in the post-reaction
solution.
HPLC analysis conditions
Column: Develosil ODS-MG-5, 250x4.6 mm I.D.
Column temperature: 40 °C
Pump flow rate: 1.0 mL/min
Detection: UV 254 nm
Eluent: 25 mM potassium dihydrogen phosphate :
methanol «= 75 : 25 (V/V)
Example 39
Preparation of 2-amino-6-cyclopropylaminopurine-2'-
deoxy-ß-D-riboside
A reaction was conducted as described in Example 34
except that 2-amino-6-cyclopropylaminopurine was added
in place of 2-amino-6-chloropurine. HPLC analysis for
the post-reaction solution as described in Example 38
showed a peak of 2-amino-6-cyclopropylaminopurine-2'-
deoxy-p-D-riboside. A reaction inversion rate was
calculated to be 87.6 % after determining the
concentration of 2-amino-6-cyclopropylaminopurine-2'-
deoxy-p-D-riboside in the post-reaction solution.
Example 40
Preparation of 2',3'-dideoxy-3'-fluoro-D-guanosine
One mL of a reaction solution consisting of 7.0 mM
2,3-dideoxy-3-fluoro-D-erythropentofuranose-1-phosphate
prepared in Example 18, 10 mM guanine (Tokyo Kasei), 100
mM Tris-hydrochloride buffer (pH 7.5) and 0.1 mL of the
ultrasonic enzyme homogenate from a purinenucleoside-
phosphorylase producing strain prepared in Example 25
was reacted at 50 °C for 114 hours. HPLC analysis for
the post-reaction solution as described in Example 34
showed a peak of 2',3'-dideoxy-3'-fluoro-D-guanosine. A
reaction inversion rate was calculated to be 47.7 %
after determining the concentration of 2',3'-dideoxy-3'-
fluoro-D-guanosine in the post-reaction solution.
Example 41
Preparation of 2',3'-dideoxy-3'-fluoro-D-guanosine
One mL of a reaction solution consisting of 7.0 mM
2,3-dideoxy-3-fluoro-D-erythropentofuranose-1-phosphate
prepared in Example 18, 10 mM guanine (Tokyo Kasei), 100
mM Tris-hydrochloride buffer (pH 7.5) and 0.1 mL of the
ultrasonic enzyme homogenate from a purinenucleoside-
phosphorylase producing strain prepared in Example 25
was reacted at 50 °C for 47 hours. To the solution was
added calcium chloride to a final concentration of 20 mM
and the mixture was reacted at 50 °C for additional 67
hours. HPLC analysis for the post-reaction solution as
described in Example 34 showed a peak of 2',3'-dideoxy-
3'-fluoro-D-guanosine. A reaction inversion rate was
calculated to be 84.4 % after determining the
concentration of 2',3'-dideoxy-3'-fluoro-D-guanosine in
the post-reaction solution.
Example 42
Preparation of 6-chloro-9-(ß-D-ribofuranos-1-yl)purine
One mL of a reaction solution consisting of 10 mM
6-chloropurine (Aldrlch), 50 mM D-ribose-1-phosphate
(22) prepared in Example 10, 0.1 mL of the ultrasonic
enzyme homogenate from a purlnenucleoslde-phosphorylase
producing strain prepared in Example 25 and 100 mM Tris-
hydrochloride buffer (pH 7.5) was reacted at 50 °C for
20 hours. After completion of the reaction, HPLC
analysis for the reaction solution under the conditions
described below showed a peak of the title compound. A
reaction inversion rate was calculated to be 62.4 %
after determining the concentration of 6-chloro-9-(P-D-
ribofuranos-1-yl)purine in the post-reaction solution.
HPLC analysis conditions
Column: Develosil. ODS-MG-5, 250x4.6 mm I.D.
Column temperature: 40 °C
Pump flow rate: 1.0 mL/min
Detection: UV 254 nm
Eluent: 25 mM potassium dihydrogen phosphate :
methanol = 75 : 25 (V/V)
Example 43
Preparation of 1-(2-deoxy-ß-D-ribofuranos-1-yl)-1H-
imidazo[4,5-b]pyridine and 3-(2-deoxy-ß-D-ribofuranos-1-
yl)-1H-imldazo[4,5-b]pyridine
One mL of a reaction solution consisting of 10 mM
2-deoxy-a-D-ribose-1-phosphate ammonium salt prepared in
Example 8, 10 mM 4-azabenzimidazole (Aldrich), 100 mM
Tris-hydrochloride buffer (pH 7.5) and 50 µL of the
ultrasonic enzyme homogenate from a purinenucleoside-
phosphorylase producing strain prepared in Example 25
was reacted at 50 °C for 17 hours. HPLC analysis for
the post-reaction solution under the conditions
described below showed two peaks of the title compounds.
Reaction inversion rates were calculated to be 3 % and
7.2 % after determining the concentrations of the
products in the post-reaction solution.
Example 44
Preparation of 8-aza-2'-deoxyadenosine
A reaction was conducted as described in Example 43
except that 8-azaadenine (Aldrich) was used in place of
4-azabenzimidazole. HPLC analysis for the post-reaction
solution under the conditions described below showed a
peak of 8-aza-2'-deoxyadenosine. A reaction inversion
rate was calculated to be 4.8 % after determining the
concentration of 8-aza-2'-deoxyadenosine in the post-
reaction solution.
Example 45
Preparation of 8-aza-2'-deoxyguanosine
A reaction was conducted as described in Example 43
except that 8-azaguanine (Tokyo Kasei) was used in place
of 4-azabenzimidazole. HPLC analysis for the post-
reaction solution as described in Example 44 showed a
peak of 8-aza-2'-deoxyguanosine. A reaction inversion
rate was calculated to be 36.1 % after determining the
concentration of 8-aza-2'-deoxyguanosine in the post-
reaction solution.
Example 46
Preparation of 2-chloro-2'-deoxyadenosine (Cladribine)
A reaction was conducted as described in Example 43
except that 2-chloro-4-aminopurine was used in place of
4-azabenziraldazole. HPLC analysis for the post-reaction
solution under the conditions described below showed a
peak of the title compound. A reaction inversion rate
was calculated to be 96 % after determining the
concentration of 2-chloro-2'-deoxyadenosine in the post-
reaction solution.
HPLC analysis conditions
Column: Develosil ODS-MG-5, 250x4.6 mm I.D.
Column temperature: 40 °C
Pump flow rate: 1.0 mL/min
Detection: UV 254 nm
Eluent: 25 mM potassium dihydrogen phosphate :
methanol = 875 : 125 (V/V)
Example 47
Preparation of 1-(ß-D-ribofuranos-1-yl)-1,3,4-triazole-
3-carboxamlde (Ribavirine)
A reaction was conducted as described in Example 43
except that 1,2,4-tosyazole-3-carboxamide was used in
place of 4-azabenzimidazole. HPLC analysis for the
post-reaction solution under the conditions described
below showed a peak of the title compound. A reaction
inversion rate was calculated to be 69 % after
determining the concentration of 1-(ß-D-ribofuranos-1-
yl)-l,3,4-triazole-3-carboxamide in the post-reaction
solution.
HPLC analysis conditions
Column: Develosil ODS-MG-5, 250x4.6 mm I.D.
Column temperature: 40 °C
Pump flow rate: 1.0 mL/mln
Detection: UV 210 nm
Eluent: 25 mM potassium dihydrogen phosphate
Example 48
Preparation of 1-(P-D-ribofuranos-1-yl)-5-
amlnolmlda2ole-4-carboxamlde (Acadesine)
A reaction was conducted as described in Example 43
except that 5-aminoimidazole-4-carboxamide was used in
place of 4-azabenzimidazole. HPLC analysis for the
post-reaction solution under the conditions described
below showed a peak of the title compound. A reaction
inversion rate was calculated to be 46 % after
determining the concentration of 1-(ß-D-ribofuranos-1-
yl)-5-aminoimidazole-4-carboxamide in the post-reaction
solution.
Example 49
Preparation of 2'-deoxyguanosine
To 20 g of purified water were added 3.22 g of 2-
deoxyribose-1-phosphate di(monocyclohexylanunonium) salt
prepared in Example 24 (7.72 mmol), 1.11 g of guanine
(7.34 mmol) and 0.67 g of magnesium hydroxide (11.48
mmol). The reaction mixture was adjusted to pH 9 with a
20 % aqueous solution of sodium hydroxide. To the
mixture was added 0.1 mL of the above enzyme solution
(0.1 mL), and the mixture was reacted with stirring at
50 °C for 8 hours. HPLC analysis for the reaction
mixture after 8 hours indicated that the desired 2'-
deoxyguanosine was provided with a reaction yield of
99 %.
Example 50
Preparation of 2'-deoxyadenosine
To 20 g of purified water were added 3.22 g of 2-
deoxyribose-1-phosphate di(monocyclohexylammonium) salt
prepared in Example 24 (7.72 mmol), 1.01 g of adenine
(7.47 mmol) and 0.67 g of magnesium hydroxide (11.48
mmol). The reaction mixture was adjusted to pH 8.6 with
a 20 % aqueous solution of sodium hydroxide. To the
mixture was added 0.1 mL of the above enzyme solution
(0.1 mL), and the mixture was reacted with stirring at
50 °C for 3 hours. HPLC analysis for the reaction
mixture after 8 hours indicated that the desired 2'-
deoxyadenosine was provided with a reaction yield of
99 %.
Industrial Applicability
As described above, this invention is quite useful
as an anomer selective process for producing a 1-
phosphorylated saccharide derivative or a nucleoside and
may be expected to used in a variety of applications.
WHAT is CLAIMED IS:
1. A process for selectively preparing either a
or ß isomer of a 1-phosphorylated saccharide derivative
monomer comprising the steps of phosphorolyzing and
isomerizing an anomer mixture of a 1-phosphorylated
saccharide derivative to give a and ß isomers of the 1-
phosphorylated saccharide derivative monomer and
selectively crystallizing one of these isomers to
displace the equilibrium between these anomers.
2. A process for selectively preparing either a
or 0 isomer of a 1-phosphorylated saccharide derivative
monomer comprising the steps of phosphorolyzing and
isomerizing an anomer mixture of a 1-phosphorylated
saccharide derivative represented by formula (1):
where R1 and R2 independently represents hydrogen,
methyl, protected hydroxymethyl or protected carboxyl;
R3 represents acyl; R4 represents a protective group for
hydroxy; X represents halogen, alkoxy or alkylthio; W
represents oxygen or sulfur; Z represents oxygen, sulfur
or optionally substituted carbon; m represents an
integer of 1 to 3; n represents 0 or 1; p and q
represents an integer of 0 to 4; and r represents 0 or
1; provided that p, q, r and n meet the conditions of
p+r = n+1 and q = 2x(n+1)-2x(p+r) when Z is oxygen or
sulfur and of p+r = n+2 and q = 2x(n+2) -2x(p+r) when Z
is carbon, to give a and ß isomers of the 1-
phosphorylated saccharide derivative monomer and
selectively crystallizing one of these isomers to
displace the equilibrium between these anomers:
3. A process for preparing a 1-phosphorylated
saccharide derivative monomer represented by formula
(3):
wherein R1 and R2 independently represents hydrogen,
methyl, hydroxymethyl or carboxyl; R3 represents
hydrogen or acyl; and X, W, Z, n, p, q and r are as
defined above, comprising the steps of phosphorolyzing
and isomerizing an anomer mixture of a 1-phosphorylated
saccharide derivative represented by formula (1):
wherein R1. R2, R3, R4, X, W, Z, m, n, p, q and r
are as defined in Claim 2, to give a and ß isomers of
the 1-phosphorylated saccharide derivative monomer;
selectively crystallizing one of these isomers to
displace the equilibrium between these anomers; and then
removing the protective group represented by R4.
4. A trimer, dimer or monomer of a 1-
phosphorylated saccharide derivative represented by
formula (4):
wherein R1 and R2 independently represents hydrogen,
methyl, hydroxymethyl protected with substituted benzoyl
or protected carboxyl; R4 represents hydrogen or a
protective group for hydroxy; and R3, X, w. z, m, n, p.
q and r are as defined in Claim 2, or salts thereof.
5. A 1-phosphorylated saccharide derivative
monomer represented by formula (5):
wherein p and q represents an integer of 0 to 3; r
represents 0 or 1; and R1, R2, R3, R4, X, W and Z are as
defined in Claim 2; provided that p, q and r meet the
conditions of p+q+r = 3 when Z is oxygen or sulfur and
of p+q+r = 5 when Z is carbon, or salts thereof.
6. A 1-phosphorylated saccharide derivative
monomer represented by formula (6):
wherein R1 and R2 independently represents hydrogen.
methyl, hydroxymethyl or carboxy; and R3, X, W. Z, n, p,
q and r are as defined in Claim 2 other than natural
products, or salts thereof.
7. The 1-phosphorylated saccharide derivative
monomer as claimed in Claim 6 wherein n = 1 in formula
(6), or its salt.
8. The 1-phosphorylated saccharide derivative
monomer as claimed in Claim 7 wherein R1 is
hydroxymethyl; R2 is hydrogen; p and r are 0; and 1
is fluorine, or its salt.
9. A process for preparing a 1-phosphorylated
saccharide represented by formula (20):
wherein R11 represents protected hydroxymethyl and
R14 represents a protective group for hydroxy,
comprising the steps of treating a compound represented
by formula (18):
wherein R11 and R14 are as defined above, with
phosphoric acid in the presence of a base to give an
anomer mixture of a 1-phosphorylated saccharide
derivative represented by formula (19):
wherein R11 and R14 are as defined above and m is as
defined in Claim 2; phosphorolyzing and isomerizing the
mixture; and displacing the equilibrium between the
anomer isomers by selectively crystallizing an a-isomer
formed.
10. A process for preparing 2-deoxy-a-D-ribose-1-
phosphate comprising the steps of treating a compound
represented by formula (18):
wherein R11 represents protected hydroxymethyl and
R14 represents a protective group for hydroxy, with
phosphoric acid in the presence of a base to give an
anomer mixture of a 1-phosphorylated saccharide
derivative represented by formula (19):
wherein R11 and R14 are as defined above and m is as
defined in Claim 2; phosphorolyzing and isomerizing the
mixture; displacing the equilibrium between the anomer
isomers by selectively crystallizing an a-isomer formed
to give the a-isomer; and then removing the protective
group.
11. A process for preparing a nucleoside
represented by formula (8):
wherein B is a base independently selected from the
group consisting of pyrimidine, purine, azapurine and
deazapurlne optionally substituted by halogen, alkyl,
haloalkyl, alkenyl, haloalkenyl, alkynyl, amino,
alkylamino, hydroxy, hydroxyamino, aminoxy, alkoxy,
mercapto, alkylmercapto, aryl, aryloxy or cyano; and R1,
R2, R3, X, W, Z, n, p, q and r are as defined for
formula (3) in Claim 3, comprising
the first procedure for preparing the 1-
phosphorylated saccharide derivative monomer as claimed
in Claim 3; and
the second procedure of conducting an exchange
reaction of the phosphate group in the 1-phosphorylated
saccharide derivative obtained in the first procedure
with a base by the action of a nucleoside phosphorylase.
12. A process for preparing a nucleoside
represented by formula (8):
wherein B is as defined for formula (8) in Claim
11; and R1, R2, R3, R4, X, W, Z, n, p, q and r are as
defined for formula (6) in Claim 6, comprising an
exchange reaction of the phosphate group in the 1-
phosphorylated saccharide derivative monomer in as
claimed in Claim 6 with a base by the action of a
nucleoside phosphorylase.
13. A process for preparing a nucleoside
represented by formula (10):
wherein B is as defined for formula (8) in Claim
11; and R1, R2. R3. R4, X, W, Z, n, p, q and r are as
defined for formula (7) in Claim 7, comprising an
exchange reaction of the phosphate group in the 1-
phosphorylated saccharide derivative monomer as claimed
in Claim 7 with a base by the action of a nucleoside
phosphorylase.
14. The process for preparing a nucleoside as
claimed in Claim 13 wherein R1 is hydroxymethyl, R2 is
hydrogen, p and r are 0, and X is fluorine.
15. A process for preparing a nucleoside
represented by formula (21):
wherein B is as defined for formula (8) in Claim 11,
comprising
the first procedure of preparing 2-deoxy-a-D-
ribose-1-phosphate as claimed in Claim 14; and
the second procedure of conducting an exchange
reaction of the phosphate group in the 1-phosphorylated
saccharide derivative obtained in the first procedure
with a base by the action of a nucleoside phosphorylase.
16. The process for preparing a nucleoside as
claimed in any of Claims 11 to 15 wherein the nucleoside
phosphorylase is at least one enzyme selected from the
group consisting of purine nucleoside phosphorylase
(EC2.4.2.1), guanosine nucleoside phosphorylase
(EC2.4.2.15). pyrimidine nucleoside phosphorylase
(EC2.4.2.2), uridine nucleoside phosphorylase
(EC2.4.2.3), thymidine nucleoside phosphorylase
(EC2.4.2.4) and deoxyuridine nucleoside phosphorylase
(EC2.4.2.23).
17. The process for preparing a nucleoside as
claimed in any of Claims 11 to 15 wherein the nucleoside
phosphorylase activity is replaced with a microorganism
expressing at least one nucleoside phosphorylase
selected from the group consisting of purine nucleoside
phosphorylase (EC2.4.2.1), guanosine nucleoside
phosphorylase (EC2.4.2.15), pyrimidine nucleoside
phosphorylase (EC2.4.2.2), uridine nucleoside
phosphorylase (EC2.4.2.3), thymidine nucleoside
phosphorylase (EC2.4.2.4) and deoxyuridine nucleoside
phosphorylase (EC2.4.2.23).
18. The process for preparing a nucleoside as
claimed in any of Claims 11 to 15 wherein a metal cation
capable of forming a water-insoluble salt with a
phosphate ion is present in the reaction solution during
the exchange reaction of a phosphate group in the 1-
phosphorylated saccharide derivative monomer with a base
by the action of a nucleoside phosphorylase.
19. The process for preparing a nucleoside as
claimed in Claim 18 wherein the metal cation capable of
forming a water-insoluble salt with the phosphate ion is
at least one metal cation selected from the group
consisting of calcium, barium, aluminum and magnesium
ions.
20. The process for preparing a nucleoside as
claimed in Claim 8 wherein the nucleoside is a natural
nucleoside.
21. A synthetic nucleoside represented by formula
(11):
wherein B, R1, R2, R3, R4, X, W, z, n, p. q and r
are as defined for formulas (8) in Claim 11 or its salt,
excluding trifluorothymidine, ribavirin, orotidine.
uracil arabinoside, adenine arabinoside, 2-methyl-
adenine arabinoside, 2-chloro-hypoxanthine arabinoside,
thioguanine arabinoside, 2,6-diaminopurine arabinoside,
cytosine arabinoside, guanine arabinoside, thymine
arabinoside, enocitabine, gemcitabine, azidothymidine,
idoxuridine, dideoxyadenosine, dideoxyinosine,
dideoxycytidine, didehydrodeoxythymidine,
thiadideoxycytidine, sorivudine, 5-methyluridine,
virazole, thioinosine, tegafur, doxifluridine, bredinin,
nebularine, allopurinol uracil, 5-fluorouracil, 2'-
aminouridine, 2'-aniinoadenosine, 2'-aminoguanidine, 2-
chloro-2'-aminoinosine, DMDC and FMDC.
22. A synthetic nucleoside represented by formula
(12):
wherein B, R1, R2, R3, R4, X, W, Z, n, p, q and r
are as defined for formulas (8) in Claim 11 or its salt,
excluding trifluorothymidine, ribavirin, orotidine,
uracil arabinoside, adenine arabinoside, 2-methyl-
adenine arabinoside, 2-chloro-hypoxanthine arabinoside,
thioguanine arabinoside, 2,6-diaminopurine arabinoside,
cytosine arabinoside, guanine arabinoside, thymine
arabinoside, enocitabine, gemcitabine, azidothymidine,
idoxuridine, dideoxyadenosine, dideoxyinosine,
dideoxycytidine, didehydrodeoxythymidine,
thiadideoxycytidine, sorivudine, 5-methyluridine,
virazole, thioinosine, tegafur, doxifluridine, bredinin,
nebularine, allopurinol uracil, 5-fluorouracil, 2'-
aminouridine, 2'-aminoadenosine, 2'-aminoguanidine, 2-
chloro-2'-aminoinosine, DMDC and FMDC.
23. A nucleoside represented by formula (13):
wherein B, R1. R2. R3, R4, X, W, Z, n, p. q and r
are as defined for formulas (8) in Claim 11 or its salt,
excluding trifluorothymidine, ribavirin, orotidine,
uracil arabinoside, adenine arabinoside, 2-methyl-
adenine arabinoside, 2-chloro-hypoxanthine arabinoside,
thioguanine arabinoside, 2,6-diaminopurine arabinoside,
cytosine arabinoside, guanine arabinoside, thymine
arabinoside, enocitabine, gemcitabine, azidothymidine,
idoxuridine, dideoxyadenosine, dideoxyinosine,
dideoxycytidine, didehydrodeoxythymidine,
thiadideoxycytidine, sorivudine, 5-methyluridine,
virazole, thioinosine, tegafur, doxifluridine, bredinin,
nebularine, allopurinol uracil, 5-fluorouracil. 2'-
aminouridine, 2'-aminoadenosine, 2'-aminoguanidine, 2-
chloro-2'-aminoinosine, DMDC and FMDC.
24. A 1-phosphorylated saccharide represented by
formula (20):
wherein R11 represents protected hydroxymethyl; and
R14 represents a protective group for hydroxy, or its
salt.

A desired isomer is selectively prepared by
phosphorolyzing and isomerizing an anomer mixture of a
1-phosphorylated saccharide derivative while
crystallizing one of the isomers to displace the
equilibrium. Furthermore, using the action of a
nucleoside phosphorylase, a nucleoside is prepared from
the 1-phosphorylated saccharide derivative obtained and
a base with improved stereoselectivity and a higher
yield. This process is an anomer-selective process for
preparing a 1-phosphorylated saccharide derivative and a
nucleoside.