U.S. patent application number 13/675220 was filed with the patent office on 2016-11-17 for novel process for the recovery of beta acetylfuranoside.
This patent application is currently assigned to Hoffmann-La Roche Inc.. The applicant listed for this patent is HOFFMANN-LA ROCHE INC.. Invention is credited to Martin Behringer, Bernd Junghans, Bernhard Knipp, Bernhard Pfeil, Gerald Zieres.
Application Number | 20160333040 13/675220 |
Document ID | / |
Family ID | 40801987 |
Filed Date | 2016-11-17 |
United States Patent
Application |
20160333040 |
Kind Code |
A9 |
Behringer; Martin ; et
al. |
November 17, 2016 |
Novel Process for the Recovery of Beta Acetylfuranoside
Abstract
There is provided an improved method for the recovery of
residual, unseparated .beta.-ACF from reaction mixtures remaining
from an initial synthesis of ACF, which is in particular usable on
a large industrial scale, more particularly in the production of
capecitabine.
Inventors: |
Behringer; Martin;
(Bobenheim-Roxheim, DE) ; Junghans; Bernd;
(Edingen-Neckarhausen, DE) ; Knipp; Bernhard;
(Kuerten-Oipe, DE) ; Pfeil; Bernhard;
(Ludwigshafen, DE) ; Zieres; Gerald; (Worms,
DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
HOFFMANN-LA ROCHE INC. |
Nutley |
NJ |
US |
|
|
Assignee: |
Hoffmann-La Roche Inc.
Nutley
NJ
|
Prior
Publication: |
|
Document Identifier |
Publication Date |
|
US 20130072674 A1 |
March 21, 2013 |
|
|
Family ID: |
40801987 |
Appl. No.: |
13/675220 |
Filed: |
November 13, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
12690167 |
Jan 20, 2010 |
|
|
|
13675220 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C07H 13/04 20130101;
C07H 1/00 20130101 |
International
Class: |
C07H 13/02 20060101
C07H013/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 27, 2009 |
EP |
09151384.6 |
Claims
1. A method for recovery of initially not separated .beta.-ACF from
mother liquor remaining from the synthesis of ACF, wherein the
.beta.-ACF is recovered by a combination of at least one
distillation method and at least one chemical reaction step.
2. The method according to claim 1 comprising the following
sequential steps: a) Evaporation to less than 1% residual solvent
of the mother liquor remaining from an initial synthesis of ACF, to
increase the content of residual .alpha./.beta.-ACF from about 8 to
15 weight-% to about 25 to 45 weight-%, followed by distillation to
about 60 to 80 weight-% and subsequent crystallization of
.beta.-ACF out of the distillate by adding a suitable solvent; b)
Chemical conversion of .alpha./.beta.-ACF mixture remaining in the
mother liquor of step a), to .beta.-ACF by de-acetylation and
subsequent re-acetylation, followed by crystallization of
.beta.-ACF by addition of a suitable solvent; c) Optional
repetition of step a) and b) in a sequential (clockwise) cyclic
process.
3. The process according to claim 2, wherein the distillation to
about 60 to 80 weight-% of step a) is carried out at 1 to 3 mbar
and 200 to 210.degree. C. heating temperature in a continuous
thin-film evaporator.
4. The process according to claim 3, wherein step b) comprises the
de-acetylation of .alpha./.beta.-ACF in the presence of a suitable
base, followed by neutralization with a suitable acid and further
followed by the re-acetylation reaction in the presence of suitable
base, a suitable catalyst and a suitable acetylating agent.
Description
PRIORITY TO RELATED APPLICATION(S)
[0001] This application is a continuation of U.S. application Ser.
No. 12/690,167, filed Jan. 20, 2010, now Pending, which claims the
benefit of European Patent Application No. 09151384.6, filed Jan.
27, 2009, which is hereby incorporated by reference in its
entirety.
[0002] The present invention is directed to a novel process for the
recovery of further .beta.-Acetylfuranoside (.beta.-ACF,
.beta.-5-deoxy-1,2,3-tri-O-acetyl-D-ribofuranose) from mother
liquors and process waste streams remaining from an initial
synthesis of ACF.
BACKGROUND OF THE INVENTION
[0003] ACF can be prepared according to well known methods, as for
example described in Helvetica Chimica Acta, Vol. 65 (Nr. 149),
Fasc. 5, 1982, 1531. The synthesis of ACF leads to a racemic
mixture of .alpha.- and .beta.-ACF which can be separated by
selective crystallization and thus precipitation from the reaction
mixture. Usually the .beta.-ACF is the desired product, as it is a
valuable starting material used in the manufacture of inter alia
cytidine derivatives, such as capecitabine. Capecitabine is the
active ingredient of the medicament Xeloda.TM.. The ACF synthesis
can be summarized according to the following reaction scheme 1:
##STR00001##
[0004] EP 0 021 231 as well as WO 2005/040184 disclose the further
reaction of the unseparated ACF racemic mixture, containing both
.alpha.- and .beta.-ACF, to a final product. The separation is thus
only carried out subsequent to the reaction of the .beta.-anomer to
the desired end product.
[0005] In any of the known methods the remaining, residual reaction
mixture (mother liquor) contains about 8-15 weight-% of not
precipitated .alpha./.beta.-Acetylfuranoside (ratio .alpha.:.beta.
is about 35:65), which is not separated from the reaction mixture.
Consequently, and in particular when used on an industrial scale,
considerable amounts of valuable .beta.-ACF are wasted, huge
amounts of waste residue have to be worked-up and the costs for the
entire manufacturing process up to the final product rise
significantly.
[0006] It is therefore the objective of the present invention to
provide an improved method for the recovery of residual,
unseparated .beta.-ACF from reaction mixtures remaining from an
initial synthesis of ACF, which is in particular usable on a large
industrial scale, more particularly in the production of
5'-deoxy-5-fluoro-N-(pentyloxycarbonyl) cytidine (capecitabine).
The advantages of the method according to the present invention are
the increase of the overall yield of .beta.-ACF, and consequently
also of capecitabine per production cycle, thereby reducing the
overall production costs. In addition, the present method renders
the entire manufacturing more environmentally friendly due to
avoiding of unnecessary high amounts of chemical waste. The method
according to the present invention can also optionally be repeated
in several serially connected cycles, thereby further improving the
efficacy of the present method.
SUMMARY OF THE INVENTION
[0007] In one embodiment, the present invention provides a method
for recovery of initially not separated .beta.-ACF from mother
liquor remaining from the synthesis of ACF, wherein the .beta.-ACF
is recovered by a combination of at least one distillation method
and at least one chemical reaction step.
[0008] In a preferred embodiment the method according to the
present invention comprises the following sequential reaction
steps: [0009] a) Evaporation to less than 1% residual solvent of
the mother liquor remaining from an initial synthesis of ACF, to
increase the content of residual .alpha./.beta.-ACF from about 8 to
15 weight-% to about 25 to 45 weight-%, followed by distillation to
about 60 to 80 weight-% and subsequent crystallization of
.beta.-ACF out of the distillate by adding a suitable solvent;
[0010] b) Chemical conversion of .alpha./.beta.-ACF mixture
remaining in the mother liquor of step a), to .beta.-ACF by
de-acetylation and subsequent re-acetylation, followed by
crystallization of .beta.-ACF by addition of a suitable solvent;
[0011] c) Optional repetition of step a) and b) in a sequential
(clockwise) cyclic process.
[0012] In still another preferred embodiment according to the
present invention, the distillation to about 60 to 80 weight-% in
process step a) as described above is carried out at 1 to 3 mbar
and 200 to 210.degree. C. heating temperature in a continuous
thin-film evaporator. The mixture which has to be distilled does
surprisingly not decompose under these conditions though normally
.beta.-Acetylfuranoside begins to decompose at 150.degree. C.
[0013] In yet another preferred embodiment there is provided the
method as described above, wherein step b) comprises the
de-acetylation of .alpha./.beta.-ACF in the presence of a suitable
base, followed by neutralization with a suitable acid and further
followed by the re-acetylation reaction in the presence of suitable
base, a suitable catalyst and a suitable acetylating agent.
[0014] In a particularly preferred embodiment according to the
present invention, the process step a) as described above is
carried out according to the specific conditions as described in
the accompanying Example 1; and the process step b) is carried out
according to the specific conditions as described in the
accompanying Example 2.
[0015] In another particularly preferred embodiment there is
provided the process for recovery of .beta.-ACF according to the
present invention used during the manufacture of capecitabine.
DETAILED DESCRIPTION OF THE INVENTION
Definitions
[0016] The term "mother liquor" means any remaining mixture of
residual starting materials or by-products left over after a main
reaction product is isolated from that mixture in any step
according to the present method. In particular, as used herein the
term mother liquor means the remaining mixture subsequent to the
synthesis of ACF according to scheme 1 above, which contains
residual amounts of .alpha./.beta.-ACF together with a variety of
impurities and by-products.
[0017] The term "distillation" or "distillation method" as used
herein preferably means falling-film evaporator, molecular
distillation, centrifugal molecular distillation, continuous simple
distillation or related apparatus. A particularly preferred
distillation method according to the present invention is the use
of a thin-film evaporator.
[0018] The term "suitable solvent" in connection with the
crystallization of .beta.-ACF preferably means aliphatic alcohols,
most preferably propan-2-ol.
[0019] The term "chemical reaction step" or "chemical conversion"
as used herein means the conversion of the mixture of .alpha.- and
.beta.-Acetylfuranoside (.alpha./.beta.-ACF), which are both
present in a ratio .alpha.:.beta. of about 1:1, towards an
increased amount of .beta.-Acetylfuranoside by a series of chemical
reaction steps, in particular by de-acetylation and subsequent
re-acetylation.
[0020] The term "suitable base" in connection with the
de-acetylation in step b) as described herein means alkali
hydroxides or alkali alcoholates, preferably sodium methanolate
(sodium methoxide).
[0021] The term "suitable acid" in connection with step b) as
described herein means any conventional acid, preferably
hydrochloric acid.
[0022] The term "suitable base" in connection with the
re-acetylation in step b) as described herein means a base,
preferably aliphatic or aromatic amines, most preferably
triethylamine, n-methylpiperidine or pyridine.
[0023] The term "suitable acetylation agent" in connection with
re-acetylation in step b) as described herein means acetic
anhydride or acetyl halides, e. g. acetyl chloride.
[0024] The term "suitable catalyst" in connection with the
re-acetylation in step b) as described herein means substituted
amino-pyridines, preferably 4-dimethylaminopyridine.
[0025] The de-acetylation mentioned under step b) above is
preferably carried out in aliphatic alcohols, in particular
methanol, as solvents and at temperatures between 0 and -20.degree.
C., preferably -5 and -10.degree. C. Subsequently, the reaction
mixture is neutralized with a mineral acid, preferably hydrochloric
acid, up to pH 4-6, preferably 5. The initial solvent, thus the
aliphatic alcohol, is removed by distillation and replaced by a new
solvent selected from chlorinated hydrocarbons, preferably
methylenchloride or aromatic hydrocarbons, preferably toluene.
Subsequently re-acetylation is carried out by the addition of a
suitable amine, preferably triethylamine, 4-dimethylaminopyridine
and acetic anhydride at temperatures of below 30.degree. C.,
preferably 15.degree. C. to 20.degree. C.
[0026] Further details of the conditions for both steps a) and b)
as described herein, together with appropriate work-up procedures,
are given below and in particular by the accompanying working
examples. The sequential use of steps a) and b), optionally
followed by c), according to the specific parameters, temperature
ranges, substances, solvents and conditions used in the disclosed
working examples 1 and 2, respectively form a further particularly
preferred embodiment according to the present invention.
[0027] The optional repetition of the sequential recovery cycle
according to the present invention as mentioned under step c)
above, can be carried out as many times as necessary. Possible
limitations in the number of recovery cycles may arise from
technical and chemical considerations, for example if no further
.beta.-ACF can be recovered or if the amount of recovered
.beta.-ACF becomes to small to justify the costs of the further
continuation of the recovery cycle.
[0028] The essential process steps according to the present
invention can be generally carried out as follows:
Distillative Recovery of .beta.-Acetylfuranoside
[0029] Mother liquors and waste streams remaining from the chemical
standard procedure to obtain .beta.-ACF according to scheme 1
above, contain considerable amounts of
.alpha./.beta.-Acetylfuranoside besides a variety of impurities and
by-products.
[0030] After the mother liquor/waste stream solvent is removed
("Desolventizing") under reduced pressure (0 to 1000 mbar,
preferably 0 to 200 mbar) and at 10 to 100.degree. C., preferably
30 to 80.degree. C., the obtained evaporation residue is feeded to
a continuous or semi-continuous distillation as thin-film
evaporator, falling-film evaporator, molecular distillation,
centrifugal molecular distillation, continuous simple distillation
or related apparatus. The use of a thin-film evaporator or
molecular distillation is especially preferred.
[0031] The residue is than distilled under reduced pressure at 0 to
10 mbar, preferably 0 to 5 mbar, and 100-210.degree. C. heating
temperature (preferably 180-210.degree. C.). The distillate can be
used and processed as crude oil or is dissolved and crystallized
from organic solvent (preferably propan-2-o1).
Chemical Conversion of ACF Mother Liquor
[0032] The conversion of .alpha./.beta.-Acetylfuranoside to
.beta.-Acetylfuranoside can be carried out according to the process
of scheme 2 below:
##STR00002##
[0033] In a first step, solvent from the initial ACF synthesis
(scheme 1) is distilled off. The following deacetylation is carried
out with a suitable solvent such as aliphatic alcohols, preferably
methanol and a suitable base such as alkali hydroxides or alkali
alcoholates, preferably sodium methoxide, at reaction temperatures
of 0.degree. C. to -20.degree. C., preferably at -5.degree. C. to
-10.degree. C.
[0034] The reaction mixture is neutralized with an acid, preferably
hydrochloric acid, up to pH 4-6, preferably 5. The alcohol is
distilled off and the residue treated with a suitable solvent such
as chlorinated hydrocarbons, preferably methylenchloride or
aromatic hydrocarbons, preferably toluene.
[0035] After addition of an amine, preferably triethylamine, acetic
anhydride is added slowly at batch temperatures of below 30.degree.
C., preferably 15.degree. C. to 20.degree. C.
4-dimethylaminopyridine and additionally acetic anhydride are
added. The batch is quenched with water and a suitable solvent such
as chlorinated hydrocarbons, preferably methylenchloride or
aromatic hydrocarbons, preferably toluene is added.
[0036] The organic layer is separated and the aqueous layer several
times extracted with the suitable solvent mentioned above. The
combined organic layers are washed with an alkali solution,
preferably sodium bicarbonate, leading to pH 8 after washing and
further washed with water. The solvent is distilled off and
.beta.-ACF crystallized in suitable solvents such as aliphatic
alcohols, preferably propan-2-ol. The crude product is
recrystallized in a suitable solvent such as aliphatic alcohols,
preferably propan-2-ol, resulting in white .beta.-Acetylfuranoside
crystals with a content of <2 weight-% of the .alpha.-anomer.
The method described herein is also referred to as "Chemical
Reprocessing" in FIG. 1 which further summarizes the present
process.
BRIEF DESCRIPTION OF THE DRAWINGS
[0037] FIG. 1: Process flow chart summarizing the process according
to the present invention
EXAMPLES
[0038] The invention is now further illustrated by the followings
working examples, which are by no means intended to limit the scope
of the present method.
Example 1
Distillative Recovery of .beta.-Acetylfuranoside
Distillation
[0039] 3000 kg Acetylfuranoside mother liquor (ratio .alpha./.beta.
35:65) was evaporated to an oil (residual solvent <1%) at 30 to
80.degree. C. and 5 to 100 mbar (about 1000 kg residual oil). The
residual oil was distilled under vacuum at 1 to 3 mbar and 200 to
210.degree. C. steam heating temperature in a continuous thin-film
evaporator resulting in 609 kg distillate (containing
.alpha./.beta.-Acetylfuranoside) and about 400 kg residue.
Crystallization
[0040] 1247 kg distillate (ratio .alpha./.beta. 35:65) was
dissolved in 541 L propan-2-ol at 20 to 25.degree. C. and cooled to
-12 to -8.degree. C. The resulting suspension was agitated for 6
hours to complete crystallization. The crystallizate was isolated
and washed with cold propan-2-ol. 425 kg of white crude product was
obtained (2-3% residual moisture).
[0041] 755 kg of crude product was recrystallized from propan-2-ol
(ratio 1:1) under the same conditions. Yield: 748 kg
.beta.-Acetylfuranoside.
Example 2
Chemical Conversion of .alpha./.beta.-Acetylfuranoside
[0042] 811 kg Acetylfuranoside mother liquor (about 250 kg
.alpha./.beta.-Acetylfuranoside) was concentrated by distillation
to obtain an oily residue (ratio .alpha./.beta.60:40). Then 1060 L
of methanol was added and cooled to -8.degree. C. 127 L of sodium
methoxide was then added and stirred for 3 hours. The reaction
mixture was neutralized with 126 L of semi concentrated
hydrochloric acid to bring the pH to 5.1.
[0043] 1235 L of solvents were distilled off 212 L of toluene; 322
L of triethylamine and 42 L of toluene were added. 265 L of acetic
anhydride were added slowly, keeping the batch temperature between
15-17.degree. C. The mixture was stirred at 16-17.degree. C. for
1.5 hours. 6.06 kg of 4-dimethylaminopyridine and additionally 367
L of acetic anhydride were added. The batch was stirred for 1.5
hours. The reaction mixture was quenched with 212 L of water and
265 L of toluene were added. After the aqueous layer was separated,
it was extracted 3 times with 265 L of toluene. The combined
organic layers were washed twice with 550 L of saturated sodium
bicarbonate solution, leading to pH 8 after washing, and 530 L of
water. Toluene was then distilled off and 424 L of propan-2-ol were
added and the residue dissolved. The solution was cooled to
-9.degree. C. for 6 hours. The crystallizate was isolated and
washed with cold propan-2-ol. 205.2 kg of white product were
obtained (2-3% residual moisture). Finally, the crude product was
recrystallized with 205 L of propan-2-ol. Yield: 187.8 kg
.beta.-Acetylfuranoside.
* * * * *