U.S. patent application number 10/821986 was filed with the patent office on 2005-06-02 for process for preparing cephalosporins with salified intermediate.
This patent application is currently assigned to ACS DOBFAR S.p.A.. Invention is credited to Manca, Antonio, Marsili, Leonardo, Monguzzi, Riccardo, Zenoni, Maurizio.
Application Number | 20050119244 10/821986 |
Document ID | / |
Family ID | 34621688 |
Filed Date | 2005-06-02 |
United States Patent
Application |
20050119244 |
Kind Code |
A1 |
Monguzzi, Riccardo ; et
al. |
June 2, 2005 |
Process for preparing cephalosporins with salified intermediate
Abstract
Cephalosporins may be conveniently prepared by a process in
which 7-ACA is silylated, acylated, desilylated and then salified
to give an intermediate which is eventually cyclized with
thiourea.
Inventors: |
Monguzzi, Riccardo; (Dorio
(LC), IT) ; Manca, Antonio; (Milano, IT) ;
Marsili, Leonardo; (Brescia, IT) ; Zenoni,
Maurizio; (Paullo (MI), IT) |
Correspondence
Address: |
OBLON, SPIVAK, MCCLELLAND, MAIER & NEUSTADT, P.C.
1940 DUKE STREET
ALEXANDRIA
VA
22314
US
|
Assignee: |
ACS DOBFAR S.p.A.
TRIBIANO (MI)
IT
|
Family ID: |
34621688 |
Appl. No.: |
10/821986 |
Filed: |
April 12, 2004 |
Current U.S.
Class: |
514/202 ;
540/222 |
Current CPC
Class: |
C07D 501/00
20130101 |
Class at
Publication: |
514/202 ;
540/222 |
International
Class: |
A61K 031/545; C07D
501/14 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 2, 2003 |
IT |
MI2003A 002354 |
Feb 12, 2004 |
IT |
MI2004A 000233 |
Claims
1. A process for preparing a cephalosporin of formula (I) 20in
which R.sup.1 is H or Na and R.sup.2 is chosen from the group
consisting of H, CH.sub.3, CH.sub.2OCH.sub.3, CH.sub.2OCOCH.sub.3,
CH.dbd.CH.sub.2, 21according to which a compound of formula (II)
22in which R.sup.2 has the aforestated meanings is silylated at the
carboxyl to give the corresponding trialkylsilyl-ester which is
reacted with a compound of formula (III) 23in which X is Cl or Br
and Y is Cl, or O--CH.dbd.N.sup.+(CH.sub.3).sub.2 Cl.sup.-to give a
cephalosporin of formula (IV) 24in which X and R.sup.2 have the
aforestated meanings, and R.sup.3 is trialkylsilyl, which is
hydrolyzed at pH 7.div.7.5 and then treated in a partly aqueous
solution with benzathine or a salt thereof, to obtain
crystallization of a new cephalosporin of formula (V) 25where Z is
benzathine, in which the carboxyl is salified by the benzathine,
this salt being filtered off, washed with water and reacted in a
partly aqueous solvent with thiourea, to lead to the formation of
the 2-(2-aminothiazol-4-yl)-2-methoxyiminoacetic chain and give a
solution of the compound of general formula (I) in which R.sup.2
has the aforestated meanings and R.sup.1 is H, the compound of
formula (I) being crystallized from this solution in the form of
the sodium salt, of the salt of a pharmaceutically acceptable
inorganic acid or of an internal salt.
2. A process according to claim 1, wherein simultaneously with the
formation of the 2-(2-aminothiazol-4-yl)-2-methoxyyminoacetic
chain, there is the precipitation of benzathine hydrochloride which
is filtered off and removed to leave a very pure solution of the
compound of general formula (I).
3. A process as claimed in claim 1, wherein a product of formula
(I) is obtained in which R.sup.1 is H or Na and R.sup.2 is chosen
from the group consisting of H, CH.sub.3, CH.sub.2OCH.sub.3,
CH.sub.2OCOCH.sub.3, CH.dbd.CH.sub.2 26
4. A process as claimed in claim 2, wherein a product of formula
(I) is obtained in which R.sup.1 is H or Na and R.sup.2 is chosen
from the group consisting of H, CH.sub.3, CH.sub.2OCH.sub.3,
CH.sub.2OCOCH.sub.3, CH.dbd.CH.sub.2 27
5. The benzathine salt of a cephalosporin of formula (V) 28where Z,
X and R are as specified in claim 1.
6. A process for preparing the benzathine salt of a cephalosporin
of formula (V) of claim 5, according to which a compound of formula
(II) 29in which R.sup.2 has the aforestated meanings, is silylated
at the carboxyl to give the corresponding trialkylsilyl-ester which
is reacted with a compound of formula (III) 30in which X is Cl or
Br and Y is Cl, or O--CH.dbd.N.sup.+(CH.sub.3).sub.2 Cl.sup.-to
give a cephalosporin of formula (IV) 31in which X and R.sup.2 are
as specified in claim 1, and R.sup.3 is trialkylsilyl, which is
hydrolyzed at pH 7.div.7.5 and then treated in a partly aqueous
solution with benzathine or a salt thereof, thus obtaining
crystallization of a cephalosporin of formula (V) in which the
carboxyl is salified by the benzathine, this salt being filtered
off and washed with water.
Description
FIELD OF THE INVENTION
[0001] Numerous cephalosporins of formula (I) 1
[0002] characterised by the
2-(2-aminothiazol-4-yl)-2-methoxyiminoacetic chain in position 2 of
the 7-ACA, and its derivatives of formula (II) 2
[0003] are known in which R.sup.2 can have various meanings
including CH.sub.2OCOCH.sub.3 in the case of 7-ACA, the cefotaxime
nucleus or 3
[0004] in the case of 7-ACT, the ceftriaxone nucleus, or 4
[0005] in the case of Furaca, the ceftiofur nucleus.
BACKGROUND OF THE INVENTION
[0006] Each of these cephalosporins, including those having a
different meaning of R.sup.1 and R.sup.2, has been invented and
synthesized with its own synthesis method, so that initially there
was no common method suitable for producing all cephalosporins
having the 2-(2-aminothiazol-4-yl)-2-methoxyiminoacetic chain.
DESCRIPTION OF THE RELATED ART
[0007] Recently, in 1996, U.S. Pat. No. 5,583,216 was granted (the
filing date of which however was many years previously),
generically covering any process usable for inserting the aforesaid
chain into 7-ACA and its derivatives. In this manner, any
cephalosporin included in the aforesaid group falls within the
scope of protection of U.S. Pat. No. 5,583,216 for what concerns
the methods used up to the present time for its production, even if
that cephalosporin was invented many years prior to the granting of
U.S. Pat. No. 5,583,216: however in truth, this patent does not
describe any process which can be applied industrially for
producing cephalosporins.
[0008] To avoid U.S. Pat. No. 5,583,216, considerable research has
been carried out, leading inter alia to the granting of U.S. Pat.
No. 6,458,949 which claims the intermediate of formula (A) 5
[0009] in which X is Cl or Br, usable for preparing ceftiofur by
cyclization with thiourea.
[0010] This intermediate is always precipitated in acid form from a
solution in methylene chloride at 2-5.degree. C., filtered off,
washed with cold water (5.degree. C.) and then with methylene
chloride. In fact, considering that the precipitate originates from
a solution in methylene chloride, according to the usual technique
it would have been logical to expect the first wash to have been
effected with the same solvent, the water wash being effected only
later. This reversal of the wash order and the use of cold water is
therefore not random, but points to the fact that the intermediate
does not possess great stability and that the water-soluble acid
impurities which impregnate the solid just filtered off must be
rapidly removed. In addition the intermediate claimed in U.S. Pat.
No. 6,458,949, again in acid form, is dried before subsequent
cyclization with thiourea, as this reaction is carried out in
water-tetrahydrofuran and it is advisable to remove methylene
chloride residues. Moreover the maximum obtainable yield is only
75%. U.S. Pat. No. 6,552,186 claims a compound of formula (IV)
6
[0011] in which X is halogen, R.sup.3 is trialkylsilyl and R.sup.2
is 7
[0012] This compound is reacted with silylated thiourea to provide
a compound of formula (I) in which R.sup.1 and R.sup.2 have the
aforesaid meanings and which on subsequent hydrolysis gives the
compound having the same formula (I) but in which R.sup.1 is H and
R.sup.2 is as aforestated: this compound is ceftriaxone.
[0013] U.S. Pat. No. 6,522,186 hence provides a compound of formula
(IV) in which R.sup.3 is trialkylsilyl. The corresponding
derivative in which R.sup.3 is however H had already been described
in U.S. Pat. No. 4,458,072 and obtained as an amorphous product
(column 16, line 49) without any indication of the yield, by a
laborious process using a precipitating agent such as petroleum
ether: this method is certainly unsuitable for industrial use.
Again, U.S. Pat. No. 6,552,186 says nothing about yields, as the
claimed process comprises direct obtaining of the silylated product
of formula (IV) and subsequent reaction with silylated thiourea to
give silylated ceftriaxone: the final passage to obtain ceftriaxone
disodium salt takes place by the known methods, however overall
total process yields are not given.
[0014] The recent U.S. Pat. No. 6,458,949 claims a process by which
Furaca is silylated and then reacted with a compound of formula
(III) 8
[0015] in which X is Cl or Br and Y is Cl, or
O--CH.dbd.N+(CH.sub.3).sub.2Cl.sup.-
[0016] to isolate an aforestated compound of formula (A), in which
X is Cl or Br and the carboxyl is free, non-salified and
non-esterified.
[0017] When reacted with thiourea in a partly aqueous solvent, this
intermediate produces ceftiofur.
[0018] Compounds of formula (III) have been known for some time:
for example, GB 2,012,276 describes in example 5 the preparation of
a compound of formula (III) in which the methoxyimino group is
substituted by the ethoxyimino group, X is Br and Y is Cl, by
reacting the corresponding acid having the same formula (III) but
in which X is Br and Y is OH, with PCl.sub.5 in a dichloromethane
solution. According to example 13 of the patent,
7-(4-chloro-3-oxo-2-methoxyiminobutyryl-amino)c- ephalosporanic
acid is subsequently reacted with thiourea to give a sodium salt of
7-[2-(2-aminothiazol-4-yl)-2-methoxyiminoacetamido)cephalosporani-
c acid, this being cefotaxime, EP 30294 (page 4, lines 36-37 and
40-45), U.S. Pat. No. 6,384,215 (column 3, lines 19-20) and U.S.
Pat. No. 6,458,949 (column 4, line 1; column 5, line 2 and lines
47-48) also describe the preparation of compounds of formula
similar to formula (III).
[0019] It is therefore apparent that compounds of formula (III) in
activated form, able to react with a compound of formula (II)
silylated at the carboxyl, can be prepared for example as chlorides
by reaction with PCl.sub.5 or other chlorinating agents, such as
POCl.sub.3 and DMF, in dichloromethane.
SUMMARY OF THE INVENTION
[0020] The object of the present invention is to provide a process
of high efficiency in terms of final product yield and purity, for
producing ceftiofur, cefotaxime, ceftriaxone, and cephalosporins
generally, characterised by the same general formula (I) 9
[0021] in which R.sup.1 is H or Na and R.sup.2 is chosen from the
group consisting of H, CH.sub.3, CH.sub.2OCH.sub.3,
CH.sub.2OCOCH.sub.3, CH.dbd.CH.sub.2, 10
[0022] According to this process, a compound of formula (II) 11
[0023] in which R.sup.2 has the aforestated meanings is silylated
at the carboxyl to give the corresponding trialkylsilyl-ester which
is reacted with a compound of formula (III) 12
[0024] in which X is Cl or Br and Y is Cl, or
O--CH.dbd.N.sup.+(CH.sub.3).sub.2 Cl.sup.-
[0025] to give a cephalosporin of formula (V) 13
[0026] in which X and R.sup.2 have the aforestated meanings, and
R.sup.3 is trialkylsilyl, which is hydrolyzed at pH 7.div.7.5 and
then treated in a partly aqueous solution with benzathine or a salt
thereof, to obtain crystallization of a new cephalosporin of
formula (V) 14
[0027] where Z is benzathine, in which the carboxyl is salified by
the benzathine, this salt being filtered off, washed with water and
reacted in a partly aqueous solvent with thiourea, to lead to the
formation of the 2-(2-aminothiazol-4-yl)-2-methoxyiminoacetic chain
and give a solution of the compound of general formula (I) in which
R.sup.2 has the aforestated meanings and R.sup.1 is H, the compound
of formula (I) being crystallized from this solution in the form of
the sodium salt, of the salt of a pharmaceutically acceptable
inorganic acid or of an internal salt.
[0028] Simultaneously with the formation of the
2-(2-aminothiazol-4-yl)-2-- methoxyyminoacetic chain there may be
the precipitation of benzathine hydrochloride which is filtered off
and removed to leave a very pure solution of the compound of
general formula (I).
[0029] In particular, it has been surprisingly found possible to
quantitatively isolate in aqueous solution a cephalosporin of
formula (V), in which R.sup.2 is CH.sub.2OCOCH.sub.3, or 15
[0030] without any interaction with the halogen atom X present in
the compounds of formula (V).
[0031] This precipitation, in aqueous solution automatically
eliminates all the acid impurities originating from the preparation
of the aforesaid compounds of formula (V), then by simply washing
with water a high purity moist product is obtained ready for
subsequent reaction with thiourea in a partly aqueous
environment.
[0032] A further considerable advantage of the present invention
derives from the fact that the cyclization reaction with thiourea,
leading to the formation of HCl, finds in benzathine a base able to
subtract it from the solution as the hydrochloride insoluble under
reaction conditions. In this manner a solution is obtained
containing only cephalosporin in acid form of such purity as to
enable it to be very easily crystallized as the sodium salt, by
adding a sodium salt such as sodium acetate or sodium
2-ethyl-hexanoate.
[0033] This succession of operations will be more apparent from the
non-limiting examples which follow.
[0034] However, the same operative scheme can evidently be applied
for the production of cephalosporins other than ceftiofur,
cefotaxime and ceftriaxone, having nuclei different from the
aforespecified three, but having the same
2-(2-aminothiazol-4-yl)-2-methoxyiminoacetic side chain in position
7.
DETAILED DESCRIPTION OF THE INVENTION
EXAMPLE 1
Preparation of Sodium Ceftiofur
[0035] Two separate solutions are prepared.
[0036] Solution A
[0037] 40 g of FURACA (MW 340.38-0.118 moles) and 336 ml of
tetrahydrofuran are fed into a dry 1 litre flask under a nitrogen
flow in the absence of direct light. The mixture is agitated for 15
minutes until homogenization, while cooling in the meantime to
+10.degree. C.
[0038] While maintaining the temperature at +10.degree.
C..div.+12.degree. C., 1.486 ml of trimethylchlorosilane (MW
108.64-d=0.859-0.1 eq) are quickly added. The mixture is agitated
for 5 min at +10.degree. C..div.+12.degree. C., and 45.43 g of
N,O-bis-trimethylsilyl-acetamide (MW 203.43-d=0.832-1.9 eq) are
added over 5.div.10 minutes.
[0039] The temperature is raised to +20.degree. C. and the mixture
agitated for 1 h35 min at 22.degree. C..div.23.degree. C. until a
solution is obtained. It is cooled to -35.degree.
C..div.-40.degree. C.
[0040] Solution B
[0041] 210 ml of ethyl acetate and 13.02 ml of
N,N-dimethylformamide (MW 73.094-0.169 moles-d=0.95-12.37 g) are
fed into a dry 1 litre flask under a nitrogen flow.
[0042] 15.49 ml of phosphorus oxychloride (POCl.sub.3) (0.167
moles-MW 153.33-d=1.675-25.95 g) are added at +25.degree. C.,
allowing the temperature to rise to +36.degree. C.
[0043] The mixture is cooled to 0.degree. C. and 27.62 g of
4-chloro-3-oxo-2-methoxyimino-butyric acid, commonly known as COMBA
(MW 179.56-0.154 moles) are added without exceeding +5.degree. C.
The mixture is agitated for 1 hour at +5.degree. C.
[0044] Solution B is added dropwise to solution A over 15 minutes
maintaining the temperature at -35.degree. C..div.-40.degree. C.
The reaction terminates within 2 hours at -35.degree.
C..div.-40.degree. C.
[0045] On termination of the reaction the mixture is poured into
500 ml of water at 0.degree. C., maintaining the pH at 7.0.div.7.5
with triethylamine, while maintaining the temperature at 0.degree.
C. 200 ml of ethyl acetate are added and the phases are separated
at 0.degree. C. .div.+5.degree. C. Extraction is again effected at
pH 7.0.div.7.5 with 350 ml of water.
[0046] The aqueous phase is decolorized at 0.degree.
C..div.+5.degree. C. for 30 minutes with 4 g of carbon and 0.4 g of
EDTA. It is filtered and washed with 150 ml of water.
[0047] The pH is adjusted to 7.0.div.7.5 with triethylamine at
0.degree. C..div.+5.degree. C. using a total of 110 ml thereof.
[0048] A mixture of 43.25 g of benzathine diacetate (0.120 moles)
dissolved in 350 ml of water is added dropwise, then washing with
50 ml of water.
[0049] It is left to precipitate cold at 0.degree.
C..div.+5.degree. C. for about 90 minutes.
[0050] The precipitate is filtered off and washed with 500 ml of
water divided into two portions. It is left to drip well.
[0051] The condensation product of 7-FURACA with activated COMBA,
precipitated moist as benzathine salt, is used as such in the next
passage.
[0052] A sample is dried for analysis.
[0053] The moist benzathine salt obtained as described is suspended
in 740 ml of tetrahydrofuran at +20.degree. C..div.+25.degree.
C.
[0054] It is cooled to 0.degree. C..div.+5.degree. C. and 19 ml of
triethylamine are added, maintaining this temperature. 12 g of
thiourea are added at 0.degree. C..div.+25.degree. C. and the
mixture agitated for 18 hours.
[0055] It is cooled to 0.degree. C..div.+5.degree. C. and, while
maintaining this temperature, 600 ml of ethyl acetate are added
plus about 20 ml of concentrated hydrochloric acid to pH 3. The
precipitated benzathine hydrochloride is filtered off and the
filter washed with a mixture of 60 ml of tetrahydrofuran +60 ml of
ethyl acetate.
[0056] 400 ml of water are added to the filtrate solution.
[0057] The temperature is raised to +10.degree. C..div.+15.degree.
C. and the pH adjusted to 8.0.div.8.5 with 15 ml of
triethylamine.
[0058] The phases are separated.
[0059] The impoverished organic phase is re-extracted with a
further 400 ml of water at pH 8.08.5, the aqueous phases are pooled
and washed with 300 ml of ethyl acetate. 400 ml of tetrahydrofuran
are added to the aqueous phase.
[0060] The mixture is cooled to 0.degree. C..div.+5.degree. C. and
the pH adjusted to 3 with 1N hydrochloric acid. 300 g of sodium
chloride are added and the mixture agitated until a solution forms,
while raising the temperature to +15.degree. C..div.+20.degree.
C.
[0061] The phases are separated, the overlying organic phase being
rich in product. Carbon is added to the organic phase at
+15.degree. C..div.+20.degree. C. and the mixture agitated for 20
minutes. The mixture is filtered and washed with 100 ml of
tetrahydrofuran.
[0062] A homogeneous mixture of 28.88 g of sodium 2-ethylhexanoate
and 100 ml of tetrahydrofuran is added dropwise to the decolorized
organic phase over 20 minutes.
[0063] The mixture is agitated for 15 minutes at +15.degree.
C..div.+20.degree. C.
[0064] The solution obtained is added dropwise over 30 minutes to
1000 ml of agitated tetrahydrofuran at +20.degree. C.
[0065] The mixture is agitated for 2 hours at +20.degree. C.,
filtered and washed with 320 ml of acetone.
[0066] The product is dried at +30.degree. C..div.+32.degree. C. to
obtain 51.3 g of sodium ceftiofur.
[0067] The dried sample of benzathine salt has the following
general formula (V), and more specifically has the general formula
16
[0068] which provides the following spectra:
[0069] .sup.1HNMR in DMSO-d.sub.6 300 Mhz; Hc=9.40 ppm 1H; Hn=8.04
ppm 1H; Hu-Hv=7.32-7.46 ppm 10H; Hl=7.39 ppm 1H; Hm=6.77 ppm 1H;
Hd=5.68 ppm 1H; He=5.06 ppm 1H; Hq-Hr=4.84 ppm 3H; Hb=3.95 ppm 3H;
Hh-Hi=4.22-3.99 ppm 2H; Hf-Hg=3.65-3.26 ppm 2H; Hs-Ht=4.03 ppm 4H;
Ho-Hp=2.95 ppm 4H; Ha=3.97 ppm 2H.
[0070] FT-IR (cm.sup.1); 1777.6-1717.1-1650.7-1565.8
EXAMPLE 2
Preparation of Ceftriaxone Disodium Salt
[0071] Two separate solutions are prepared.
[0072] Solution A
[0073] 15.57 g of 7-ACT (MW 371.39-0.042 mol) and 155 ml of
methylene chloride are fed into a dry 1 litre flask under a
nitrogen flow in the absence of direct light. The mixture is cooled
to +10.degree. C. and 34.11 g of N,O-bis-trimethylsilyl-acetamide
are added, a slight amount of heat being produced. The mixture is
agitated at +20.div.22.degree. C. and after 45 minutes a complete
solution is obtained. The mixture is cooled to -40.degree. C.
[0074] Solution B
[0075] 80 ml of ethyl acetate and 4.69 ml of N,N-dimethylformamide
(MW 73.09, d=0.95) are fed into a dry 1 litre flask under a
nitrogen flow at +25.degree. C. 5.58 ml of phosphorus oxychloride
(MW 153.33, d=1.675, 9.34 g) are added allowing the temperature to
rise to 36.degree. C. (if this temperature is not attained within
20.div.25 minutes, heating is required). The mixture is cooled to
0.degree. C. then 9.94 g of 4-chloro-3-oxo-2-methoxyimino-butyric
acid, commonly known as COMBA (MW 179.56) are added. The mixture is
agitated at +5.degree. C. for 1 hour. Solution B is added dropwise
to solution A over 15.div.20 minutes maintaining the temperature at
-35.degree..div.-40.degree. C. and washing the flask with 15 ml
ethyl acetate. The mixture is agitated for 10 minutes at
-35.degree..div.-40.degree. C. and the reaction goes to completion.
The reaction mixture is poured into a mixture of 50 ml water, 320
ml isopropanol and 270 ml of a saturated aqueous solution of sodium
bicarbonate pre-cooled to 0.degree..div.+5.degree. C. without
exceeding +5.degree. C. It is agitated for 2 hours at
0.degree..div.+5.degree. C. maintaining the pH at 2.5 (consuming
about 27 ml of 17% hydrochloric acid), the pH being checked for
about 90 minutes, during which any necessary correction is done
with solid sodium bicarbonate. The phases are separated and the
underlying aqueous phase is retained. The rich organic phase is
washed with 25 ml water, then with a solution of 22 g NaCl in 80 ml
water. The aqueous phases are retained each time and pooled, then
re-extracted with 40 ml methylene chloride. The organic phases are
pooled and the spent aqueous phase is discarded. The former is
decolorized under agitation for 15 minutes with 1.5 g carbon,
filtered and the filter is washed with 30 ml of methylene chloride.
150 ml of water are added to the decolorized organic phase at
0.degree..div.+5.degree. C. followed by, still at
0.degree..div.+5.degree- . C., a solution of 11.21 g anhydrous
sodium acetate in 100 ml water pre-cooled to
0.degree..div.+5.degree. C. After 30 minutes the phases are
separated allowing the temperature to rise to about +20.degree. C.
The poor organic phase is re-extracted with 100 ml of water,
facilitating separation with 50 ml of methylene chloride. The
aqueous phases are pooled and decolorized at +20.degree. C. for 30
minutes with 1.5 g of carbon, 0.150 g of EDTA and 0.200 g of
celite. The mixture is filtered and the filter is washed with 100
ml water.
[0076] A solution of 15.14 g of benzathine diacetate in 160 ml
demineralised water is added over 15 minutes to the decolorized
solution at 15.degree..div.20.degree. C. The mixture is agitated
for 30 minutes at 15.degree..div.20.degree. C., cooled to
0.degree..div.+5.degree. C. and agitated for 1 hour. It is filtered
and washed 3 times with 50 ml of water. It is thoroughly squeezed
under a nitrogen flow to obtain 28.52 g of the benzathine salt of
the condensation product of 7-ACT with COMBA. A sample is dried for
analysis.
[0077] The dried sample of benzathine salt has the general formula
(V), and more specifically has the formula 17
[0078] which provides the following spectra:
[0079] .sup.1HNMR in DMSO-d.sub.6 300 MHz: Hc=9.36 ppm 1H;
Hu-Hv=7.30-7.42 ppm 10H; Hd=5.65 ppm 1H; He=5.03 ppm 1H;
Ha-Ha'=4.84 ppm 3H; Hb=4.03 ppm 3H; Hq-Hr=3.91 ppm 3H;
Hh-Hi=4.35-4.12 ppm 2H; Hm=3.50 ppm 3H; Hf-Hg=3.62-3.39 ppm 2H;
Hs-Ht=3.53 ppm 4H; Ho-Hp=2.89 ppm4H.
[0080] FT-IR (cm.sup.-1): 1775.1-1715.7-1666.6-1594.1
[0081] The benzathine salt obtained is suspended in 200 ml water
and 142 g of the sulfonic resin Resindion UBK 530 in sodium form
and 6.38 g of thiourea are added at 20.degree..div.25.degree. C.
The mixture is agitated for 4 hours at 20.degree..div.25.degree.
C., filtered and washed 8 times with 50 ml of water each time and
then decolorized for 20 minutes at 15.degree..div.20.degree. C.
with 1.5 g of carbon, 0.150 g of EDTA and 0.200 g of celite. The
carbon is filtered off and the filter is washed 4 times with 50 ml
water. The pH is adjusted to about 4.2 with 7 ml of 17%
hydrochloric acid at 15.degree./20.degree. C., until precipitation
begins. It is agitated for 30 minutes, and adjusted to pH 3 over 40
minutes at 15.degree..div.20.degree. C. with about 13 ml of 0.17%
hydrochloric acid.
[0082] It is filtered off, washed twice with 50 ml water and
thoroughly squeezed to obtain 45 g of crude ceftriaxone acid
(K.F.=about 60%).
[0083] 79.5 ml of acetone, 20 ml of water, 80 g of carboxylic resin
RELITE CNS (activated in sodium form) are fed into a flask. The
mixture is cooled to +10.degree. C. and 45 g of well-sifted crude
ceftriaxone acid obtained above are added, then agitated at
+10.degree. C. for 4 hours until the dissolved ceftriaxone content
remains constant. The resin is filtered off, washed with a mixture
of 10 ml water+8 ml acetone and then with a mixture of 6 ml water
and 19 ml acetone, maintaining these washes separate from the
initial filtrate and at +10.degree. C. The initial filtrate is
maintained under agitation with 1.33 g carbon, 0.07 g EDTA and 0.13
g celite, for 45 minutes at +10.degree. C. This is filtered off and
washed with the mixture of the two washes kept separate from the
initial filtrate, the decolorized solution being diluted with 79.5
ml acetone added dropwise over 10 minutes at +10.degree. C. It is
seeded with disodium ceftriaxone and agitated for 90 minutes at
+10.degree. C. 291.5 ml of acetone are then added dropwise over 3
hours at +10.degree. C. The product is filtered off and washed with
106 ml portions of acetone, thoroughly squeezed under a nitrogen
flow then dried at ambient temperature until constant weight, to
obtain 22.5 g disodium ceftriaxone.
EXAMPLE 3
Preparation of Cefotaxime Sodium Salt
[0084] Two separate solutions are firstly prepared.
[0085] Solution A
[0086] 64 g of 7-ACA (MW 272.28-0.235 mol) and 400 ml of
tetrahydrofuran are fed into a dry 1 litre flask under a nitrogen
flow and in the absence of direct light. The mixture is agitated
for 15 minutes until homogenized while cooling to +15.degree.
C.
[0087] 191.34 g of N,O-bis-trimethylsilyl-acetamide (MW 203.43,
d=0.832, 0.941 mol) are quickly added, maintaining the temperature
at 20.degree..div.25.degree. C. The temperature is maintained at
20.degree..div.25.degree. C. while the mixture is agitated for 15
minutes at +20.degree..div.+25.degree. C. until dissolved, then
cooled to -35.degree. C..div.-40.degree. C.
[0088] Solution B
[0089] 420 ml of ethyl acetate and 26.04 ml of
N,N-dimethylformamide (MW 73.09, d=0.95, 0.338 mol, 24.74 g) are
fed into a dry 1 litre flask under a nitrogen flow at +25.degree.
C. 30.98 ml of phosphorus oxychloride (MW 153.33, d=1.675, 51.9 g)
are added allowing the temperature to rise to 36.degree. C. (if
this temperature is not attained in 20.div.25 minutes, heating is
required). The mixture is cooled to 0.degree. C. then, without
exceeding +5.degree. C., 55.24 g of
4-chloro-3-oxo-2-methoxyimino-butyric acid, commonly known as COMBA
(MW 179.56-0.308 mol) are added. The mixture is agitated at
+5.degree. C. for 1 hour. Solution B is added dropwise into
solution A over 15.div.20 minutes while maintaining the temperature
at -35.degree..div.-40.degree. C.
[0090] The reaction terminates within about 45 minutes at
-35.degree..div.-40.degree. C. At the end of the reaction 600 ml of
water at 0.degree. C. are poured in, adjusting the pH to 7.div.7.5
with triethylamine and maintaining the temperature at
0.degree..div.+5.degree. C.
[0091] The organic phase is extracted again with 450 ml of water at
0.degree..div.+5.degree. C., maintaining the pH at 7.div.7.5.
[0092] The aqueous phases are pooled and a solution of 85.05 g of
benzathine diacetate in 800 ml of water is added dropwise over 60
minutes, maintaining the temperature at 0.degree..div.+5.degree. C.
It is agitated for 1 hour at 0.degree..div.+5.degree. C., the
product is filtered off then washed twice with 250 ml water and
thoroughly squeezed. 152 g of moist condensation product of 7-ACA
with COMBA as the benzathine salt are obtained.
[0093] A sample is dried for analysis.
[0094] The dried sample of benzathine salt has the general formula
(V) and more specifically has the formula 18
[0095] which provides the following spectra:
[0096] .sup.1HNMR in DMSO-d.sub.6 300 MHz: Hc=9.42 ppm 1H;
Hu-Hv=7.36-7.46 ppm 10H; Hd=5.73 ppm 1H; He=5.03 ppm 1H; Hq-Hr=4.85
ppm 3H; Hb=3.95 ppm 3H; Hh-Hi=4.11-4.03 ppm 2H;
[0097] Hf-Hg=3.55-3.36 ppm 2H; Hs-Ht=3.99 ppm 4H; Ho-Hp=3.05 ppm
4H; Ha=2.03 ppm 2H.
[0098] FT-IR (cm.sup.-1): 1766.3-1719.5-1660.0-1555.8
[0099] The moist product obtained is suspended in a mixture of 320
ml of tetrahydrofuran and 80 ml of water, cooled to
0.degree..div.-5.degree. C. and 22 ml of triethylamine are added to
pH 7.5. 24.84 g of thiourea are added and left to react for 4 hours
at +20.degree..div.+25.degree. C. until conversion of the
aforestated condensation product to cefotaxime is complete.
[0100] On termination of the reaction 1.6 g of sodium hydrosulfite,
0.4 g of EDTA, 0.8 g of celite and 4 g of carbon are added and the
mixture is agitated for 20 minutes then filtered, washing the
product with 80 ml of tetrahydrofuran. The tetrahydrofuran is
evaporated under reduced pressure until an oily residue forms. 368
ml of water are added dropwise to the oil obtained under
agitation.
[0101] 233.6 g of 99% formic acid are dropped over a period of
5.div.10 minutes at +15.degree..div.+20.degree. C. into the
suspension obtained.
[0102] It is cooled to 0.degree..div.+5.degree. C. and agitated for
3 hours, filtered and the product washed with 96 ml of water
pre-cooled to 0.degree..div.+5.degree. C. The product is suspended
in 384 ml of ethanol at 45.div.50.degree. C. and agitated for 1
hour. It is filtered off while hot then washed with 192 ml of ethyl
acetate.
[0103] After drying, 36 g of cefotaxime ethanol solvate with a
concentration of 85% is obtained, serving as intermediate.
[0104] 227.5 ml of methanol, 28.2 ml of water and 32.8 g of sodium
2-ethylhexanoate are fed into a flask under a nitrogen flow. The
mixture is agitated at ambient temperature until completely
dissolved and cooled to 0.degree..div.+5.degree. C. The
intermediate cefotaxime acid ethanol solvate (87.5 g) is added and
complete dissolution is achieved at 0.degree..div.+5.degree. C. The
temperature is maintained and 350 ml of ethyl acetate are added
over 1 hour. The solution is seeded with cefotaxime sodium salt and
agitated for 1 hour at 0.degree..div.+5.degree- . C. A further 263
ml of ethyl acetate are added over 40 minutes, then a further 875
ml of ethyl acetate over 1 hour at 0.degree..div.5.degree. C. The
mixture is agitated for 30 minutes at the same temperature,
filtered and the product washed with 88 ml ethyl acetate and dried
at 30.degree. C. under reduced pressure. Yield: 80.5 g of
cefotaxime sodium salt.
EXAMPLE 4
Preparation Of Ceftiofur Hydrochloride
[0105] Two separate solutions are prepared.
[0106] Solution A
[0107] 20 g of Furaca (MW 340.38-58.76 mmol) and 168 ml of
tetrahydrofuran are fed into a dry 1 litre flask under a nitrogen
flow and in the absence of direct light. The mixture is agitated
for 15 minutes until homogenized while cooling to +10.degree. C. At
+10.degree..div.+12.degree. C. 0.743 ml of trimethylchlorosilane
(MW 108.64-d=0.859) are quickly added. The mixture is agitated for
5 minutes at +10.degree..div.+12.degree. C. and then 22.72 g BSA
(MW=203.43) are added over 5.div.10 minutes.
[0108] The temperature is raised to +20.degree. C. and the mixture
is agitated for 95 minutes at +22.degree..div.+23.degree. C. until
completely dissolved. It is then cooled to
-35.degree..div.--40.degree. C.
[0109] Solution B
[0110] 105 ml of ethyl acetate and 6.51 ml of dimethylformamide (PM
73.09, d=0.95) are fed into a dry 1 litre flask under a nitrogen
flow. At +25.degree. C. 7.75 ml of POCl.sub.3 (MW 153.33, d=1.675)
are added, allowing the temperature to rise to +36.degree. C. over
20.div.25 minutes, if necessary heating it slightly. The mixture is
cooled to 0.degree. C. and then 13.81 g of
4-chloro-3-oxo-2-methoxyimino-butyric acid, commonly known as COMBA
(MW 179.56) are added taking care not to exceed +5.degree. C.
Agitation is maintained at +5.degree. C. for 60 minutes.
[0111] Solution B is added dropwise into solution A over 15
minutes, maintaining the temperature at -35.degree..div.-40.degree.
C. It is left to react for 2 hours at the same temperature.
[0112] On termination of the reaction the reaction mixture is
poured into 100 ml of iced water, correcting the pH to 3.0 with
about 20 ml of triethylamine and maintaining the temperature at
0.degree..div.+5.degree. C. The temperature is raised to
+15.degree..div.+20.degree. C. and the phases are separated. The
aqueous phase is again extracted with 100 ml of ethyl acetate, the
organic phases are pooled and decolorized with 2 g of carbon
maintaining agitation for 20 minutes at 15.degree..div..degree. C.
The latter is filtered off, the filter is washed with 25 ml of
tetrahydrofuran and then with 25 ml of ethyl acetate.
[0113] The solution is cooled to 0.div.+5.degree. C. and 200 ml
water at 0.div.+5.degree. C. are added. At the same temperature the
pH is corrected to 8 with about 13 ml of triethylamine.
[0114] The phases are separated and extracted twice more with 100
ml water maintaining the pH at 8 with 3 ml of triethylamine. The
aqueous phases are pooled and a solution of benzathine diacetate
(27.75 g, MW 360.4) in 262.5 ml water is added dropwise over 30
minutes, at 0.degree..div.+5.degree. C., then the remaining
benzathine solution left in the dropping funnel is recovered,
washing it with water (37.5 ml). Agitation is maintained for 2
hours at 0.degree..div.+5.degree. C., then the product is filtered
off and allowed to well drain, then finally washed 4 times, each
time with 50 ml of water. 112 g of intermediary product as moist
benzathine salt are obtained, with a K.F. of about 60%.
[0115] The moist product with the aforestated K.F., is suspended in
tetrahydrofuran (250 ml) at +20.degree.25.degree. C. 200 g of
UBK530 resin in sodium form and 5.86 g of thiourea are added in the
stated order to the suspension obtained, the pH then being
corrected to 8.0.div.8.5 with triethylamine (2.5 ml).
[0116] Agitation is maintained for 3 hours at
20.degree..div.25.degree. C., then further triethylamine (3.5 ml)
is added to correct the pH to 7.5.div.8.0. After further agitation
for 20 hours at 20.degree..div.25.degree. C., a final reaction pH
of 2.5.div.3.0 is achieved. The resin is filtered off and washed
with 2.times.50 ml portions of tetrahydrofuran, then twice with a
mixture of 25 ml tetrahydrofuran+25 ml of ethyl acetate and finally
with 25 ml of water.
[0117] Triethylamine (7.5 ml) is added to achieve pH 8.0.div.8.5
and then ethyl acetate (200 ml). The phases are separated and the
aqueous phase is decolorized with 2 g of carbon, adding 0.2 g of
EDTA and 0.2 g of celite and agitating for 20 minutes.
[0118] The organic phase is re-extracted with 100 ml of water,
which is used to wash the filter following decolorization, whereas
the organic phase is finally removed.
[0119] 125 ml of tetrahydrofuran are added to the decolorized
aqueous phase, cooled to 0.degree..div.+5.degree. C. and the pH
corrected to 3 with about 60 ml of 1N HCl. 50 g of sodium chloride
are then added at the same temperature, the mixture is heated to
+15.degree..div.+20.degree. C. and the phases are separated.
[0120] Water (250 ml) is added to the organic phase and the pH is
adjusted to 8.0.div.8.5 with triethylamine (about 12.5 ml), then
ethyl acetate (250 ml) is added.
[0121] The phases are again separated, the organic phase is
re-extracted with water (150 ml) at pH 8.0.div.8.5 The aqueous
phases are pooled, washed 3 times with ethyl acetate (200 ml each
time), the aqueous phase is decolorized with 2 g of carbon +0.2 g
EDTA+0.2 g celite.
[0122] This is filtered off and washed with water (100 ml), the
solution is cooled to 0.degree..div.+5.degree. C. and the pH is
adjusted to 3 with about 48 ml of 1N HCl. It is agitated while cold
for 1 hour, the product is filtered off and washed twice with 100
ml water. It is left to drip well under nitrogen, to obtain 114 g
of moist product.
[0123] The moist solid is suspended in tetrahydrofuran (125 ml) and
agitated at 20.degree. C. until dissolution is virtually complete,
after about 30 minutes, then a saturated aqueous solution (50 ml)
of sodium chloride is added and further agitated until complete
homogenisation of the mixture.
[0124] The phases are separated. The organic phase is decolorized
with 2 g carbon at 20.degree. C., filtered and washed with 50 ml
tetrahydrofuran. It is cooled to 0.degree..div.+5.degree. C., the
pH is corrected to 0.5 with concentrated HCl (about 5.5 ml) and
maintained under agitation for 10 minutes at
0.degree..div.+5.degree. C.
[0125] The acid solution is added dropwise over 45 minutes to 1500
ml acetone while agitated at 20.degree. C. Agitation is continued
for a further 60 minutes at 20.degree. C., then the mixture is
cooled to 0.degree./+5.degree. C. and again agitated for a further
60 minutes. The product is filtered off and washed with 150 ml
acetone to obtain 29 g of moist product.
[0126] It is dried at 20.degree. C. to obtain 20.5 g of ceftiofur
hydrochloride. 19
[0127] Ceftiofur Hydrochloride .sup.1HNMR
[0128] 9.79 ppm doublet Jcd=8.1 Hz Hc
[0129] 8.06 ppm Hn ddd system abc
[0130] 7.44 ppm Hm ddd system abc
[0131] 6.91 ppm Hl ddd system abc
[0132] 6.76 ppm singlet Ha
[0133] 5.76 ppm Hd dd Jcd=8.1, Jde=5.16 Hz
[0134] 5.16 ppm He doublet Jde=5.16 Hz
[0135] 4.27 ppm, 3.93 ppm Hh, Hi system ab two doublets Jhi=13.2
Hz
[0136] 3.74 ppm, 3.38 ppm Hf, Hg two doublets system ab
[0137] Jfg=17.6 Hz
[0138] 3.92 ppm Hb singlet
[0139] Ceftiofur Hydrochloride FT-IR
[0140] amide NH stretching 3273 cm.sup.-1
[0141] lactam C.dbd.O 1766.3 cm.sup.-1
[0142] thioester C.dbd.O 1709.0 cm.sup.-1
[0143] carboxyl C.dbd.O 1659.4 cm.sup.-1
[0144] amide C.dbd.O 1629.4 cm.sup.-1
* * * * *