CS262698B2 - A method for producing thermally stable crystalline cephalosporins - Google Patents

Abstract

A process for the preparation of stable crystalline cephalosporins of the general formula (yilb) wherein X is hydrogen iodide or hydrogen chloride and -Nu is a pyridinium, N-methylmorpholinium, N- methylpyrrolidinium or 2,3-cyclopentenopyridinium radical characterized in in 1,1,2-trichlorotrifluoroethane, it acts in any order with iodotrimethylsilane and pyridine, N-methylmorpholine, N-methylpyrrolidine or 2,3-cyclopentenopyridine; .odod. The compounds produced serve as intermediates for the preparation of broad-spectrum cephalosporin antibiotics.

Description

A method for producing stable crystalline cephalosporins of the general formula yilb, where X is hydrogen iodide or hydrogen chloride and —Nu represents a pyridinium, N-methylmorpholinium, N-methylpyrrolidinium or 2,3-cyclopentenopyridinium residue, characterized in that a solution of the compound of the formula Via in 1,1,2-trichlorotrifluoroethane is treated in any order with iodotrimethylsilane and pyridine, N-methylmorpholinium, N-methylpyrrolidine or 2,3-cyclopentenopyridine, the silyl groups are removed from the product by the action of a lower alkanol and the product is acidified with hydrogen chloride or hydrogen iodide. The compounds produced serve as intermediates for the preparation of cephalosporin antibiotics with a broad spectrum of activity.

The invention relates to temperature-stable crystalline salts of cephalosporin derivatives of the general formula VIIb

Χ.Η,Ν·^ _X S ni

CR,-N:a coo (V i ib) where

X represents hydrogen chloride or hydrogen iodide and + —Nu represents the remainder of the formula

in which

B ¹ represents a hydrogen atom or a conventional protecting group of the carboxyl function, and their N-silyl derivatives.

In the above-cited patent specification, these compounds are not illustrated by examples, but are merely described by structural formulas as intermediates for an alternative reaction sequence for the preparation of certain cephalosporins (acylation followed by removal of the protecting group from the carboxyl function). The examples illustrating this reaction sequence do not use the above-mentioned compounds (and also require removal of the protecting group from the carboxyl function as a final reaction step). All of the final products described in U.S. Patent No. 4,406,899 require the inclusion of chromatographic purification to separate the resulting mixture of A ² - and A ³ -isomers.

U.S. Patent No. 4,168,309, issued September 18, 1979 to Earry E. Ayres, discloses compounds of the formula

These compounds are in the A ² -Isomer and can be converted to cephalosporin antibiotics without the need to cleave the protecting group of the carboxyl function.

The actual subject of the invention is a process for producing salts of the above-mentioned general formula VIIb.

U.S. Patent No. 4,406,899, issued August 27, 1983 (Aburaki et al.), discloses compounds of the general formula

where

Ph stands for phenyl group and compounds of the general formula

in which

R"' represents a protecting group of the carboxyl function,

R ¹ together with the carbon atoms to which it is attached forms an optionally substituted saturated or partially saturated four- to ten-membered heterocyclic ring which may contain one or more additional heteroatoms selected from the group consisting of oxygen, nitrogen and sulfur, the dashed line represents either a cef-2-em- or cef-3-em derivative and

X ^- represents an anion, and their acid addition salts and N-silylated derivatives.

In the cited patent specification, these compounds are not illustrated by examples, but are described only by structural formulas as intermediates for an alternative synthesis of certain cephalosporins (by acylation and then cleavage of the carboxyl group). The examples illustrating this synthesis do not use these compounds (and also require the removal of the carboxyl protecting group as a final reaction step).

The use of protected carboxyl functions in the processes according to both of the above-cited patents is disadvantageous because it requires the removal of the protecting groups after the acylation, which also partially removes the acyl residue, so that the yield achieved is lower than 100%.

U.S. Patent No. 4,223,135, issued September 16, 1980 (Derek Walker et al.), describes compounds of the general formula

in which

B represents a chlorine atom, a methoxy group or a residue —CH2E, where E represents hydrogen, a group —OCCH3, —OCNH2 or —SZ,

II II o o in which Z represents an optionally substituted five- or six-membered heterocyclic ring containing 2 to 4 nitrogen atoms and optionally 1 oxygen or sulfur atom, wherein the sulfur atom in the group —SZ is bonded to a carbon atom of the heterocyclic ring in the meaning of the symbol Z and

A represents a trimethylsilyl group or an easily cleavable ester protecting group.

These compounds are prepared by adding dry carbon dioxide to a solution of a compound of the general formula

in which

A and B have the meanings given above, in an inert organic solvent, which is preferably methylene chloride.

U.S. Patent No. 4,316,017, which was granted as a continuation-in-part of U.S. Patent No. 4,223,135, has substantially the same description.

U.S. Patent No. 4,336,253, issued June 22, 1982 (Willam H. W. Lunn), describes compounds of formula I

long

......

and their preparation by reacting a compound of general formula II

N.....—~r

C-CONH

II

N.

O

STEED

OCCH ₃ cooh til} with a silylating agent such as trimethylsilylacetamide, bistrimethylsilylacetamide, etc., leading to the formation of a compound of general formula III

SiHN

by reacting a compound of general formula III with trimethylsilyl iodide to form a compound of general formula IV

N

C~ CONH- j- -/'

J-WV 'CH,1 ^0R COQSiJCHJ.

itV) which is then reacted with a compound of the general formula to form a compound of the general formula I.

Chlorinated hydrocarbons and lower alkyl nitriles are reported as solvents suitable for the reactions leading to the formation of compounds of formulae III and IV.

U.S. Patent Nos. 4,379,787, 4,382,931 and 4,382,932 (William H. W. Lunn et al.) relate to analogous compounds and processes where R is, for example, an amino-substituted oxazole, oxadlazole or isoxazole ring and the substituent at position 3 is, for example, an optionally substituted pyridine, quinoline or isoquinoline residue.

South African patent application number 84/3343, published on 25 October 1984, describes a process for the production of cephalosporins of general formula I.

in which

R represents a thiazolyl or 1,2,4-thiadiazolyl radical,

R ¹ represents a hydrogen atom or a methoxy group,

R ² represents any of the numerous substituents known from cephalosporin chemistry and

A represents an optionally substituted quinolinium or pyridinium radical.

The compounds of the above general formula I are prepared by reacting a compound of the general formula II

in which

R ⁸ represents a hydrogen atom or a protecting group of the amino function and

R ⁷ represents a group which can be replaced by the action of a base corresponding to the residue A, is reacted with a base corresponding to the residue A in the presence of a trialkyliodosilane, to form a compound of general formula III

R<

r ⁸ nh--4 o | yy coo“ , lnu which is then (after removal of the protecting group of the amino function) acylated with an acid of general formula IV

R—C—COOH

OR ²

Suitable R ⁷ groups reported include acetoxy, propionyloxy, chloroacetoxy, acetylacetoxy and carbamoyloxy. Suitable solvents include the following: methylene chloride, chloroform, dichloroethane, trichloroethane, carbon tetrachloride, acetonitrile, propionitrile and free radicals. The most preferred solvent is methylene chloride.

In the above-cited patent it is acknowledged that the above general procedure is known, but that the inventors have found that surprisingly high yields can be achieved if the nucleophilic substitution reaction of the compound of general formula II (leading to the compound of general formula III) is carried out by first adding an excess (up to a twenty-fold excess) of the base corresponding to the residue A and then a trialkyliodosilane in an amount up to a ten-fold excess.

In the published German patent application No. P 3316798.2, filed on 7 May 1983, from which the Union priority is claimed for the above-cited South African patent specification, the same solvents are listed as above, with the only exception that the term "frigen" is used instead of the term "frigand". In the 10th edition of the Merck Index, the preparations Frigen 11, Frigen 12 and Frigen 114 are listed as other names for the preparations Freon 11, Freon 12 and Freon 114, which are trichlorofluoromethane, dichlorodifluoromethane and 1,2-dichloro-1,1,2,2-tetrafluoroethane, respectively.

The compounds of the above-mentioned general formula VIIb, which are prepared by the process according to the invention, are crystalline, thermally stable and practically free of the corresponding A ² -isomer. Due to the absence of this A ² -isomer, the above-mentioned compounds can be converted by acylation into a wide variety of cephalosporins, which are also practically free of the A ² -isomer and in which it is therefore not necessary to carry out chromatographic separation ^{of the 2} A- and A ³ -isomers. Due to the thermal stability of the compounds according to the invention, these substances can be isolated and stored, and converted into the resulting products only when desired. Another advantage of the compounds of the general formula VIIb is that they do not require protection of the carboxyl group before acylation and, as a result, it is not necessary to remove the protecting group of the carboxyl function after acylation, which improves the efficiency of the entire process.

In accordance with the invention, the compounds of general formula VIIb are prepared by adding to a solution of the compound of general formula IVa

(IV&A in 1,1,2-trichlorotrifluoroethane reacts in any order with at least one equivalent of iodotrimethylsilam and at least one equivalent of a compound of the general formula

The silyl groups are removed from the resulting product by treatment with a lower alkanol and the product is acidified with hydrogen chloride or hydrogen iodide.

According to one embodiment of the method according to the invention, a solution of the compound IVa is prepared by

AND

Oh my;

CH-GC CH (IVáJ in 1,1,2-trichlorotrifluoroethane reacts with trimethylsilyl iodide (iodotrimethylsilane). This solvent surprisingly leads to the formation of the compound of formula lita below, which is practically free of the A ² -isomer, while the use of similar conventional solvents, for example 1,2-dichloroethane, gives the compound of formula lila containing a significant amount (for example 25%) of the undesirable A ² -isomer. The use of other conventional solvents, such as chlorobenzene, dioxane, carbon tetrachloride and the like, also leads to the formation of significant amounts of the undesirable A ² -isomer.

The above reaction is carried out at a temperature of about 5 ^° C to 45°C, conveniently at room temperature. At least one equivalent of trimethylsilyl iodide is required to convert the entire amount of compound of formula IVa into compound of formula IIIa. In practice, about 0.9 to 1.5, most preferably about 1.0 to 1.2 equivalents of trimethylsilyl iodide are used for each equivalent of compound of formula IVa.

The resulting compound corresponds to the formula lilac

( CHJ.,Sí.hN~~ o

CQ^ScíCH^ (Uláj) is then reacted with the above-mentioned nucleophiles in 1,1,2-trichlorotrifluoroethane to form a compound of the general formula Ha below. Surprisingly, it was found that when 1,1,2-trichlorotrifluoroethane is used as a solvent, the compound of formula Ha is formed practically free of the A ² -isomer, while the use of conventional solvents such as methylene chloride, tetrahydromethane, chloroform or dioxane leads to the formation of a compound of formula II containing a large amount of the undesired A ² -isomer (for example 50% A ² -isomer).

The reaction is carried out at a temperature of about -10°C to 25°C, preferably about 0°C to 10°C. Although larger or smaller amounts of nucleophile may be used, the purest product is obtained when about 1 equivalent of nucleophile is used for each equivalent of compound of formula IIIa.

For the solution of the resulting formula Ila compounds general (CHJ, SLHN-r— w *»> ς τη -£ - „M Λ .* 0 í ‘ ’ >?. what, sic:

in 1,1,2-trichlorotrifluoroethane (Freon TF) is then treated with a lower alkanol or water to remove the trimethylsilyl groups and then with hydrogen chloride or hydrogen iodide to form the hydrochloride or hydroiodide. A lower alkanol, most preferably methanol, is preferably used to cleave the trimethylsilyl groups. The reaction is carried out at a temperature of about -10°C to 25°C, preferably at a temperature of about 0 to 10°C. For each equivalent of the compound of formula IIa, about 2 to 5 equivalents of methanol are used, preferably about 3 to 4 equivalents of methanol.

According to an alternative method for preparing the compound of formula IIa, a nucleophile is first added to a solution of the compound of formula IVa in 1,1,2-trichlorotrifluoroethane, followed by at least 1 equivalent of trimethylsilyl iodide. This reaction can be carried out at a temperature of about 5 to 45°C, and is conveniently carried out at a temperature of about 35°C. The nucleophile can be used in an amount of about 1.0 to 2.0 equivalents per equivalent of the compound of formula IVa, preferably in an amount of about 1.2 to 1.5 equivalents. The trimethylsilyl iodide is about 1.5 to 2.0 equivalents per equivalent of the compound of formula IVa.

The compound of formula IVa can be prepared by reacting 7-aminocephalosporanic acid (7-ACA), i.e. the compound of formula V

H ₂ Nr—S ₀

COgH (V!

with hexamethyldisilazane in the presence of about 0.01 to 0.1 equivalent of trimethylsilyl iodide per equivalent of 7-aminocephalosporanic acid, in 1,1,2-trichlorotrifluoroethane or methylene chloride, at a temperature from room temperature to the boiling point of the solvent. The reaction is preferably carried out at reflux. Hexamethyldisilazane can be used in an amount of about 0.95 to 1.4 equivalents per equivalent of 7-aminocephalosporanic acid, preferably about 1.0 to 1.3 equivalents, and most preferably in an amount of 1.2 equivalents per equivalent of 7-aminocephalosporanic acid.

The entire process according to the invention is preferably carried out in a single reaction vessel, i.e. without isolation of intermediates.

When carrying out the above-described reaction sequence, it was found that rather than proceeding via the corresponding 3-chloromethyl derivative or 3-bromomethyl derivative, it was necessary to proceed via the 3-iodomethyl derivative of formula IIIa. Surprisingly, it was found that the reaction of the compound of formula IVa with trimethylsilyl chloride or trimethylsilyl bromide produces a smaller amount of the expected 3-chloromethyl or 3-bromomethyl analogue of the compound of formula IIIa, for example, even after heating to reflux for ten days, a maximum of about 5 to 15%.

Compounds of general formula VIIb can be readily converted into a wide variety of antibiotics by acylation with the appropriate side chain-forming acid. For example, a preferred compound of general formula VIIb, +

wherein —Nu represents an N-methylpyrrolidinium radical and X has the meaning given above (compound of general formula I) is converted to 7-[α-(2-aminothiazol-4-yl)-α-(Z)-methoxyiminoacetamido]-3-[(1-methyl-1-pyrrolidinio)methyl]-3-cephem-4-carboxylate of formula VIII by N-acylation with an activated ester, which is 1-benzotriazolyl 1-(Z)-2-(2-aminothiazol-4-yl)-2-methoxyiminoacetate, according to the following reaction scheme:

OCONH li

N.

.WITH.

\

OC i—i

..\to

COO (Vlil)

This reaction is easily carried out in the presence of N,N-dimethylaniline in dimethylformamide at room temperature and for a reaction time ranging from 10 to 20 hours, or by dissolving the compound of formula I in water and dimethylformamide, adding sodium bicarbonate to the solution under ice-cooling, and

262693 the mixture is allowed to react at room temperature for about 30 minutes to 5 hours, or by dissolving the compound of formula I in water, cooling the solution to 5 to 15 °C, adjusting the pH to 5.5 to 6 by dropwise addition of sodium hydroxide, adding tetrahydrofuran, adjusting the pH to 6.7 to 6.9 with sodium hydroxide, adding the activated ester and allowing the reaction to proceed for 1 to 5 hours at room temperature. The activated ester used is known and is described, for example, in Japan Kokai 54-95593 (28 07 79] (Hoechst), and in the published German patent application no.

2758000.3 (24 12 77). The use of compounds of formula VIII is described in U.S. Patent No. 4,406,899 (Aburaki et al.).

Other compounds of general formula VIIb can also be acylated in an analogous manner to produce a large number of broad-spectrum cephalosporins.

The invention is illustrated by the following examples, which are not intended to limit the scope of the invention in any way. The signal shapes in NMR spectra are denoted by the following common abbreviations:

s = singlet t = triplet m — multiplet ś = wide signal d = doublet q — quartet dd = double doublet

Example 1 (6R,7R)-trimethylsilyl-7-(trimethylsilyl)amino-3-acetoxymethylcep-3-em-4-carboxylate

Method A

An oven-dried flask equipped with a Friedrich condenser is cooled to room temperature in a stream of dry nitrogen and 50.0 g (184 mmol) of 7-aminocephalosporanic acid of 97.2% purity and 400 ml of 1,1,2-trichlorotrifluoroethane dried over molecular sieves are introduced into it. To the resulting suspension, with vigorous stirring and in the absence of moisture, 46.5 ml (222 mmol; 1.2 equivalents) of 98% 1,1,1,3,3,3-hexamethyldisilazane and 0.80 ml (5.6 mmol; 0.03 equivalents) of iodotrimethylsilane are added. The suspension is heated vigorously to reflux for 16 to 18 hours, after which it is cooled to room temperature. The ^X H-NMR spectrum of a sample of the slightly cloudy reaction mixture indicates greater than 95% conversion to the desired product.

NMR (perdeuterodichloromethane, 360 MHz, á values):

0.23 [s, 9H, N—Si(CH3)3],

0.38 [s, 9H, — COOSi(CH3)3],

1.51 (d, 1H, J = 13.6 Hz, NH—],

2.09 (s, 3H, —COCH3),

3.41 (d, 1H, J == 18.3 Hz, —SCHa—),

3.61 (d, 1H, J = 18 3 Hz, — SCHa),

4.80 [dd, 1H, J = 4.5, 13.6 Hz, —COCH/NHSi(CH3)3/],

4.83 (d, 1H, 1 = 13.2 Hz, —CH2OCOCH3),

4.91 [d, 1H, 1 = 4.5 ^1Hz , —COCH/NHSi(CH3)3CH—/],

5.11 (d, 1H, J = 13.2 Hz, —CH 2 OCOCH 3 ). Method B

An oven-dried flask equipped with a Friedrich condenser is cooled to room temperature in a stream of dry nitrogen and 10.0 g (36.7 mmol) of 7-aminocephalosporanic acid of 97.2% purity and 80 ml of dry 1,1,2-trichlorotrifluoroethane dried over molecular sieves are introduced into it. To the resulting suspension are added 9.3 ml (44.1 mmol; 1.2 equivalents) of 98% 1,1,1,3,3,3-hexamethyldisilazane and 44 ml (1.1 mmol; 0.03 equivalents) of 0.025M hydrogen iodide solution in

1,1,2-trichlorotrifluoroethane (prepared by introducing hydrogen iodide into dry 1,1,2-trichlorotrifluoroethane and titrating the resulting saturated solution with phenolphthalein). The reaction suspension is heated vigorously under reflux for 22 hours with intensive stirring and excluding the access of moisture, after which it is cooled to room temperature. ^X H-NMR spectrum measured in perdeuterodichloromethane at 360 MHz indicates a conversion of more than 95% to the desired product.

Method C

An oven-dried flask equipped with a Friedrich condenser is cooled to room temperature in a stream of dry nitrogen and 10.0 g (36.7 mmol) of 7-aminocephalosporanic acid with a purity of 97.2% and 80 ml of dichloromethane dried over molecular sieves are introduced into it. To the resulting suspension, with vigorous stirring and excluding the access of moisture, 9.3 ml (44.1 mmol; 1.2 equivalents) of 98% 1,1,1,3,3,3-hexamethyldisilazane and 0.16 ml (1.1 mmol; 0.03 equivalents) of trimethylsilyl iodide are added. The reaction suspension is heated vigorously under reflux for 5 hours, after which the slightly cloudy reaction mixture is cooled to room temperature. ^{The X} H-NMR spectrum measured in perdeuterodichloromethane at 360 MHz indicates a conversion of more than 95% to the desired product. Example 2 (6R,7R)-trimethylsilyl-7-(trimethylsilyl)amino-3-iodomethylcep-3-em-4-carboxylate

Method A

To the reaction mixture containing (6R,7R)-trimethylsilyl-7-(trimethylsilyl)amino-3-acetoxymethylceph-3-em-4-carboxylate in 1,1,2-trichlorotrifluoroethane (prepared according to Method A of Example 1 from 50.0 g of 7-aminocephalosporanic acid) under a dry nitrogen atmosphere at room temperature, a total of 30 ml (210 mmol; 1.15 equivalents) of trimethylsilyl iodide was slowly added. The course of the reaction was monitored by ¹ H-NMR spectroscopy (in the acetate region). After one hour, the reaction suspension was filtered under a positive pressure of nitrogen and the solid material was washed once with 100 ml of fresh 1,1,2-trichlorotrifluoroethane. A sample of the filtrate has the following ¹ H-NMR spectrum, which indicates that (6R,7R)-trimethylsilyl-7-(trimethylsilyl)amino-3-iodomethylcep-3-em-4-carboxylate was formed in situ.

NMR (perdeuterodichloromethane, 360 MHz, δ values):

0.16 [s, 9H, NHSi(CH3)3],

0.40 [s, 9H, —COOSi(CH3)3],

1.51 (d, 1H, J = 13.4 Hz, NH),

3.54 (d, 1H, J = 17.9 Hz, —SCHz—),

3.80 (d, 1H, J = 17.9 Hz, —SCH2—),

4.37 (d, 1H, J = 9.2 Hz, —CH2I),

4.49 (d, 1H, J = 9.2 Hz, — CH21),

4.75 [dd, 1H, J = 4.6, 13.4 Hz, —COCH/NHSi[CH3)3/],

4.89 [d, 1H, J = 4.6 Hz, —COCH/NHSi;(iCH3)3/CH—].

Method B

To a stirred solution of (6R,7R)-trimethylsilyl-7-(trimethylsilyl)amino-3-acetoxymethylcef-3-em-4-carboxylate in dichloromethane [prepared according to Method C of Example 1, 20 mL of reaction mixture (11.7 mmol of starting material was used for this reaction)], 1.66 mL (11.7 mmol; 1.0 equivalent) of iodotrimethylsilane was slowly added under nitrogen at room temperature. After stirring for another hour, ^{the 1} H-NMR spectrum (acetate region) of a sample of the reaction mixture indicated greater than 95% conversion to the desired (6R,7R)-trimethylsilyl-7-(trimethylsilyl)amino-3-iodomethylcef-3-em-4-carboxylate.

Example 3 (6R,7R)-7-amino-3-(1-methyl-1-pyrrolidinio)methylceph-3-em-4-carboxylate monohydrochloride

Method A

To a solution of (6R,7R)-trimethylsilyl-7-[trimethylsilyl]amino-3-iodomethylcep-3-em-4-carboxylate in 1,1,2-trichlorotrifluoroethane (prepared according to Method A of Example 2 from 50.0 g of 7-aminocephalosporanic acid) at a temperature of 0 to 5 °C in an atmosphere of dry nitrogen, 19.0 ml (183 mmol; 1.0 equivalent) of 97% N-methylpyrrolidine dried over molecular sieves was added dropwise at a rate such that the temperature of the reaction mixture was maintained below 10 °C. After the addition is complete, the resulting suspension is stirred vigorously for 15 minutes at 0 to 5 °C, then another 100 ml of dry 1,1,2-trichlorotrifluoroethane is added to facilitate stirring, followed by stirring at a rate such that the temperature of the reaction mixture is maintained below 10 °C, and 25 ml (615 mmol; 3.35 equivalents) of methanol are added dropwise. The suspension is then stirred vigorously for another 15 minutes at 0 to 5 °C. The reaction mixture is filtered and the collected solid material is washed once with 100 ml of fresh 1,1,2-trichlorotrifluoroethane. The product is first partially dried by suction for 15 minutes, then dried in vacuo at room temperature for 16 hours. This gives

71.3 g (more than 100%) of crude product.

200 ml of water are added to the material prepared above, the pH of the suspension (2.40) is lowered to 0.50 by dropwise addition of concentrated hydrochloric acid, 10.0 g of activated carbon is added and the resulting suspension is stirred for 15 minutes at room temperature. The activated carbon is filtered through a layer of 10.0 g of diatomaceous earth, which is then washed once with 25 ml of freshly deionized water. The product is precipitated from the aqueous solution by dropwise addition of 5 volumes of acetone. The resulting suspension is cooled to 0 to 5 °C and maintained at this temperature for 30 minutes, after which it is filtered under vacuum. The filter cake is washed successively with 50 ml of cold (0 to 5 °C) acetone and water (5:1) and twice with 50 ml of acetone, partially dried by suction for 15 minutes and then finally dried under vacuum. 23.3 g (39 percent) of snow-white crystalline (6R,7R)-7-amino-3-(1-methyl-1-pyrrolidinio)methylcep-3-em-4-carboxylate monohydrochloride are obtained.

According to high-performance liquid chromatography, the purity of the product is 96.3%.

NMR (deuterium oxide, 360 MHz, delta values):

2.14 — 2.32 [unclear signal shape, 4H, —N(CH3)CH2CH2—],

3.00 (s, 3H, NCH3),

3.46 — 3.67 [m, 5H, —N(CH3),CH2CH2,

SCH2],

3.96 (d, 1H, J = 16.9 Hz, —SCH2),

4.09 (d, 1H, J = 13.9 Hz, =CCH2N—),

4.73 (d, 1H, J = 13.9 Hz, =CCH2N—),

5.21 (d, 1H, J = 5Í.1 Hz, — COCHCHS—),

5.41 (d, 1H, J = 5.1 Hz, —COCHCHS—).

Method B

To a suspension of (6R,7R)-trimethylsilyl-7-(trimethylsilyl)amino-3-(1-methyl-1-pyrrolidino)methylcep-3-em-4-carboxylate iodide in 1,1,2-trichlorotrifluoroethane (prepared according to Method A from 20.0 g of 7-aminocephalosporanic acid), cooled to 0-5°C, 10' ml (246 mmol; 3.35 equivalents) of methanol were added dropwise over 5 minutes under a dry nitrogen atmosphere, while maintaining the temperature below 9°C. After the addition was complete, the suspension was stirred at room temperature for 15 minutes, and then 50 ml of 3N hydrochloric acid (prepared by adding 250 ml of concentrated hydrochloric acid to 756 ml of deionized water) was added dropwise over 10 minutes. After the addition is complete, the cooling bath is removed, the reaction mixture is stirred for 15 minutes, then the phases are separated, the volume of the aqueous phase is adjusted to 100 ml and the aqueous layer is stirred at room temperature for 30 minutes with 4.0 g (20% by weight of the starting 7-aminosporanic acid) of activated carbon. The resulting suspension is filtered through a pad of 4.0 g of diatomaceous earth, which is then washed once with 10 ml of deionized water. The volume of the aqueous filtrate is adjusted to 1Ό0 milliliters.

Crystallization method 1:

To 50 ml of the above-prepared concentrated layer, 250 ml (5 volumes) of acetone are added dropwise to precipitate the product. The resulting suspension is stirred for 1 hour under cooling with ice water, then filtered off with suction, the residue on the filter is washed successively twice with 40 ml of a mixture of acetone and water (5:1) and once with 40 ml of acetone (the washing solutions have a temperature of 0 to 5°C), partially dried by suction for 15 minutes and then dried in vacuum at room temperature (15' hours). 4.48 g (37'%, based on 50% theoretical yield from 20.0 g of the starting 7-aminocephalosporanic acid) of colorless crystalline (6R,7R)-7-amino-3-(1-methyl-1-pyrrolidinyl)methylceph-3-em-4-carboxylate monohydrochloride is obtained. Crystallization method 2:

To 50 ml of the concentrated aqueous layer prepared above, 150 ml (3 volumes) of isopropyl alcohol are added dropwise to precipitate the product. The resulting suspension is stirred for 1 hour under ice-water cooling, then filtered off with suction, the residue on the filter is washed successively twice with 40 ml of a mixture of isopropyl alcohol and water (9:1) and once with 40 ml of acetone (the washing solutions have a temperature of 0 to 5C), partially dried by suction for 15 minutes and then dried in vacuum at room temperature (15 hours). 5.46 g (45%, based on 50% theoretical yield from 20.0 g of the starting 7-aminocephalosporanic acid) of off-white crystalline (6R,7R) -7-amino-3-(1-methyl-1-pyrrolidinio) methylcep-3-em-4-carboxylate monohydrochloride is obtained.

Method C

To a solution of (6R,7R)-trimethylsilyl-7-trimethylsilyl)amino-3-iodomethylcep-3-em-4-carboxylate in dichloromethane (prepared according to Method B of Example 2) at a temperature of 0 to 5 °C in an atmosphere of dry nitrogen, 121 ml (11.7 mmol; 1.0 equivalent) of 97% N-methylpyrrolidine dried over molecular sieves was added dropwise at a rate such that the temperature was maintained below 10 °C. After the addition was complete, the suspension was stirred at a temperature of 0 to 5 °C for 15 minutes, then 0.95 ml (23.5 mmol; 2.0 equivalent) of methanol was added dropwise at a temperature below 10 °C and stirring at a temperature of 0 to 5 °C was continued for another 15 minutes. The solid was filtered off with suction, washed once with 50 ml of methanol and once with 50 ml of dichloromethane and dried in vacuo at room temperature. 2.65 g (76%) of crude ,{6R,7R)-7-amino-3-(1-methyl-pyrrolidinio)methylcep-3-em-4-carboxylate (as hydroiodide) was obtained as a pale red-yellow solid. The ¹ H-NMR spectrum of this material (360 MHz) indicated that the product was a mixture of Δ ² - and Δ ³ -isomers in the ratio 65:35.

Example 4

(6R,7R)-7-Amino-3-{pyridinio)methylcef-3-em-4-carboxylic acid dihydrochloride

To a stirred solution of (6R,7R)-trimethylsilyl-7-(trimethylsilyl)amino-3-iodomethylcep-3-em-4-carboxylate in 1,1,2-trichlorotrifluoroethane (prepared according to Method A of Example 2 from 2.50 g of 7-amyrocephalosporanic acid) at a temperature of 0 to 5 °C in an atmosphere of dry nitrogen, a solution of 1.6 ml (20.0 mmol; 2.2 equivalents) of pyridine dried over potassium hydroxide in 5 ml of 1,1,2-trichlorotrifluoroethane dried over molecular sieves is added dropwise over 10 minutes. After the addition is complete, the reaction mixture is stirred for another 15 minutes, then 1.5 ml (37.0 mmol; 4.0 equivalents) of methanol is added dropwise and the resulting suspension is stirred for 15 minutes at a temperature of 0 to 5 °C. The solid was filtered off with suction, washed with fresh 1,1,2-trichlorotrifluoromethane and dried in vacuo to constant weight to give 3.0 g of crude product.

The presence of the desired (6R,7R)-7-amino-3-(pyridinium)methylcef-3-em-4-carboxylate (as hydroiodide) in this crude material was confirmed by comparison of ^{the 1} H-NMR spectrum (360 MHz) and chromatogram obtained by high-performance liquid chromatography (purity 34%) with the spectrum and chromatogram of an authentic sample of this material prepared independently [see also GCD Smith, European Patent Application No. 70706, 26 01 83, p. 21].

Example 5

An attempt to prepare (6R,7R)-7-amino-3-,(1-methyl-1-pyrrolidinio) methylcef-3-em-4-carboxylate monohydrochloride by the sequential reaction of (6R,7R)-trimethylsilyl-7-(trimethylsilyl)amino-3-acetoxymethylcef-3-em-4-carboxylate in

1,1,2-trichlorotrifluoroethane with chromotrimethylsilane, N-methylpyrrolidine and aqueous hydrochloric acid solution

To a slightly cloudy reaction mixture containing (6R,7R)-trimethylsilyl-7-(trimethylsilyl)amino-3-acetoxymethylcep-3-em-4-carboxylate in 1,1,2-trichlorotrifluoroethane (prepared according to Method A of Example 1 from 10.0 g of 7-aminocephalosporanic acid) was slowly added over 1 minute with stirring at room temperature under a dry nitrogen atmosphere.

4.3 ml (42.2 mmol; 1.15 equivalents) of 98% bromotrimethylsilane. The reaction was monitored by ¹ H-NMR spectroscopy. After stirring for 90 minutes at room temperature, only traces of the reaction products (3-bromomethylcephalosporin and trimethylsilyl acetate) could be detected in the reaction mixture. The reaction mixture was heated gently to reflux under nitrogen and the reaction was monitored by ^X H-NMR spectroscopy. After 10 days, the starting materials predominated in the reaction mixture. When the reaction mixture was analyzed by ^X H-NMR spectroscopy (360 MHz), only 15% (based on the signal area) of conversion to the desired (6R,7R)-trimethylsilyl-7-(trimethylsilyl)amino-3-bromomethylcep-3-em-4-carboxylate was detected at best.

Example 6

Attempt to prepare (6R,7R)-7-amino-3-(1-methyl-1-pyrrolidinio)methylcef-3-em-4-carboxylate monohydrochloride by the sequential reaction of (6R,7R)-trimethylsilyl-7-(trimethylsilyl)amino-3-acetoxymethylcef-3-em-4-carboxylate in

1,1,2-trichlorotrifluoroethane with chlorotrimethylsilane, N-methylpyrrolidine and aqueous hydrochloric acid solution

This experiment was carried out as described in Example 5, except that 5.4 ml (42.2 mmol; 1.15 equivalents) of chlorotrimethylsilane was used instead of bromotrimethylsilane. After heating the reaction mixture under reflux for 10 days under nitrogen, ^X H-NMR spectroscopy (360 MHz) indicated the presence of predominantly chlorotrimethylsilane and (6R,7R)trimethylsilyl-7-(trimethylsilyl)amino-3-acetoxymethylcep-3-em-4-carboxylate.

At most 5% (based on signal area) conversion to the desired (6R,7R)-trimethylsilyl-7-(trimethylsilyl)amino-3-chloromethylcep-3-em-4-carboxylate was detected.

Example 7

Reaction scheme for the preparation of (6R,7R)-7-amino-3-(1-methyl-1-pyrrolidinio)methylcep-3-em-4-carboxylate hydrochloride or hydroiodide in one reaction vessel, i.e. without isolation of intermediates

The following section provides an overview of the experiences and observations obtained when repeating the reactions several times using the same amounts of reactants, reaction temperatures, etc.

Procedure

1.

50.0 g (0.184 mol) of 7-aminocephalosporanic acid (Note 1) is introduced into 350 ml of 1,1,2-trichlorotrifluoroethane under a nitrogen atmosphere.

2.

To the suspension prepared above, 46.5 ml (0.22 mol; 1.2 equivalents) of 1,1,1,3,3,3-hexamethyldisilazane are added in a single portion with stirring.

3.

To the mixture was added 0.78 mL (6.0 mmol; 0.03 equivalents) of trimethylsilyl iodide (Note 2) in a single dose using a syringe.

4.

The reaction mixture is heated to reflux for 7 to 10 hours [Notes 3 and 4], while the reaction is monitored by NMR spectroscopy (Note 5).

The silylation mixture was cooled to room temperature, diluted with 150 ml of 1,1,2-trichlorotrifluoroethane and cooled to 5°C under a nitrogen atmosphere.

6.

26.83 ml (0.26 mol; 1.4 equivalents) of N-methylpyrrolidine are added over 10 minutes with vigorous stirring, maintaining the reaction temperature below 10°C (Note 6).

7.

To the mixture from reaction step 6, at 5°C and with vigorous stirring, 47.1 mil (0.33 mole; 1.8 equivalents) of trimethylsilyl iodide is slowly added via syringe over 10 to 15 minutes.

A slight exothermic reaction occurs during the addition of trimethylsilyl iodide. The reaction suspension is stirred at 5 °C under a dry nitrogen atmosphere for 30 minutes.

8.

The resulting suspension is carefully heated to 35-36°C and stirred at this temperature for 45-55 hours. The course of the substitution reaction is monitored by high-performance liquid chromatography (Note 7).

9.

Both the volume of the reaction mixture and the stirring rate are checked regularly. An additional 100 ml of 1,1,2-trichlorotrifluoroethane (Note 8) is added as necessary.

10.

After the reaction is complete (in the HPLC chromatogram the area corresponding to 7-aminocephalosporanic acid is less than 2% of the total area), the resulting suspension is cooled to 5 °C under nitrogen and 25 ml (0.615 mol) of methanol (Note 9) is added dropwise over 8 minutes at 5 °C.

11.

After the addition of methanol, after which the suspension becomes considerably diluted, the mixture is stirred for another 15 minutes at a temperature of 5 to 10 °C.

12.

The cooling bath is removed and 125 ml of 3N hydrochloric acid, prepared by adding 250 ml of concentrated hydrochloric acid to 756 ml of water, is added to the mixture over a period of 2 minutes with vigorous stirring. During this addition, the temperature of the reaction mixture rises to 12-15°C.

13.

The mixture in which hydrolysis is taking place is heated as quickly as possible to 20 to 25 °C (but not above 25 °C) and stirred for 15 minutes at 20 to 25 °C.

14.

The phases are separated and the organic phase (lower phase) is extracted once with 50 ml of water. This aqueous phase is used as a wash when filtering the separated aqueous solution.

15.

To the separated aqueous solution from step 14, 2.5 g of diatomaceous earth was added and the mixture was filtered through a pad of 7.5 g of diatomaceous earth. The diatomaceous earth pad was washed with the aqueous phase obtained from the extraction of the organic phase in step 14 and then with 25 ml of deionized water.

16.

The aqueous phase is combined with the washings and the resulting solution, approximately 270 milliliters in volume, which is reddish brown, is stirred for 30 minutes at a temperature of 21 to 23 °C with 10 g of activated carbon. After adding 2.5 g of diatomaceous earth, the mixture is stirred for a further 5 minutes.

17.

The activated carbon is filtered off through a layer of 7.5 g of diatomaceous earth, the filter cake is washed once with 75 ml of water and dried for 5 minutes by suction.

18.

If necessary, separate any residues

of 1,1,2-trichlorotrifluoroethane deposited under an aqueous solution.

19.

Isopropyl alcohol is added dropwise to a clear, orange-colored aqueous solution with a volume of approximately 350 ml and a pH of 0.9 to 1.15 until turbidity begins to appear (Note 10).

20.

The addition of isopropyl alcohol was stopped and the mixture was allowed to crystallize for 15 minutes at 21-23°C.

21.

After this time, additional isopropyl alcohol is added to the suspension over 45 to 60 minutes (a total of 1.2 liters of isopropyl alcohol is added) and the resulting suspension is stirred for 60 minutes while cooling to 0 to 5°C.

22.

The product is filtered off and the filter cake is washed with a cold (0 to 5°C) isopropyl alcohol:water mixture 9:1 (twice 100 ml; Note 11) and once 100 ml acetone. The product (Note 12) is dried by suction for 15 minutes and then dried in vacuo to constant weight. This gives 46 to 51 g (75 to 83%) of the crude mixture of hydrochloride and hydroiodide of the title compound (compound of general formula I) as an off-white to white crystalline solid. The yield (calculated on the basis of the activity) is 60 to 63.4 percent.

23.

According to NMR spectroscopy, the product has a purity of more than 95%. The ratio determined by high-performance liquid chromatography compared to the analytical formula 4 ³ -form of the hydrochloride of the compound of formula I is 750 to 800 /zg/mg. The purity calculated from the signal area is more than 95 percent.

Note 1:

7-Aminocephalosporanic acid is an extremely dusty solid that should be weighed out in a fume hood or other location with adequate ventilation. Respirators and, if necessary, appropriate protective clothing or equipment should be used to protect against dust particles of 7-aminocephalosporanic acid.

Note 2:

All operations with trimethylsilyl iodide should be carried out with the greatest possible exclusion of moisture.

Note 3:

The reaction time was found to vary and is likely dependent on the presence of trimethylsilyl iodide or its reactive equivalent as a catalyst. If the reaction is slow, the addition of more trimethylsilyl iodide will accelerate and complete it.

Note 4:

It is important to maintain a vigorous reflux, as the main driving force of the reaction is the removal of the ammonia produced.

Note 5:

It is important to work under anhydrous conditions when sampling the reaction mixture, which applies to all reactions in this procedure. Note 6:

An increase in temperature above 10°C during the addition of N-methylpyrrolidine results in the formation of a higher amount of the undesired A ² -isomer (in a ratio of 1:26).

Note 7:

Samples should be analyzed by high-performance liquid chromatography every 4 to 6 hours. The reaction temperature, reaction time, concentration and number of equivalents of trimethylsilyl iodide, as well as the alkalinity of the reaction medium play a decisive role in this reaction.

Note 8:

The suspension becomes very thick and to facilitate mixing, the mixture must be diluted with a certain amount of 1,1,2-trichlorotrifluoroethane.

Note 9:

Before the methanol is added, the suspension is so thick that clumps of material stick to the walls of the reaction vessel, making it difficult to mix thoroughly with the methanol. It is necessary to observe and check that good and complete mixing occurs in all areas of the reaction vessel.

Note 10:

Typically 0.5 to 1.0 volume of isopropanol is required.

Note 11.

The washing liquid is prepared by mixing 90 ml of isopropanol and 10 ml of water and cooling the mixture in ice water to 0 to 5 ^° C.

Note 12:

In a separate experiment, the product is isolated as pure hydroiodide by treating the suspension from reaction step 11 with 125 ml of 3N hydrogen iodide instead of 125 ml of 3N hydrogen chloride (as in step 12). The above-described work-up (see steps 13 to 21) of the aqueous phase yields 44.3 g of white crystalline hydroiodide. The corrected HPLC efficiency against the analytical hydrochloride standard is 105%. The yield based on 7-aminocephalosporanic acid (calculated on efficiency) is 56.7%.

Example 8

Recrystallization of (6R,7R)-7-amino-3-(1-methyl-1-pyrrolidinio)methylcep-3-em-4-carboxylate monohydrochloride (hydrochloride of general formula I)

PROCEDURE

1.

To 125 ml (3.5 mol; 3.50 equivalents) of 1N hydrochloric acid is added, with vigorous stirring, in a single portion, 15.0 g (0.045 mol) of the crude hydrochloride of general formula I (Note 1, 2).

2.

The resulting mixture was stirred at room temperature for 5 minutes.

3.

In a single dose, 8.0 g of activated carbon is added with vigorous stirring and the suspension is stirred for a further 45 minutes,

8 2 S 9 δ

4.

The suspension is filtered through a pad of 8.0 g of diatomaceous earth, the filter cake is washed once with 35 ml of water and dried by suction for 5 minutes.

5.

The slightly cloudy filtrate is clarified through a 5 μm pore size filter, yielding a sparklingly clear aqueous filtrate of 170 ml.

6.

Isopropyl alcohol (125 ml) is added dropwise over 25 minutes with vigorous stirring until turbidity begins to appear, after which the addition of isopropanol is stopped.

The resulting suspension is stirred for 1.5 minutes at room temperature, during which time crystal nuclei develop well.

7.

Over a period of 25 minutes, another 475 ml of isopropyl alcohol (Note 3) is added dropwise with vigorous stirring.

8.

The resulting suspension was stirred for 1 hour under ice-water cooling.

9.

The suspension is filtered and washed successively at 0 to 5 °C twice with 120 ml of a mixture of Isopropanol and water in a ratio of 9:1 (Note 4) and once with 120 ml of acetone, analysis calculated

10.

The filter cake is partially dried by suction for 15 minutes. Further drying in a vacuum of a steam pump at a temperature of 40°C for 15 hours gives 7.87 g (52%) of snow-white electrostatic crystalline hydrochloride of formula I (Note 5).

Note 1:

The number of moles of the starting hydrochloride of formula I is based on 100% purity.

Note 2:

IN hydrochloric acid solution is prepared by adding 83 ml of concentrated hydrochloric acid to 920 ml of distilled water.

Note 3:

The total volume of isopropyl alcohol used for crystallization is Θ00 ml, which is 3.5 times the volume of the clarified aqueous filtrate from step 5.

Note 4:

The isopropyl alcohol/water wash mixture, consisting of 108 ml of isopropyl alcohol and 12 ml of water, is cooled in ice to 0 to 5 °C. Note 5:

The following section presents the analytical data of the recrystallized hydrochloride of formula I:

found corrected to KF % C % H % N % S KF (H2) residue (sulfate ash]

The efficiency in high-performance liquid chromatography is 99.5% compared to the standard sample of the hydrochloride of formula I. Klett number — 3 (a sample weighing 100.0 mg is diluted in a volumetric flask with purified water [Milli-Q] to a volume of 10 ml and the solution is filtered through a special filter for high-performance liquid chromatography [Millex]; cold light; path length 1.2 cmj.

It has generally been found that the “crude” hydrochloride of formula I, obtained by adding hydrogen chloride to the final mixture, contains a certain amount of hydroiodide of formula I, which is formed from the iodide present in the intermediate of formula II. Therefore, despite its high antibacterial purity, this product must be normalized.

46.77 46.02 46.71 6.04 6.17 6.10 12.59 12.31 12.49 9.61 9.50 9.64 — 1.47

<0.1 molar recrystallize as described above to remove the hydroiodide of formula I.

In contrast, the hydroiodide of formula I, prepared by adding hydrogen iodide to the final reaction mixture, does not contain the hydrochloride of formula I after primary crystallization. Accordingly, the hydroiodide of formula I is normally highly pure and does not require recrystallization.

Example 9

Conversion of a compound of general formula I (X = HCl) to a compound of formula VIII

6 2 6 9 S

21.72 g (0.0612 mol) of a compound of the general formula I, in which X represents hydrogen chloride, are dissolved in 190 ml of water at 25 °C with stirring. The mixture is cooled to 8-10 °C and its pH is adjusted from 2.5 to 5.8 (range 5.7-5.9) by dropwise addition of 30.5 ml (0.061 mol; 1.0 equivalent) of 2N sodium hydroxide solution. The total volume of the mixture is 214 ml.

555 ml of tetrahydrofuran are added in three portions. After the addition of each of these portions, the temperature of the mixture rises to 12 to 13 °C and before the addition of the next portion it is always reduced again to 8 to 10 °C. The addition takes a total of 10 minutes, the pH of the reaction mixture is 5.8 to 6.1.

The pH of the mixture was adjusted to 6.8 (range 6.7 to 6.9) by dropwise addition of 2.0 ml (0.004 mol) of 2N sodium hydroxide solution.

A total of 29.5 g (0.0927 mol) of the activated ester [1-benzotriazole-(Z)-2-(2-aminothiazol-4-yl)-2-methoxyiminoacetate] is added to the mixture in 5 equal portions over 45 minutes. After the addition of the first portion of the activated ester, the cooling bath is removed and before each subsequent portion of the activated ester is added, the pH of the reaction mixture is readjusted to 6.5 (range 6.5 to 6.7) by dropwise addition of 2N sodium hydroxide solution.

The clear, light orange reaction mixture was stirred at 25°C for 2 to 3 hours, with the pH being adjusted to 6.5 (range 6.5 to 6.7) every 5 to 10 minutes during the first 30 minutes by adding 2N sodium hydroxide solution. The pH was adjusted to 6.5 every 15 minutes for the remainder of the reaction time. A total of 29.5 ml of 2N sodium hydroxide (0.059 mol; 0.97 equivalent) was used. The completion of the reaction was confirmed by high-performance liquid chromatography.

The solids are filtered off from the reaction mixture and washed twice with 5 ml of water each time. The filtrate is extracted with 790 ml of methyl isobutyl ketone and the aqueous layer is separated. The organic phase is washed with 64 ml of water, the aqueous phases are combined and stirred for 10 minutes with 5.1 g of Dicalite. The solids are filtered off with suction and washed twice with 5 ml of water each time.

The resulting clear orange solution (314 ml) was acidified with vigorous stirring by adding 14.5 ml of 4N sulfuric acid dropwise to pH 3.7 (range 3.5 to 4.0). After this acidification, the mixture became cloudy and the sulfuric acid addition salt of the compound of formula VIII began to crystallize.

Crystallization is allowed to proceed for 10 to 15 minutes, after which the pH is adjusted to 3.0 (range 2.9 to 3.1) by dropwise addition of 7.5 ml of 4N sulfuric acid. The mixture is cooled to 0 to 5 °C and a further 63.5 ml of 4N sulfuric acid is added over 20 to 30 minutes, so that the resulting mixture has a pH of 1.3 to 1.5. After the addition of sulfuric acid is complete, the suspension is stirred for 1 hour at a temperature of 0 to 5 °C.

The white crystalline product is filtered off with suction and washed with 63.5 ml of 0.5N sulphuric acid. The solids are filtered off with suction, partially dried by suction for 15 minutes, washed twice with 100 ml of acetone each time, partially dried again by suction for 10 minutes and then stirred vigorously in 400 ml of acetone for 1 hour. The solid material is filtered off with suction, washed twice with 100 ml of acetone each time and dried under a vacuum of 1,333 to 2,000 Pa at a temperature of 35 to 40 °C to constant weight (3 to 6 hours).

The product, which is the sulfuric acid addition salt of the compound of formula VIII, is isolated as a slightly electrostatic white crystalline solid.

The yield is 28.79 g (81.4%).

Example 10

Conversion of a compound of general formula I (X HI) to a compound of formula VIII

The general procedure described in the previous example is repeated, except that an equimolar amount of the hydroiodide of formula I is used instead of the hydrochloride of formula I. The title compound is obtained.

Further details of the process according to the invention are illustrated by the following examples. In the formulas given in these examples, the abbreviation Ac represents an acetyl group and the abbreviation IMS represents a trimethylsilyl group.

Example 11 (6R,7R)-trimethylsilyl-7-(trimethylsilyl)amino-3-acetoxymethylcep-3-em-4-carboxylate (f

H

TNS N.

and

CQ-H

2.

c >.....

CO,TMS

An oven-dried flask equipped with a reflux condenser is cooled to room temperature in a stream of nitrogen, after which 10.0 g (36.7 mmol) of 7-aminocephalosporanic acid with a purity of 97.2% and 70 ml of 1,1,2-trichlorotrifluoroethane dried over molecular sieves are introduced into it. To the resulting suspension, with vigorous stirring and excluding moisture, 9.3 ml (44.1 mmol; 1.2 equivalents) of 98% 1,1,1,3,3,3-hexamethyldisilazane and 0.16 ml (1.1 mmol; 0.03 equivalents) of iodotrimethylsilane are added using a syringe. The suspension is heated vigorously under reflux for 7 to 10 hours with a gentle introduction of nitrogen, then cooled to room temperature in an atmosphere of dry nitrogen and diluted with 30 ml of of fresh 1,1,2-trichlorotrifluoroethane. The ¹ H-NMR spectrum of a sample of the slightly cloudy reaction mixture indicates greater than 95% conversion to the desired product, which is identical to the product from Example 1. ^{The 1} H-NMR spectrum of the product is identical to the spectrum of the product reported in Method A of Example 1.

Example 12 (6R,7R)-7-amino-3-(1,-methyl-1-pyrrolidinio)methylcep-3-em-4-carboxylate monohydro iodide

To a slightly cloudy solution of (6R,7R)-trimethylsilyl-7 (trimethylsilyl) amino-3-acetoxymethylcef-3-em-4-carboxylate in 1,1,2-trichlorotrifluoroethane (prepared according to the procedure of Example 11) is added dropwise over 1 to 2 minutes with vigorous stirring at a temperature of 0 to 5 °C in an atmosphere of dry nitrogen, '5.35 ml (51.4 mmol; 1.4 equivalents] of 97% N-methylpyrrolidine dried over molecular sieves, after which 9.40 ml (66.1 mmol; 1.8 equivalents) of trimethylsilyl iodide are added via syringe over 5 minutes with continuous vigorous stirring. During the addition, the reaction temperature is maintained below 10 °C. The resulting suspension is stirred for another 30 minutes at a temperature of 0 to 5 °C and then placed in an oil bath, the The temperature is carefully maintained at 35 to 36 °C. The reaction is monitored by high-resolution liquid chromatography. After 45 to 48 hours, the reaction is complete (the 7-aminocephalosporanic acid content is less than 2% of the signal area). The reaction mixture is cooled to 0 to 5 °C under dry nitrogen and a total of 5.0 ml (123 mmol; 3.35 equivalents) of methanol are added dropwise with vigorous stirring, the temperature being maintained below 10 °C during this addition. The suspension is stirred for a further 15 minutes at 0 to 5 degrees Celsius, after which 25 ml of 3N aqueous hydrogen iodide solution (75 mmol; 2.0 equivalents) are added in a single portion. After the addition is complete, the cooling bath is removed and the two-phase mixture is rapidly warmed to 20 to 25 °C, at which temperature it is further stirred. Stir vigorously for 15 minutes. The phases are separated and the organic phase is extracted once more with 10 ml of water. This aqueous extract is saved for later use.

The main aqueous phase is stirred with 0.5 g of diatomaceous earth at a temperature of 20 to 25 degrees Celsius for 10 minutes. The suspension is filtered through a layer of 1.5 g of diatomaceous earth previously washed with 50 ml of water, after filtration the diatomaceous earth layer is washed first with the aqueous extract obtained above and then once with 5 ml of water. The filter cake is partially dried by suction for 5 minutes. After adding 2.0 g of activated carbon to the filtrate, the suspension is stirred for 30 minutes at a temperature of 20 to 25 °C, after which 0.5 g of diatomaceous earth is added to it and stirring is continued for another 5 minutes. The resulting suspension is filtered through 1.5 g of diatomaceous earth previously washed with 50 ml of water and after filtration this layer is washed once with 5 ml of water, after which it is partially dried by suction for 5 minutes. The filtrate is clarified by filtration through a filter with a pore size of 5 μη.

To the clear, amber-colored aqueous phase, 3.5 volumes of isopropanol are added dropwise at 20 to 25 °C to precipitate the product. The resulting suspension is cooled to 0 to 5 °C, left to stand for 1 hour, filtered, and the filter residue is washed at 0 to 5 °C, first twice with 20 ml of a mixture of isopropanol and water (4:1 volume/volume) and then twice with 20 ml of acetone. The filter cake is first partially dried by suction for 5 minutes and then dried in vacuo at 20 to 25 degrees Celsius to constant weight. 8.94 g (57%) of white crystalline (6R,7R)-7-amino-3-(1-methyl-1-pyrrolidinio)methylcep-3-em-4-carboxylate monohydroiodide are obtained. According to high-performance liquid chromatography, the purity of the salt is 97% (based on area) and ^{the X} H-NMR spectrum (360 MHz) of the monohydroiodide of the title compound is identical to ^{the X} H-NMR spectrum of the hydrochloride of the corresponding product prepared according to method A of Example 3.

Example 13 (6R,7R)-7-amino-3-(4-methyl-4-morpholino)methylcep-3-em-4-carboxylate monohydro iodide

H

Tí/iSir (ý __ /,5,.

..... ^CA ^ ______'· cor Cí

262S98

The title compound was prepared from a solution of (6R,7R)-trimethylsilyl-7-(trimethylsilyl]amino-3-cethoxymethylcep-3-em-4-carboxylate in 1,1,2-trichlorotrifluoroethane (from 50.0 g of starting 7-aminocephalosporanic acid) by the procedure described in Example 12, except that instead of N-methylpyrrolidine, 28.3 ml (257 mmol; 1.4 equivalents) of N-methylmorpholine dried over molecular sieves was used. The reaction was monitored by high-resolution liquid chromatography. At a temperature of 35-36 °C, the reaction was complete in 7-8 hours. The reaction mixture was worked up by the procedure described in Example 12 (due to the increased amount of starting material, the amounts of all materials used were multiplied fivefold) to give 36.0 g (41%] of slightly dirty white crystalline monohydroiodide (6R,7R)-7-amino-3-(4-methylmorpholinio)methylcep-3-em-4-carboxylate. According to high-performance liquid chromatography, the purity of the product (calculated on an area basis) is greater than 95%.

¹ H-NMR (deuterium oxide, 360 MHz, δ values):

calculated:

35.40% C, 4.34% H, 9.53% N, found:

34.99% C, 4.38% H, 9.35% N. Example 14 (6R,7R)-7-amino-3-(1-pyridinio)methylcep-3-em-4-carboxylate monohydroiodide

H

TMS M

0'

What is it?

\.

OAc cojhs

3.30 (s, 3H, N—CH 3 ),

3.60 [m, 4H, —N(CH3)CHzCH2OCH2CH2],

3.68 (d, lil, J ···: 10 Hz, - -SCIHl.

4.04 (d, 1H, J= 10 Hz, — AIM·—),

4.2 [m, 4H, —N(CH3)'CH2CH2OCH2CH2],

4.25 (d, 1H, ) - 14 Hz,

In >

-• ^C +V/ ^ch j

4.93 (d, 1Η, J = 14 Hz,

5.30 (d, 1H, J = 5 Hz,

C-6 /β-lactam),

5.53 (d, 1H, J = 5 Hz, C-7 (S-lactam). IR (KBr technique):

460, 1,795 and 1,600 cnv ¹ .

Analysis for: C13H19N3O4S . H1

The title compound was prepared from a solution of (6R,7R)-trimethylsilyl-7-(trimethylsilyl)amino-3-acetoxymethylceph-3-em-4-carboxylate in 1,1,2-trichlorotrifluoroethane (from 10.0 g of the starting 7-aminocephalosporanic acid) by the procedure described in Example 12, except that instead of N-methylpyrrolidine, 4.2 ml (51.4 mol; 1.4-equivalent) of pyridine dried over potassium hydroxide was used. The course of the reaction was monitored by high-resolution liquid chromatography. At a temperature of 35-36 °C, the reaction was complete in 51 hours. The resulting suspension was filtered under nitrogen pressure and the filter residue was washed twice with 100 ml of fresh 1,1,2-trichlorotrifluoroethane. The filter cake is quickly added to 50 ml of dry dichloromethane precooled in ice-water to 0-5 °C and 5.0 ml (123 mmol; 3.35 equivalents) of methanol are added dropwise to the resulting dark solution with vigorous stirring at a temperature below 10 °C. The resulting suspension is stirred for a further 15 minutes at a temperature of 0-5 °C, then the solid is filtered off and washed twice with 50 ml of fresh dichloromethane. The filter cake is suspended in 150 ml of dichloromethane, the suspension is stirred for 1 hour, then the solid product is filtered off and, after washing twice with 50 ml of dichloromethane, it is dried in vacuo at 20-25 °C to constant weight. 14.7 g (95%) of crude (6R,7R)-7-amino-3-(1-pyridinio)methylcep-3-em-4-carboxylate monohydroiodide are obtained.

The 1H-NMR spectrum, measured at 360 MHz, and the chromatogram obtained by high-resolution liquid chromatography of the material obtained above (purity 65% — calculated by area; the main impurity is pyridine hydroiodide, the amount of which is 13% by area) correspond to the spectrum and chromatogram of an authentic sample prepared independently (see also G. C. D. Smith, European Patent Application No. 70706, 26 January 1983, p. 21).

Example 15 [6R,7R]-7-amino[1-(2,3-cyclopenteno)pyridinio]methylcep-3-em-4-carboxylate monohydroiodide

H

T/S ;M

O'

-....../ c

.....

cr

O

The title compound was prepared from a solution of (6R,7R)-trimethylsilyl-7-(trimethylsilyl)amino-3-acetoxymethylceph-3-em-4-carboxylate in 1,1,2-trichlorotrifluoroetham (from 10.0 g of starting 7-aminocephalosporanic acid) by the procedure of Example 12, except that instead of N-methylpyrrolidine, 6.02 ml (51.4 mmol; 1.4 equivalents) of 2,3-cyclopentenopyridine dried over molecular sieves were used. The reaction was monitored by high-performance liquid chromatography. At a temperature of 35-36 °C, the reaction was complete in 52 hours. Working up the reaction mixture using the procedure described in Example 14 gave 13.2 g (78%) of crude (6R,7R)-7-amino-3-(1-(2,3-cyclopenteno)pyridinio]methylcep-3-em-4-carboxylate monohydro iodide.

The 11-NMR spectrum of this material, measured at 360 MHz, and the chromatogram obtained by high-performance liquid chromatography (purity 92% — calculated from the area) correspond to the spectrum and chromatogram of an authentic sample of this product, prepared independently.

Example 16 (6R,7R)-7-amino-3-11-(2-acetoxy)ethyl-1-pyrrolidiniomethylcep-3-em-4-carboxylate monohydro iodide

The title compound was prepared from a solution of (6R,7R)-trimethylsilyl-7-(trimethylsilyl)amino-3-acetoxymethylcep-3-em-4-carboxylate in 1,1,2-trichlorotrifluoroethane (from 10.0 g of starting 7-aminocephalosporanic acid) by the procedure described in Example 12, except that 8.08 g (51.4 mmol; 1.4 equivalents) of N-(2-acetoxy)ethylpyrrolidine were used instead of N-methylpyrazolidine. The reaction was monitored by high-performance liquid chromatography. During the first 22 hours, when the reaction was carried out at 35-36 °C, an oil separated from the reaction mixture. After a total of 48 hours (at 35-36 °C), no further consumption of starting material occurred. The reaction mixture was cooled to 0 °C under dry nitrogen. to 5 °C and while maintaining the temperature below 10 °C, a solution of 7.45 ml (184 mmol; 5.0 equivalents) of methanol in 50 ml of 1,1,2-trichlorotrifluoroethane is added dropwise. After the addition is complete, the resulting suspension is first stirred for 3.5 hours at a temperature of 0 to 5! °C, then filtered off with suction, the filter cake is washed twice with 50 ml of 1,1,2-trichlorotrifluoroethane each time and dried in vacuo at a temperature of 20 to 25 °C to constant weight. 27.9 g (more than 100%) of crude product is obtained.

The presence of the desired (6R,7R)-7-amino-3[1-(2-acetoxy)ethyl-1-pyrrolidinio]methylceph-3-em-4-carboxylate monohydroiodide in this crude material is verified by comparing ^{the 4} H-NMR spectrum (360 MHz) of this material and its chromatogram obtained by high-resolution liquid chromatography with the spectrum and chromatogram of authentic material prepared by an independent procedure. According to ^{the 1} H-NMR spectrum (360 MHz), the product contains the A ³ -isomer and the A ² -isomer in a ratio of 1 : 1.7 and a significant amount of the starting amine. In the chromatogram, the A ³ -isomer occupies 24% of the area and the undesired A ² -isomer is present in an amount corresponding to 34% of the area.

Example 17 (6R,7R)-7-amino-3-[1-(2-trimethylsilyloxy)ethyl-1-pyrrolidinium]-methylcep-3-em-4-carboxylate monohydroiodide

The title compound was prepared from a solution of (6R,7R)-trimethylsilyl-7-(trimethylsilyl)amino-3-acetoxymethyl cephalosporin-4-carboxylate in 1,1,2-trichlorotrifluoroethane (from 10.0 g of starting 7-aminocephalosporin acid) by the procedure described in Example 12, except that 9.63 g (51.4 mmol; 1.4 equivalents) of N-(2-trimethylsilyloxy)ethylpyrrolidine were used instead of N-methylpyrrolidine. The course of the reaction was monitored by high-resolution liquid chromatography. The resulting mixture of A ³ - and A ² -isomers of the title compound was detected as a mixture of the corresponding free hydroxy compounds, due to hydrolysis of the trimethylsilyl residue during chromatography. During the first 23 hours, during which the temperature was 35 to 36 °C, an oily material precipitates from the reaction mixture. After a total of 30 hours of reaction at 35-36 °C, no more starting material is consumed. By working up the reaction mixture in exactly the same way as in Example 16, 29.77 g (more than 100%) of crude product is obtained.

The presence of the desired (6R,7R)-7-amino-3-(1-(2-trimethylsilyloxy)ethyl-1-pyrrolidinio]methylcep-3-em-4-carboxylate monohydroiodide in this crude material is verified by comparing ^{the 1} H-NMR spectrum (360 MHz) of this material and its chromatogram obtained by high-resolution liquid chromatography with the spectrum and chromatogram of the authentic material prepared independently. According to ^{the 1} H-NMR spectrum (360 MHz), the product contains the A ³ -isomer and the A ² -isomer in a ratio of 1:3.3 and a significant amount of the starting amine. In the chromatogram, the desired A ³ -isomer occupies 16% of the area and the A ² -isomer is present in an amount corresponding to 60% of the area.

Example 18

7-[α-(2-aminothiazol-4-yl)-α-(Z)-methoxy iminoacetamido)-3-((1-methyl-1-pyrrolidinio)methyl]-3-cephem 4-carboxylate ί-

Ο ^! 3 ...........x, i

CO£ _CH3

In 87 ml of water, 12.76 g (30 ^mmol ) of (6R,7R)-7-amino-3-(1-methyl-1-pyrrolidinio)methylcep-3-em-4-carboxylate monohydro iodide (prepared in Example 12) are suspended at a temperature of 20 to 25 C C with vigorous stirring, the suspension is cooled to 8 to 10 °C and its pH is increased to 5.80 at a temperature of 7 °C by dropwise addition of 13.0 ml of 2N sodium hydroxide solution (26 mmol; 0.87 equivalent) within 35 minutes. After addition of 555 ml of tetrahydrofuran, the pH of the resulting solution is increased to 6.8 at 10 °C by dropwise addition of 1.9 ml of 2N sodium hydroxide solution (3.8 mmol; 0.13 equivalent). The cooling bath is removed and the mixture is added in two equal portions by weight 14.75 g 29.5 g (92.7 mmol; 1.5 equivalents) of activated hydroxybenzotriazolyl ester of syn-2-i(2-aminothiazol-4-yl)-2-methoxyiminoacetic acid are added every 30 minutes. After each addition, the pH is adjusted to 6.5 again by adding 2N sodium hydroxide solution dropwise every 5 to 10 minutes. During the remaining reaction time, the pH is adjusted to 6.5 again by adding 2N sodium hydroxide solution dropwise every 15 minutes. A total of 28.6 ml of 2N sodium hydroxide (57.2 mmol; 1.91 equivalents) are consumed. The end of the reaction is determined by high-performance liquid chromatography.

After 1.75 hours, the resulting dark solution is poured into 365 ml of methyl isobutyl ketone, the lower aqueous phase is separated and the organic phase is extracted once more with 30 ml of water. The combined aqueous phases are stirred for 10 minutes at 20-25 °C and 2.35 g of diatomaceous earth, the insoluble material is filtered off with suction and the filter cake is washed once with 5 ml of water. The amber-colored aqueous phase is clarified by filtration through a filter with a pore size of 5 µm. At 17 °C, the solution has a pH of 6.40.

To this solution is added 6.7 ml of 4N sulfuric acid with vigorous stirring, resulting in a cloudy solution having a pH of 3.82 at 18 °C. The product is allowed to crystallize from this solution with vigorous stirring for 5 minutes, after which a further 3.5 ml of 4N sulfuric acid is added. The resulting suspension, which has a pH of 3.09 at 20 °C, is cooled to 0 to 5 °C and 30 ml of 4N sulfuric acid are added dropwise over 20 minutes. The mixture is stirred at 0 to 5 °C for 1 hour, then the precipitate formed is filtered off and washed once with 30 ml of 0.5N sulfuric acid. The filter cake is partially dried by suction for 15 minutes, then washed twice with 50 ml of acetone, partially dried again with suction for 15 minutes, and then stirred for 1 hour in 200 ml of acetone at 20-25°C. The salt is filtered off, washed twice with 50 ml of acetone, partially dried by suction for 15 minutes, and then dried in vacuo at 40°C to constant weight. 12.41 g (72%) of the crystalline, slightly off-white title compound is obtained as the sulfuric acid salt.

¹ H NMR (deuterium oxide, 360 MHz, delta values):

2.16 —- 2.33 [obscured signal, 4H, —N(CH3)CH2CH2CH2],

3.01 (s, 3H, N—CH3),

3.45 — 3.65 [m, 5H, —N(CH3)CH2CH2CH2, —SCH2—),

3.95 (d, 1H, J = 17 Hz, — SCH2—), 4.04 (d, 1H, J = 14 Hz,

I r ¹ o

4.08 [s, 3H, — OCH3), 4.75 (d, 1H, I = 14 Hz,

5.37 (d, 1H, J = 5 Hz, C-6 β-lactam), 5.86 (d, 1H, J = 5 Hz, C-7 β-lactam),

7.16 (s, 1H, C—5 of thazol).

Analysis for: C19H24N6O5S2 . H2SO4 calculated:

39.43% C, 4.53% H, 14.53% N, 16.63% S, found:

39.40% C, 4.47% H, 14.39% N, 16.60 °/o S.

Example 19

7- [α-(2-aminothiazol-4-yl)-α-(Z)-methoxyiminoacetamido]-3-((4-methyl-4-morpholinium)methyl-3-cephem-4-carboxylate '0 _X OCR NH ' aV·

N—I lj ^£ ' . Ó ^u o

OI i, co ^Ch sz <- ^,H a ^so 4

I % j what _s

CH

40

The title compound was prepared according to the procedure described in Example 18 from 54.0 g (122 mmol) of (6R,7R)-7-amino-3-(4-methyl-4-morpholinio)methylcep-3-em-4-carboxylate monohydroiodide (prepared in Example 13) and 59.0 g (184 mmol; 1.5 equivalents) of activated syn-2-(2-aminothiazol-4-yl)-2-methoxyiminoacetic acid hydroxybenzotriazolyl ester.

In this way, a total of 60.1 g (84%) of the white crystalline title compound is obtained in the form of the sulfuric acid salt.

⁴ H-NMR (360 MHz, deuterium oxide/deuterated sodium bicarbonate, ó'j values:

4.95 (d, 1H, J = 14 Hz, +/—\ ~CH,N O j

5.47 (d, 1H, J = 5 Hz, C-6 β-lactam),

5.96 (d, 1H, J = 5 Hz, C-7 of O-lactam), 7.10 (s, 1H, C-5 of thiazole.

Analysis for: C19H24N6O6S3. H2SQ4

3.30 (s, 3H, NCH3),

3.55 [m, 5H, — N (CH3)CH2CH2OCH2CH2, —SCHz—1,

4.05 (d, 1H, J = 16 Hz, —SCH2—), 4.10 (s, 3H, —OCH3),

4.1 [m, 4H, — N(CH3)CH2CH2OCHzCH2],

4.21 (d, 1H, J = 14 Hz,

-'CH NO ), ch ₅ .

Table of compound yield (example) (%)

12 57 13 41 14 95 15 78 16 >100 ^days > 17 >100 ^days

Legend:

calculated:

38.37% C, 4.41% H, 14.13% N, 16.18% S, ϋί)1Ρ7ΡΠΠ'

38.16% C, 4.32% H, 14.08% N, 16.14 °/o S.

Example 20

The following table summarizes the results obtained from the analyses of the products of some of the examples. With the exception of the compounds of examples 12 and 13, the data reported relate to the sulfuric hydroiodides isolated by filtration of the suspension after the addition of methanol. The compounds of examples 12 and 13 were isolated from this suspension after the addition of 3N aqueous hydroiodic acid.

purity of A ³ -isomer:ru (% area HPLCj ratio of A ³ : A ² -isomer HPLC ^a) NMR ^b) 97 97 : 0 — >95 >95:0 — 65 ^cents > 65 : 6 — 92 92 : 0 — 24 24 : 34 1 : 1.7 16 16 : 80 1 : 3.3

^and, the data reported are the area percentages for each isomer on the chromatogram obtained by high-performance liquid chromatography of the isolated salt with hydroiodic acid;

^b, the reported data is the ratio of isomers obtained by comparative integration of signals for individual isomers;

^(c) the main impurity is pyridine hydroiodide (24 area %);

^d) The NMR spectrum of the hydriodic acid salt of the sulfite, measured at 360 MHz, indicates that the main impurity is the unreacted starting amine.

Claims (3)

SUBJECT VYNALEZU A process for the production of temperature-stable crystalline cephalosporins of the formula VIIIb IVU b) in 1,1,2-trichlorotrifluoroethane operate in any order at least one equivalent of iodotrimethylsilane and at least one equivalent of a compound of formula b is running / \ "...... / _CH3 in... where X is hydrogen chloride or hydrogen iodide and, 4-Nu is a radical of formula CH ₃ from the resulting product by treatment with a lower alkanol and removing the silyl group product is acidified with hydrogen chloride or hydrogen iodide. 2. A process according to claim 1, wherein the corresponding starting materials are used to form compounds of formula VIIIb wherein X is as defined above + and —Nu represents a radical of formula virtually free of the A ² -isomer, characterized in that a solution of the compound of formula IVa UV &.} 3. A process according to claim 1 or 2, wherein the corresponding starting materials are used to form a compound of formula VIIb wherein -Nu is a 1-methyl-1-pyrrolidinium radical and X is as defined above.