WO1996012712A1

WO1996012712A1 - Reactive phosphate derivatives of thiazolylacetic acid and process for preparing cephalosporin antibiotics using the same

Info

Publication number: WO1996012712A1
Application number: PCT/KR1995/000136
Authority: WO
Inventors: Tae-Won Kang; Woong-Sig Moon; Yoon-Whan Choi; Ki-Jun Hwang
Original assignee: Miwon Co., Ltd.
Priority date: 1994-10-24
Filing date: 1995-10-23
Publication date: 1996-05-02

Abstract

The present invention relates to a novel reactive phosphate derivative of thiazolylacetic acid having general formula (II), which is useful as an intermediate for preparing cephalosporin derivatives: in which R represents hydrogen, C1-C4 alkyl or a group of the formula -C(Ra)(Rb)CO2Rc wherein Ra and Rb independently of one another represent C1-C4 alkyl or Ra and Rb together with the carbon atom to which they are attached can form C3-C7 cycloalkyl, and Rc represents hydrogen or a carboxyl-protecting group; and R1 represents C¿1?-C4 alkyl, and to a process for preparing thereof and to a process for preparing cephalosporin antibiotics using the said reactive phosphate derivative of formula (II).

Description

REACTIVE PHOSPHATE DERIVATIVES OF THIAZOLYLACETIC ACID AND PROCESS FOR PREPARING CEPHALOSPORIN ANTIBIOTICS

USING THE SAME

TECHNICAL FIELD

The present invention relates to a novel reactive phosphate derivative of thiazolylacetic acid which is useful as an intermediate for preparing cephalosporin antibiotics, a process for preparation thereof and a process for preparing cephalosporin antibiotics using the same. More sepcifically, the present invention relates to a novel reactive phosphate derivative of thiazolylalky- loxyiminoacetic acid having the following gormula (II) :

in which

R represents hydrogen, C₁~C₄ alkyl or a group of formula -C(Ra) (Rb)C0₂Rc wherein Ra and Rb independently of one another represent C₁-C₄ alkyl or Ra and Rb together with the carbon atom to which they are attached can form C₃-C₇ cycloalkyl, and Re represents hydrogen or a carboxyl-protecting group; and R¹ represents C₁~C₄ alkyl, and to a process for preparing thereof.

In addition, the present invention also relates to a process for preparing cephalosporin antibiotics using the said reactive phosphate derivative of formula (II) . BACKGROUND ART

According to the known methods for preparing cephalos¬ porin antibiotic compounds described in prior publications and patents, the cephalosporin antibiotic compounds have been generally prepared by converting the starting organic acid compound represented by the' following formula (I) into the reactive derivative thereof, which is then sub¬ jected to acylation reaction with the amino group of beta- lactam nucleus of 7-aminocephalosporanic acid (hereinaf¬ ter, referred to as "7-ACA") to form an amide linkage.

In the above formula,

R represents hydrogen, C₁~C₄ alkyl or a group of formula -C(Ra) (Rb)C0₂Rc wherein Ra and Rb independently of one another represent ₁-C₄ alkyl or Ra and Rb together with the carbon atom to which they are attached can form C₃-C₇ cycloalkyl, and Re represents hydrogen or a carboxyl-protecting group.

As the reactive derivative of the compound of formula (I) as above, an acid chloride, a reactive ester, a reac¬ tive amide or a mixed acid anhydride has been generally used. Among those reactive derivatives, when the acid chloride is used, in general, the acid chloride is pre- pared by reacting the organic acid compound of formula (I) with a chlorinating agent such as thionyl chloride, phos¬ phorus trichloride, phosphorus oxychloride or phosphorus pentachloride at lower temperature and then is reacted with 7-ACA derivative to prepare the desired cephalosporin antibiotic compound (see, U.S. Patent Specification 4,202,893, British Early Published Patent No. 2025933, Japansese Early Published Patent No. (sho) 52-102293) . However, this method has some disadvantages in that the procedure includes the steps for introducing a protecting group into amino group and then removing the protecting group in the compound (I) and therefore is complicated, and further, the acid chloride as produced during the procedure is very unstable to cause the quality deteriora¬ tion of the final product.

In addition, the compound of formula (I) can be con- verted into the reactive ester which is then used for preparing the cephalosporin compounds. Specifically, in this case, the organic acid of formula (I) is reacted with 1-hydroxybenzotriazole or 2-mercaptobenzothiazole in the presence of dicyclohexylcarbodiimide (hereinafter, re- ferred to as "DCC") to produce the reactive ester of the organic acid which is then reacted with the 7-ACA deriva¬ tive to prepare the desired cephalosporin antibiotic compound. However, this method has also disadvantages in that since as the reaction by-products the ester-forming step produces dicyclohexylcarbodiimide and the step for reacting with 7-ACA also produces; 1-hydroxybenzotriazole or 2-mercapto-benzothiazole, such by-products should be removed either by dissolving them in an organic solvent or using any other method and thus the whole procedure is complicated, and further that the acylation requires a long reaction time and the yield and quality of the final desired product are low (see, U.S. Patent Specifications 4,576,749 and 4,548,748, European Patent No. 0 175 814 A2) .

As an improved alternative for such reactive deriva¬ tives, Korean Laid-open Patent Publication No. 94-23915 /12712 -

(November 17, 1994) discloses the reactive thiophosphate derivative of organic acid having the following formula (A) as the intermediate for preparing cephalosporins:

in which

R¹ represents hydrogen or an aminό-protecting group; R² represents hydrogen, C₁-C₄ alkyl or a group of formula -C(Ra) (Rb)C0₂Rc wherein Ra and Rb are identical to or different from each other and Ra and Rb together with the carbon atom to which they are attached can form C₃-C₇ cycloalkyl, and Re represents hydrogen or a carboxyl-protecting group; R³ represents ^-C_^j alkyl or phenyl or R³ together with the oxygen and phosphorus atoms to which it is at- tached can form a 5- to 6-membered heterocyclic ring; and Q represents N or CH.

However, although such reactive thiophosphate deriva- tive achieves the desired improvement in view of the reactivity and stability, it has- some disadvantages in that before the reactive thiophosphate derivative (A) as synthesized is used in the acylation reaction, the reac¬ tion mixture should be subjected to additional steps for neutralization, layer separation, concentration, recrys- tallization, filtration and drying in order to remove the by-products including catalyst, base, etc., and the de- sired final cephalosporin derivative prepared form the reactive thiophosphate compound (A) has undesirable color and odor originated from the sulfur compound produced from the reactive thiophosphate derivative. Since such color- ing and odor necessarily requires the incidental proce¬ dures, for example, recrystallization or purification, for removing any color and odor from the final product and, therefore, causes a lowering of the recovery yield of the final product, the use of the reactive thiophosphate derivatie (A) is also not preferable in economical view.

As described above, since the reactive derivatives of organic acid (I) in the prior art have numerous problems, the present inventors have extensively studied to find out the means for simply and efficiently preparing the desired cephalosporin antibiotic compound in high yield and in high quality, which does not require any additional step for introducing or removing the protecting group for amino group present in the organic acid (I) and does not have the disadvantages involved in the reactive derivatives used in the prior methods. As a result, we have identi¬ fied that when the novel reactive phosphate derivative of formula (II) , as defined above, is used as an intermediate compound, such purpose can be achieved. Thus, we have completed the present ivnention.

DISCLOSURE OF INVENTION

Therefore, it is an object of the present invention to provide a novel reactive phosphate derivative of thiazoly- lacetic acid represented by the following formula (II) :

in which R represents hydrogen, -_^-^ alkyl or a group of formula -C(Ra) (Rb)C0₂Rc wherein Ra and Rb independently of one another represent C^-C^ alkyl or Ra and Rb together with the carbon atom to which they are attached can form C₃-C₇ cycloalkyl, and Re represents hydrogen or a carboxyl-protecting group; and R¹ represents C^-C^ alkyl.

It is another object of the present invention to provide a process for preparing a reactive phosphate derivative of thiazolylacetic acid represented by the following formula (II) :

in which

R represents hydrogen, ^ -C^ alkyl or a group of formula -C(Ra) (Rb)C0₂Rc wherein Ra and Rb independently of one another represent C^-C^ alkyl or Ra and Rb together with the carbon atom to which they are attached can form C₃-C₇ cycloalkyl, and Re represents hydrogen or a carboxyl-protecting group; and R¹ represents ^-C₄ alkyl, characterized in that an aminothiazole derivative repre¬ sented by the following formula (I) :

wherein R is defined as above, is reacted with a chloro- phosphate represented by the following formula (III) :

Cl P—OR¹ (HI)

I OR¹

wherein R¹ is defied as above,

In addition, it is a further object of the present invention to provide a process for preparing a cephem derivative represented by the following formula (V) :

in which

R represents hydrogen, C₁-C₄ alkyl or a group of formula -C(Ra) (Rb)C0₂Rc wherein Ra and Rb independently of one another represent C₁-C₄ alkyl or Ra and Rb together with the carbon atom to which they are attached can form C₂ -C₇ cycloalkyl, and Re represents hydroegn or a carboxyl-protecting group;

X represents O, S or N and R³ represents a group of for-

mula -C-CH₃ or , or _CHo

X and R together represent a group of formula

represents hydrogen or sodium or represents an inter nal salt, characterized in that a compound represented by the fol¬ lowing formula (II) :

wherein R is defined as above and R¹ represents C^-^ alkyl, is reacted with an 7-ACA derivative represented by the following formula (IV) :

wherein X and R³ are defined as above and R represents hydrogen or a carboxyl-protecting group, in an organic solvent in the presence or absence of a base.

BRIEF DESCRIPTION OF DRAWINGS

For a thorough understanding of the nature and objetcs of the invention, reference should be had to the following detailed description taken in connection with the accompa- nying drawings in which:

Figure 1 is IR spectrum of the reactive phosphate derivative prepared in Example 2 according to the present invention;

Figure 2 is ¹H-NMR spectrum of the reactive phosphate derivative prepared in Example 2 according to the present invention; and

Figure 3 is ¹ C-NMR spectrum of the reactive phosphate derivative prepared in Example 2 according to the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

In one aspect, the present invention relates to novel reactive phosphate derivative of thiazolylalkyloxyi- minoacetic acid represented by the following formula (II) , which is useful as an intermediate in preparing cephalos¬ porin antibiotic compounds:

in which R represents hydrogen, C₁-C₄ alkyl or a group of formula -C(Ra) (Rb)C0₂Rc wherein Ra and Rb independently of one another represent C₁-C₄ alkyl or Ra and Rb together with the carbon atom to which they are attached can form C₃-C₇ cycloalkyl, and Re represents hydrogen or a carboxyl-protecting group; and R¹ represents C - ^ alkyl.

In the definitions of substituents as mentioned above and hereinafter, as the carboxyl-protecing group any protecting group which is conventionally used in the field of preparation of cephalosporin antibiotics can be used. For example, the following can be mentioned: lower alkyl group (e.g. methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, pentyl, hexyl,. etc.), lower alkanoy- loxy(lower)alkyl (e.g. acetoxymethyl, propionyloxymethyl, butyryloxymethyl, valeryloxymethyl, pivaloyloxymethyl, hexanoyloxymethyl, etc.), lower alkanesulfonyl(lower)alkyl (e.g. 2-mesylethyl, etc,), lower alkoxycarbonyloxy(lower) alkyl (e.g. methoxycarbonyloxymethyl, ethoxycarbonyloxy- methyl, propoxycarbonyloxymethyl, etc.), lower alkenyl (e.g. vinyl, allyl, etc.), lower alkynyl (e.g. ethynyl, propynyl, etc.), optionally substituted aryl(lower)alkyl (e.g. benzyl, 4-methoxybenzyl , phenylethyl, trityl, benzhydryl, etc.) , optionally substituted aryl (e.g. phenyl, 4-chlorophenyl , tolyl, t-butylphenyl , xylyl, mesityl, cumenyl, etc.), tri (lower) alkylsilyl (e.g. trime- thylsilyl, triethylsilyl, isopropylidenedimethylsilyl, t- butyldimethylsilyl, diisopropylmethylsilyl, etc.) , tria- rylsilyl (e.g. triphenylsilyl, etc.), triaryl (lower) alkyl¬ silyl (e.g. tribenzylsilyl, etc.) , diaryl (lower) alkylsilyl (e.g. diphenyl t-butylsilyl) , and the like groups.

In considering the reactivity, the preferable one of the reactive phosphate derivative of formula (II) accord¬ ing to the present invention is the compound wherein R represents C₁~C₄ alkyl or a group -C(Ra) (Rb)C0₂Rc wherein Ra and Rb independently of one another represent C,-C₄ alkyl and Re represents hydrogen or C₁-C₄ alkyl, and R¹ represents C,-C₂ alkyl.

Particularly preferred reactive phosphate derivative of formula (II) is the compound wherein R represents methyl or a group -C(Ra) (Rb)C0₂Rc wherein Ra and Rb inde¬ pendently of one another represent methyl and Re repre¬ sents hydrogen or butyl, and R represents ethyl.

In another aspect, the pesent invention relates to a process for preparing the compound of formula (II) . According to the process of the present invention, the desired reactive phosphate derivative of formula (II) can be obtained by reacting an organic acid of formula (I) with a phosphate compound of formula (III) . The process for preparing the reactive phosphate derivative of formula (II) according to the present invention can be represented by the following reaction scheme.

(III)

(I)

organic solvent base catalyst

(II)

In the above reaction scheme, R and R¹ are defined as above.

In conducting the above reaction for preparing the reactive phosphate derivative of formula (II) , the phos- phate compound of formula (III) is generally used in the ratio of 0.5 to 1.5 equivalent weight, preferably 0.95 to 1.05 equivalent weight, with respect to one equivalent weight of the organic acid of formula (I) .

This reaction according to the present invention can be conducted in the presence or absence of a catalyst. Suitable catalyst which can be used in the present inven- tion includes tertiary amines such as triethylamine, 2,6- lutidine, diethylisopropylamine, pyridine, N,N'- dimethylaminopyridine, r-picoline, etc., quaternary ammo¬ nium salts such as tetra ethylguanidine, etc., or saccha- rin, with saccharin being most preferably used. Although the reaction can be practiced in the absence of a cata¬ lyst, in general, the reaction is preferably carried out in the presence of a catalyst since the reaction under the catalyst does not produce any reaction by-product and can be completed within a short period under mild reaction condition. It is preferable to use the catalyst in the molar ratio of 0.1 to 5% with respect to the organic acid of formula (I) .

This reaction can be preferably carried out in the presence of a solvent. As the solvent which is suitable for this purpose, any organic solvent which does not adversely affect the reaction can be used. Preferably, a polar or non-polar solvent, for example, dichloromethane, dichloroethane, chloroform, carbon tetrachloride, xylene, acetone, acetonitrile, ethyl acetate, dioxane, tetrahy- drofuran, NjN'-dimethylformamide, N,N'-dimethylacetamide, dimethylsulfoxide, etc., can be used. If necessary, in order to optimize the reactivity and the yield of the final product, a mixture of two or more solvents can also be used.

The above reaction according to the present invention can be preferably carried out in the presence of a base to remove the acid (HC1) liberated from the reaction. The base which can be suitably used for this purpose includes diisopropylethylamine, triethylamine, diethylamine, tri-n- butylamine, tetramethylguanidine, pyridine, 2,6-lutidine, 2,4,6-collidine, etc.

The reaction is generally carried out at the tempera¬ ture in the range of -40°C to 60°C, and preferably at 25°C. The reaction time is generally 0.5 to 2 hours and preferably 30 minutes.

The present invention also relates to a process for preparing cephalosporin compounds of formula (V) using the reactive phosphate derivative of formula (II) , as depicted in the following reaction scheme.

(V)

In the above reaction scheme,

R and R¹ are defined as above,

R² represents hydrogen or a carboxyl-protecting group,

X represents S, 0 or N and R³ represents a group of

formula -

X and R³ together can form a group of formula

R represents hydrogen or sodium or represents an inter¬ nal salt.

According to the above method, the cephalosporin anti¬ biotic compound of formula (V) can be obtained by acylat- ing 7-ACA derivative of formula (IV) with the reactive phosphate derivative of formula (II) . This reaction can be preferably conducted under conditions conventionally used in preparing the cephalosporin antibiotics.

After the reactive phosphate derivative of formula (II) used as the intermediate compound in this reaction is prepared, it can be separated, purified and then intro- duced in the reaction. However, in general, the reactive phosphate derivative of formula (II) as prepared is not separated from the reaction solution and is successively subjected to the acylation reaction with the 7-ACA deriva¬ tive of formula (IV) to prepare the cephalosporin antibi- otics.

The 7-ACA derivative (IV) used as the reactant in this reaction can be used in the protected (R² = carboxyl- protecting group) or non-protected (R² = H) form at 3- n , carboxyl group. When R* is a carboxyl-protecting group, any of said carboxyl-protecting groups can be suitably used as the protecting group, but the carboxyl group of R² is preferably protected in the silylated form. The silylating agent which can be appropriately used for protecting the carboxylic group in the silylated form includes dichloro ethylsilane, trichloromethylsilane, hexa ethyldisilazane, N,0-bis-trimethyIsilylacetamide, N,N'-bis-trimethylsilylurea, etc., with N,0-bis-trimethyl- silylacetamide or N,N'-bis-trimethylsilylurea being most preferably used.

When the 7-ACA derivative of formula (IV) wherein R is a carboxyl-protecting group, particularly a silyl group, is used as the reactant, this compound can be previously prepared and then used for the reaction with the reactive phosphate derivative of formula (II) . However, the compound of formula (IV) can be allowed to participate in the reaction in the form of the compound wherein R² is protected by reacting the compound of formu¬ la (IV) wherein R is hydrogen with the reactive phosphate derivative of formula (II) in the presence of a silylating agent. In this case, the silylating agent can be used in the ratio of 0.1 to 5 equivalent weight, preferably 0.9 to 1.1 equivalent weight, with respect to one equivalent weight of the 7-ACA derivative of formula (IV) wherein R² is hydrogen.

In addition, the above reaction for preparing the cephalosporin derivative of formula (V) according to the present invention can be practiced in the presence of a suitable base and solvent. As the base which can be preferably used for this purpose, diisopropylethylamine, triethylamine, diethylamine, tri-n-butylamine, tetrameth¬ ylguanidine, pyridine, 2,6-lutidine, 2,4,6-collidine, etc. can be mentioned. The base is used generally in the ratio of 0.1 to 5 equivalent weight, preferably 1 to 3 equivalent weight, with respect to one equivalent weight of the 7-ACA derivative of formula (IV) . Although any organic solvent which does not adversely affect the rac- tion can be used as the solvent for this reaction, one selected from the group consisting- of methylene chloride, acetonitrile, N,N-dimethylformamide, tetrahydrofuran, chloroform, ethyl acetate, 1,2-dimethoxyethane, dioxane, toluene and benzene, or a mixture of two or more selected therefrom can be preferably used.

The acylation reaction of the reactive phosphate derivative of formula (II) with the 7-ACA derivative of formula (IV) generally requires 0.5 to 5 hours and most preferably 1 to 3 hours.

After the reaction is completed, the resulting desired cephalosporin antibiotic compound of formula (IV) can be readily separated from the reaction solution by optionally treating with an acid to remove the protecting group with acid hydrolysis and, at the same time, crystallizing and then filtering the product. The acid which can be pref¬ erably used for such working-up procedure includes all of the organic acids, hydrochloric acid, phosphoric acid, sulfuric acid, etc. , with dilute hydrochloric acid being preferably used.

Alternatively, if required, the resulting compound of formula (V) wherein R⁴ is hydrogen can be converted into its sodium salt according to the method conventionally used in the field of preparation of cephalosporin antibi¬ otic compounds.

Particular advantages of the present invention which are provided by preparing the cephalosporin compounds (V) using the novel reactive phosphate derivative of formula (II) according to the present invention are as follows:

1. Since the reactive phosphate derivative of formula

(II) can be prepared starting from the compound of formula (I) under mild reaction conditions and then, without separation, reacted with the compound of formula (IV) to prepare the compound of formula (V) , the reaction can be simply conducted in the one-step procedure and, therefore, the desired cephalosporin derivative can be prepared under economically advanta- geous conditions.

2. Since the amino group of the compound of formula (I) does not require to protect, the reaction procedure is shortened and thus is economical.

3. Since the cephalosporin compound of formula (V) can be prepared without any reaction by-product, it does not require any special procedure and apparatuse for removing by-products.

4. The use of the novel reactive phosphate derivative of formula (II) as an acylating agent provides the advan¬ tages in that since the final product can be prevented from coloring in comparison with the prior art and, therefore, no recrystallization and purification procedure for removing any color of the product is included, the recovery yield of the final product increases.

5. Since the reaction time is relatively shortened in comparison with the prior art, the economical advan¬ tage is provided.

The present invention is not limited only to the above-mentioned technical constitution. In this connec¬ tion, it should be understood that an analogue of the compound of formula (II) can be prepared using the corre¬ sponding analogue of the compound of formula (I) , and an analogue of the cephalosporin compound of formula (V) can also be synthesized by combining the cephem derivative of formula (IV) with said analogue of the compound of formula (II) in the same manner as mentioned above. All of such cases are included in the present invention.

The present invention will be more specifically illus¬ trated in the following examples. However, it should be understood that the present invention is not limited to these examples in any manner.

EXAMPLE 1

Synthesis of diethylphosphoryl ( Z )-2- (2-amino-4-thiazolγl) -2-(t-butoxycarbonyl-dimethylmethoxyimino)acetate

In a three neck flask 3.7g(1.84 mmole) of (Z)-2-(2- amino-4-thiazolyl)-2-(t-butoxycarbonyl-dimethylmethoxyimi- no)acetic acid and 2.66ml(1.84 mmole) of diethylchloro- phosphate were dissolved in 40ml of dichloro ethane. To this mixture was slowly added dropwise the solution of 2.62ml(1.88 mmole) of triethylamine and O.lg of saccharin dissolved in 10ml of dichloromethane, at 20°C over one hour. This reaction mixture was stirred for one hour at room temperature to produce the clear solution to which 50ml of 5% sodium bicarbonate solution was added to sepa¬ rate the layers. The organic layer was separated, washed with 50ml of saline, dried over anhydrous sodium sulfate and then filtered. The filtrate was distilled under reduced pressure. 50ml of n-hexane was added to the residue. The precipitated crystal was filtered and dried to obtain 5.71g(Yield 91%) of the title compound having a pale yellow color.

^λE NMR(DMSO-dg) : δ 1.4(m, 6H, -0CH₂CH₃), 2.80(-thiazole) , 3.2(m, 4H, -OCH₂CH₃), 8.40(-(CH₃)₂) , 8.66(s, t-butyl) , 7.45(bs, 2H, -NH₂)ppm

EXAMPLE 2

Synthesis of diethylphosphoryl (Z)-f2-amino-4-thiazolyl)- methoxyi inoacetate

In a three neck flask 5.55g(2.76 mmole) of (Z)-(2- amino-4-thiazolyl) -2-syn-methoxyiminoacetate and 4.0ml (2.76 mmole) of diethylchlorophosphate were added and then suspended by adding 60ml of dichloromethane. To this suspension was slowly added dropwise the mixed solution of 3.93ml(2.82 mmole) of triethylamine, 15ml of dichloro eth- ane and 0.15g of saccharin at 20°C over one hour. The resulting mixture was successively stirred while reducing the stirring rate. Then, the mixture was stirred for further one hour at 20°C to form a clear solution to which 50ml of 5% sodium bicarbonate solution was added to sepa- rate the layers. The organic layer was separated, washed with 50ml of saturated saline, dried over anhydrous sodium sulfate and then filtered. The solvent was removed from the filtrate under reduced pressure and 50ml of n-hexane was added to the residue to precipitate the crystal. The resulting crystal was filtered and dried to obtain 5.5g (Yield 90%) of the title compound having a pale yellow color.

¹H NMR(DMSO-dg) : <5 1.4 (m, 6H, -OCH₂CH₃) , 3.95(s, 3H, N-CH₃), 3.2(m, 4H, -OCH₂CH₃), 7.0(s, 1H, thiazole) , 7.45(bs, 2H, NH₂)ppm

¹³C NMR(DMSO-dg) : <5 15.7, 15.8, 63.0, 65.3, 65.5, 108.5,

139.7, 145.0, 145.2, 156.6, 169.1 ppm

IR(cm^"1) : 1775(C=0), 1265(P=0), 1000-1100, 900(P=OOCH₂)

Melting point : 98-100°C

EXAMPLE 3

The reaction was carried out according to the same procedure as Example 1, except that tetrahydrofuran is used instead of dichloromethane as the solvent. After the reaction is completed, the resulting triethylamine hydrochloride was filtered off and the filtrate was con- centrated in vacuo to remove tetrahydrofuran. The residue was dissolved by adding 50ml of dichloromethane. The resulting solution was extracted with 50ml of 5% sodium bicarbonate solution. The extract was washed with 50ml of saturated saline, dried over anhydrous sodium sulfate and then filtered. The solvent was removed from the filtrate in vacuo and 50ml of n-hexane was added to the residue to precipitate the crystal. The resulting crys¬ tal was filtered and dried to obtain 5.6g (Yield 92%) of the same pale yellow compound as the title compound of Example 1.

EXAMPLE 4

The reaction was carried out. according to the same procedure as Example 2, except that diethylacetamide is used instead of tetrahydrofuran as the solvent, to obtain

5.4g (Yield 89%) of the same compound as the title com- pound of Example 2.

EXAMPLE 5

The reaction was carried out according to the same procedure as Example 2, except that acetonitrile is used instead of tetrahydrofuran as the solvent, to obtain 5.31g (Yield 87%) of the same compound as the title compound of Example 2.

EXAMPLE 6

The reaction was carried out according to the same procedure as Example 1, except that 5% molar equivalent of

N,N'-dimethylaminopyridine is used instead of saccharin, to obtain 5.3g (Yield 87%) of the same compound as the title compound of Example 1.

EXAMPLE 7 Synthesis of Cefotaxi e free acid

5g(1.83 mmole) of 7-ACA was added to 100ml of dichlo¬ romethane and then 5ml(1.83 mmole) of N,0-bistrimethylsi- lylaceta ide(BSA) was added thereto. The reaction mix- ture was stirred for one hour at 30°C. To this mixture was added dropwise the phosphate compound, as obtained in Example 2 but not separated, in the form of the reaction solution and this mixture was stirred for one hour at 25°C. To this reaction mixture was added 100ml of dis- tilled water. The reaction solution was stirred for 5 minutes to separate the layers. The aqueous layer was adjusted to pH 2.7 using 6N-hydrochloric acid solution and then stirred for one hour. The resulting product was filtered and dried to obtain 8.03g (Yield 96%) of Cefotax- ime free acid having a pale yellow color.

¹H NMR(DMSO-d₆) : S 2.1(s, 3H) , 3.6(bs, 2H) , 3.9(s, 3H) , 4.9(m, 2H) , 5.2(d, 1H, J=5Hz) , 5.8(dd, 1H, J=5.8Hz), 6.8(s, 1H) , 9.6(d, 1H, J=8Hz)ppm

EXAMPLE 8

Synthesis of Cefotaxime free acid

44.26g(0.22 mmole) of Z-(2-amino-4-thiazolyl)methoxyi- minoacetic acid was suspended in 400ml of methylene chlo¬ ride and 31.8ml(0.22 mole) of diethylchlorophosphate was added thereto. To this mixture was added dropwise the solution of 2.5g of saccharin and 31πl(0.22 mole) of triethylamine dissolved in 50ml of methylene chloride over one hour. To the resulting solution was added dropwise the solution of 50g(1.84 mole) of 7-ACA and 50ml(3.58 mole) of triethylamine dissolved in 300ml of methylene chloride at 20°C. This mixture was reacted for 2 hours at 20°C and then 200ml of distilled water was added there¬ to. This solution was stirred for 10 minutes to separate the layers. The aqueous layer was adjusted to pH 2.7 using 6N-hydrochloric acid. The resulting product was filtered and dried to obtain 70.34g (Yield 95%) of Cefo¬ taxime free acid having a pale yellow color.

EXAMPLE 9

5g(1.83 mmole) of 7-ACA was suspended in 100ml of methylene chloride and then dissolved by adding 5ml of triethylamine. The resulting solution was added to the solution of 6.11g(2.03 mmole) of the compound which was prepared in Example 2 and dissolved in 50ml of methylene chloride, and the mixture was reacted for one hour at 20°C. The reaction solution was then treated according to the same manner as Example 8 to obtain δ.llg (Yield 97%) of Cefotaxime free acid.

EXAMPLE 10

The solution of 9.5g(2.9 mmole) of (6R, 7R)-7-amino- 3-(l-methylpyrrolidino)methyl-3-cephem-4-carboxylic acid hydrochloride and 2.6g(2.9 mmole) of triethylamine dis¬ solved in 100ml of methylene chloride was added dropwise to the dichloromethane solution of the reactive phosphate compound, as prepared in Example 2 , over 10 minutes. The mixture was reacted for one hour at 20°C and then 200ml of distilled water was added thereto. The reaction mixture was stirred for 10 minutes to separate the layers. The aqueous layer was adjusted to pH 2.7 using 6N-hydrochloric acid to precipitate the solid product which was then filtered and dried to obtain 11.46g (Yield 93%) of 7- [ (Z) -2-(2-aminothiazol-4-yl)-2-methoxyiminoacetamido]-3-(i -methylpyrrolidino)methyl-3-cephem-4-carboxylic acid.

¹H NMR(DMSO-dg) : δ 2.31(m, 4H, pyrrolidine-H) , 3.08(s, 3H, NCH₃), 3.63 (m, 4H, pyrrolidine-H) ,

4.09(S, 3H, OCH₃), 5.43(d, 1H, 6-H, J=4.8Hz),

5.93 (dd, 1H, 7-H) , 7.08 (s, 1H, thiazole-H)ppm

EXAMPLE 11

The solution of 10g(2.6 mmole) of 7-amino-3- [ (5- carboxymethyl-4-methylthiazol-2-yl)thiomethyl]-3-cephem-4- carboxylic acid and 3g(2.6 mmole) of tetramethylguanidine dissolved in 100ml of methylene chloride was added drop¬ wise to the dichloromethane solution of the reactive phosphate derivative, as prepared in Example 2, over 30 minutes. This mixtrue was stirred for 30 minutes at 20°C and 150ml of distilled water was added thereto. The reaction mixture was stirred for further 10 minutes to separate the layers. The aqueous layer was adjusted to pH 2.5 using lN-hydrochloric acid and then stirred for 30 minutes to precipitate the solid product which was fil¬ tered and dried to obtain 14.4g (Yield 96%) of 7-[α-(Z)- methoxy-imino-Q.-(2-amino-4-thiazolyl)acetamido]-3-[ (5-car- boxymethyl-4-methylthiazol-2-yl)thiomethyl]-3-cephem-4- carboxylic acid having a pale yellow color.

^-H NMR(DMSO-dg) : <5 2.2 (s, 3H, CH₃), 3.6(ABq, 2H, 2-CH₂), 3.75(S, 2H, CH₂), 3.85(s, .3H, -NOCH₃), 4.25(ABq,

2H, 3-CH₂), 5.1(d, 1H, 6-H) , 5.75(dd, 1H, 7-H) , 6.7(s, 1H, thiazole-H) , 7.15(bs, 2H, NH₂) , 9.5(d, 1H, NH)ppm

EXAMPLE 12 The solution of 9.3g(2.9 mmole) of 7-amino-3-methyl- 2,3-cyclopenteno-4-pyridinocephalosporanic acid hydrobro- mide and 5.9g(2.9 mmole) of N,N*-trimethylsilylacetamide dissolved in 100ml of dichloromethane was added dropwise to the dichloromethane solution of the reactive phosphate compound, as prepared in Example 1, over 10 minutes. This mixture was reacted for one hour at 20°C and then 100ml of distilled water was added thereto. The reaction mixture was stirred for 10 minutes to separate the layers. The aqueous layer was adjusted to pH 2.5 using lN-hydro- chloric acid to precipitate the solid product which was then filtered and dried to obtain 13.Og (Yield 93%) of (6R,7R)-7-[ (Z)-2-(2-amino-4-thiazolyl)-2-(2-methoxyimino)- acetamido]-3-[ (2,3-cyclopenteno-1-pyridino)methyl]-3-ceph- em-4-carboxylic acid internal salt having a pale yellow color.

^-H NMR(DMSO-dg) : δ 2.12-2.30(2H, m, cyclopentyl) , 3.06-

3.17(2H, m, cyclopentyl), 3.20-3.31(2H, m, cyclo- pentyl) , 3.41(2H, ABq, J=18Hz, CH₂S) , 3.80(3H, s,

OCH₃), 5.18(1H, d, J=5HZ, CH) , 5.44, 5.55(2H, ABq, J=15HZ, CH₂N) , 5.85(1H, dd, J=5.8Hz, CH) , 6.71(1H, S, thiazole H) , 7.92-8.68 (3H, m, pyridine H) , 9.66(1H, d, J=8Hz, amide NH)ppm

Claims

WHAT IS CLAIMED IS

1. A reactive phosphate derivative of thiazolylacet- ic acid represented by the following formula (II) :

in which

R represents hydrogen, C₁-C₄ alkyl or a group of formula -C(Ra) (Rb)C0₂Rc wherein Ra and Rb independently of one another represent C^-C^ alkyl or Ra and Rb together with the carbon atom to which they are attached can form C₃-C₇ cycloalkyl, and Re represents hydrogen or a carboxyl-protecting group; and

R represents C₁-C₄ alkyl.

2. The reactive phosphate derivative of formula (II) as defined in claim 1, wherein R represents C -C₄ alkyl or a group of formula -C(Ra) (Rb)C0₂Rc, Ra and Rb independent- ly of one another represent C₁-C₄ alkyl. Re represents hydrogen or C-^-^ alkyl and R¹ represents Cι-C₂ alkyl.

3. The reactive phosphate derivative of formula (II) as defined in claim 2, wherein R represents methyl or a group of formula -C(Ra) (Rb)C0₂Rc, Ra and Rb independently of one another represent methyl, Re represents hydrogen or butyl and R¹ represents ethyl ,

4 . A process for preparing a reactive phosphate derivative represented by the following formula ( II) :

in which

R represents hydrogen, C^-C^ alkyl or a group of formula -C(Ra) (Rb)C0₂Rc wherein Ra and Rb independently of one another represent C^C^ alkyl.or Ra and Rb together with the carbon atom to which they are attached can form C₃-C₇ cycloalkyl, and Re represents hydrogen or a carboxyl-protecting group; and R¹ represents C₁-C₄ alkyl, characterized in that an aminothiazole derivative repre¬ sented by the following formula (I) :

O

wherein R¹ is defiend as above,

5. The process for preparing the reactive phosphate derivative of formula (II) as defined in claim 4, charac¬ terized in that the reaction is carried out in the presence of a catalyst.

6. The process for preparing the reactive phosphate derivative of formula (II) as defined in claim 5, charac- terized in that the catalyst is one or more substance selected from the group consisting of secondary or ter¬ tiary amines, quaternary ammonium salts, phosphonium salts and saccharin.

7. The process for preparing the reactive phosphate derivative of formula (II) as defined in claim 4, charac¬ terized in that the reaction is carried out in the presence of a base.

8. The process for preparing the reactive phosphate derivative of formula (II) as defined in claim 7, charac¬ terized in that the base is selected from the group con- sisting of diisopropylethylamine, triethylamine, diethyla- mine, tri-n-butylamine, tetramethylguanidine, pyridine, 2,6-lutidine and 2,4,6-collidine.

9. A process for preparing a cephem derivative represented by the following formula (V) :

in which R represents hydrogen, C._|_-C₄ alkyl or a group of formula -C(Ra) (Rb)C0₂Rc wherein Ra and Rb independently of one another represent C^- ^ alkyl or Ra and Rb together with the carbon atom to which they are attached can form C₃-C₇ cycloalkyl, and Re represents hydrogen or a carboxyl-protecting group;

X represents 0, S or N and R³ represents a group of for¬

X and R³ together represent a group of formula

R⁴ represents hydrogen or sodium or represents an inter¬ nal salt, characterized in that a compound represented by the fol¬ lowing formula (II) :

wherein R is defined as above and R¹ represents Cm -C . alkyl , is reacted with an 7-ACA derivative represented by the following formula (IV) :

wherein X and R are defined as above and R² represents hydrogen or a carboxyl-protecting group, in an organic solvent in the presence or absence of a base.

io. The process for preparing the cephem derivative of formula (V) as defined in claim 9, characterized in that the reaction is carried out in the presence of a base selected from the group consisting of diisopropylethyla¬ mine, triethylamine, diethyla ine, tri-n-butylamine, tetramethylguanidine, pyridine, 2,6-lutidine and 2,4,6- collidine.