JPS6127394B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an industrially advantageous method for producing 3-substituted-7-aminocephalosporanic acids from novel 5'-N-substituted cephalosporin C. The inventors of the present invention obtained a dilute solution of cephalosporin C obtained by partially purifying a culture solution of cephalosporin C obtained by a fermentation method. We discovered that cephalosporin C can be precipitated in high yield by acylating it with a curing agent to obtain a new derivative and treating it with a base such as quinoline. By the process of 3
The present inventors have discovered a method for obtaining -substituted-7-aminocephalosporanic acids in high yield, and have completed the present invention. Thus, the method of this invention can be applied to the general formula (In the formula, R ₁ is a lower alkyl group, Y is a sulfur atom or sulfinyl group, and R ₂ is a lower alkylene group.) or general formula
HS-R ₃ (in the formula, R ₃ is a heterocyclic group, which may be substituted with a methyl group) is reacted with a thiol or its salt, and the carboxyl groups at the 4- and 5'-positions of the resulting 3-substituted product are reacted. The carboxyl group is protected by converting it into an easily hydrolyzable ester or mixed acid anhydride, and the iminohalide forming agent is then reacted with a lower aliphatic alcohol to form an iminoether. Hydrolyzed to general formula (wherein X means an azide group or -S-R ₃ (R ₃ has the same meaning as above)). General formula () used as a raw material in this invention
The compound is new, and the general formula
It can be produced by reacting a reactive derivative of carboxylic acid represented by R ₁ -Y-R ₂ -COOH (in the formula, R ₁ , Y, and R ₂ have the same meanings as above), and furthermore, quinoline is added to this. By adding a base such as isoquinoline, it can be separated as a precipitate in high yield. The raw material (2) of this invention can of course be made from cephalosporin C, but industrially it is desirable to produce it directly from the above-mentioned culture solution and use it. Specific examples of the N-acyl group at the 5' position in the compound of general formula () which is a raw material for this invention include methylthioacetyl, ethylthioacetyl, isopropylthioacetyl, 2-methylthiopropionyl, methylthiopropionyl, ethylthiopropionyl, Examples include isopropylthiopropionyl, 3-methylthio-2-methylpropionyl, and their corresponding sulfinyl derivatives. Further, examples of the salts of the compound of general formula () include alkali metal salts, trialkylamine salts, quinoline salts, isoquinoline salts, etc., and cases where such salts are used as raw materials are also included in the present invention. However, it is generally better to use the compound of general formula () itself. For example, when using the quinoline salt or isoquinoline salt of the compound represented by the general formula (), these salts are sparingly soluble in water, and the first aspect of the present invention is
In carrying out the step (3-position substitution reaction), for example, the aqueous suspension is adjusted to neutrality, treated as is or treated with an organic solvent, and the aqueous solution remaining after removing the base is subjected to the reaction. The reaction between the compound of the general formula () and the alkali metal azide salt or the thiol of the general formula HS-R ₃ or its salts is usually carried out in an aqueous solvent while adjusting the pH to about 5.0 to 8.0. The aqueous solvent used here includes not only water alone but also a mixed solvent of water and an organic solvent such as an aliphatic lower alcohol (for example, methanol), acetone, or dioxane. The selection of the solvent is determined mainly by considering the solubility of the reagent to be reacted in water. The pH of this reaction can be easily adjusted, for example, by adding a phosphate buffer to the reaction solution. Slight heating is often preferred during the reaction. The thiols with the general formula HS-R ₃ used here include 1,3,4-thiadiazole-2-thiol, 5-methyl-1,3,4-thiadiazole-
2-thiol, tetrazole-5-thiol, 1
-Methyl-tetrazole-5-thiol, 1.
3,4-oxadiazole-2-thiol, 5-
Methyl-1,3,4-oxadiazole-2-thiol is an example that is preferably used to achieve the object of the present invention. The resulting 3-substituted product (i.e. 3-substituted-5'-N-
Substituted cephalosporin C) can be separated by making the pH of the aqueous reaction solution acidic and extracting it with an organic solvent. During this time, purification may be performed by activated carbon treatment, etc., if necessary. The organic solvent extract containing the 3-substituted product can be directly subjected to the next reaction. However, if water and a proton-active organic solvent are present at this time, they are removed in advance and subjected to the next reaction. The carboxyl groups at the 4- and 5'-positions of the 3-position substituted product are protected by converting them into easily hydrolyzable esters or mixed acid anhydrides upon removal of the acyl group at the 7-position. That is, as a reagent to be reacted with the 3-substituted product for this purpose, the general formula

_[ Formula _{] ( wherein} , may form a ring with P), or a phosphorus halogen compound represented by the general formula

Examples include silicon halogen compounds represented by the formula: (wherein X is a halogen atom, R ₅ is a lower alkyl group, lower alkoxy group, or halogen atom, and R ₆ and R ₇ are lower alkyl groups or lower alkoxy groups). Among these phosphorus or silicon halogen compounds, specific examples of preferred compounds include:

【formula】

[Formula] CH ₃ OPCl ₂ , C ₂ H ₅ OPCl ₂ , PCl ₃ , C ₄ H ₉ OPCl ₂ , CH ₃ PCl ₂ ,
C ₄ H ₉ PCl ₂ ; (CH ₃ ) ₃ SiCl, CH ₃ (CH ₃ O) ₂ SiCl,
( _CH3O ) _3SiCl , _CH3O ( _CH3 ) _2SiCl ,
( _CH3 ) _{2SiCl2 ,} ( _CH3O ) _{2SiCl2 , CH3} ( _CH3O )
Examples include _SiCl2 . Among these, more preferable compounds include CH ₃ OPCl ₂ ,

【formula】

[Formula] (CH ₃ ) ₃ SiCl, CH ₃ (CH ₃ O) ₂ SiCl, CH ₃ O (CH ₃ ) ₂ SiCl,
Examples include (CH ₃ O) ₃ SiCl. In addition, carbon halogen compounds such as COCl ₂ and CH ₃ COCl may be used as the reagent. In short, in this invention, the protection of the carboxyl group of the 3-substituted product is carried out to prevent it from participating in the subsequent iminohalide-forming reaction and iminoether-forming reaction, and the type of protecting group is not particularly limited. However, it is desirable to select one from the above in consideration of easy hydrolyzability, cost of reagents, ease of treatment, etc. The reaction that protects this carboxyl group is methylene chloride, ethylene chloride, tetrahydrofuran,
triethylamine, quinoline, pyridine, under anhydrous conditions in an inert organic solvent such as chloroform.
This is done by adding an organic base such as dimethylaniline and their congeners. The above reaction product is then reacted with an iminohalide forming agent such as phosphorus pentachloride, phosphorus oxychloride, or phosgene. This reaction converts the acid amide bonds at the 7- and 5'-positions of the 3-substituted product into iminohalides. Thereafter, lower alcohols such as methanol, propanol, butanol, amyl alcohol, ethylene glycol, propylene glycol, ethylene chlorohydrin, and alkoxyethanol are added to the reaction solution. The iminohalide is thereby converted into an iminoether. In the above two reactions, the reaction solution in which the carboxyl group has been protected is used as it is. The iminoether obtained above is subjected to a hydrolysis reaction with water and is led to the desired 3-substituted-7-aminocephalosporanic acids (). This hydrolysis is carried out in an acidic environment, but it is usually desirable to carry out the hydrolysis at a pH of 3 or less. The reaction solution subjected to hydrolysis was converted into a mixture containing 3-substituted-7 aminocephalosporanic acid ().
By adjusting the isoelectric point of , the desired substance can be obtained as a precipitate. This precipitate is separated and dried according to a conventional method. By the above method, the desired substance can be obtained in extremely high yield and purity. The substituent at the 3-position of the desired substance () obtained here is as explained by way of example for the raw material (). The method of the present invention will be explained below with reference to Examples, but the present invention is not limited thereto. Reference example 1 Approximately 0.2 g of sodium borate was added to 20 ml of "resin eluent" containing 30 mg of cephalosporin C (by UV quantitative method) per ml, adjusted to pH 9.0 with dilute sodium hydroxide solution, and added with pivalic acid chloride. Add 5 ml of an ethyl acetate solution of a mixed acid anhydride made from the N-methylmorpholine salt of methylthioacetic acid (containing 2.5 equivalents per mole of cephalosporin C) and stir vigorously at 0-10°C. The reaction solution is reacted for about 1 hour while adjusting the pH to 9.0 with diluted sodium hydroxide solution. When the reaction ends
TLC (benzene:acetic acid:pyridine:water=15:
3:10:12, the coloring agent is confirmed by heating after spraying the azide iodide solution, and the pH is adjusted to 5 to 6 with dilute sulfuric acid. Remove the organic layer and dilute the aqueous layer to 30 ml. (2% solution in terms of cephalosporin C). To 15 ml of this solution, 0.43 ml of quinoline (5 ml per mole of cephalosporin C)
equivalent amount) and PH with dilute sulfuric acid while stirring at 10℃.
Adjust to 3.0. Crystals will soon begin to precipitate. After stirring for 1 hour,
The crystals were collected, washed with a small amount of ice water, further washed with ethyl acetate, and dried overnight in a vacuum dryer to obtain N-methylthioacetyl-cephalosporin C. IR 17900cm ^-1 (β-lactam), UVλmax264
mμ. 450 mg (97% purity by UV quantitative method). yield
98% Reference Example 2 Take 15 ml of each reaction solution from a 3% solution of cephalosporin C (2% solution in terms of cephalosporin C) carried out according to Example 1, make diluted solutions as shown below, and add 0.43 quinoline to each solution. ml (5 equivalents per mole of cephalosporin C) was added and treated according to Reference Example 1. (The numbers in the box indicate the values after diluting with 5% saline.)

[Table] Example 1 (a) 3.8 g of quinoline adduct of 5'-N-methylthioacetyl-cephalosporin C was suspended in 25 ml of water, adjusted to pH 6.5 with 2N aqueous sodium hydroxide solution, and diluted with methylene chloride. Washed twice. then 1
0.8 g of -methyltetrazole-5-thiol and 0.5 g of acidic sodium phosphate were added, and the pH was adjusted to 6.5 again with sodium hydroxide. This mixture was heated at 60-70°C for 5-8 hours with stirring. (The reaction was followed by thin layer chromatography.) After the reaction was completed, the pH was adjusted to 2.0 with dilute sulfuric acid, extracted several times with ethyl acetate, the organic layer was washed four times with small amounts of saturated saline, and dried over magnesium sulfate. Thereafter, the solvent was distilled off under reduced pressure. The residue is candy-like and solidifies when treated with n-hexane to give 5-[(5′-N-methylthioacetamide)-adipoylamide]-3-
2.3 g of (1″-methyltetrazol-5″-yl)-thiomethyl-3-cephem-4-carboxylic acid
(yield 84%). IR (KBr): 1770cm ^-1 , UVλmax: 272mμ (b) 1.1g of the compound obtained in (a) above was heated over phosphorus pentoxide at 70~
Vacuum drying was performed at 80°C. To this dried product were added 10 ml of dry methylene chloride, 2.4 g of dimethylaniline, and 1.3 g of methyl dichlorophosphite, and the mixture was stirred at room temperature. After 30 minutes, the clear reaction solution was cooled to -30°C, and while stirring, 1.2g of phosphorus pentachloride was added, and the temperature was reduced to -20°C.
The reaction was carried out at ~0°C for 2 hours and cooled again to -40°C. Add 2.6 g of anhydrous methanol dropwise to this, and -20
React at ~-5℃ for 2 hours, then overnight at -20℃
It was left in the cold room. The reaction solution was placed in 7 ml of ice water, stirred for 20 minutes, and then gradually adjusted to pH 3.5 with ammonium carbonate. Leave it in the ice room overnight
After adjusting the pH to 3.5 again, the crystals were grown in a centrifuge. The crystals were washed with 60% cold acetone, centrifuged, washed again with acetone, and 7-amino-3
-(1'-Methyl-tetrazol-5'-yl)-thiomethyl-3-cephem-4-carboxylic acid 0.55
g (yield: 86%). IR: 1800cm ^-1 , UVλmax: 272mμ (c) Using 3.1g of trimethoxysilyl chloride instead of methyldichlorophosphite in (b) above,
The yield was 84% when otherwise the same reagents and treatment method were applied. Furthermore, when only methanol was replaced with isobutanol, the yield was 83%. (d) Using the same reagents and treatment method, except using 1.6 g of acetyl chloride instead of methyl dichlorophosphite and 3.7 g of ethylene glycol instead of methanol, the yield was 76 It was %. Example 2 (a) In place of 1-methyltetrazole-5-thiol in (a) of Example 1, 5-methyl 1.
Using 3,4-thiadiazole-2-thiol and otherwise treating in exactly the same manner, 7-[(5′-N-methylthioacetamide)-adipoylamide]-3
-(5″-methyl-1″・3″・4″-thiadiazol-2″-yl)-thiomethyl-3-cephem-4
-2.4 g of carboxylic acid (yield 84%) was obtained. IR: 1780cm ^-1 , UVλmax: 272mμ (b) Using 1.2g of the product obtained in (a) above, Example 1
(b) to give 7,-amino-3-
(5′-methyl-1′・3′・4′-thiadiazole-
2'-yl)-thiomethyl-3-cephem-4-
0.6 g (yield 87%) of carboxylic acid was obtained. IR: 1800cm ^-1 , UVλmax: 272mμ Example 3 (a) Using 1,3,4-thiadiazole-2-thiol instead of 1-methyltetrazole-5-thiol in (a) of Example 1, the same procedure was carried out. treatment to give 7-[(5'-N-methylthioacetamide)adipoylamide]-3-(1', 3', 4'-thiadiazol-2'-yl)-thiomethyl-3-cephem-4-carvone. 2.3 g (yield 82%) of acid was obtained. IR: 1780 cm ^-1 , UV λmax: 270 mμ (b) Using 1.1 g of the product obtained in (a) above, the process was otherwise carried out in the same manner as in Example 1 (b) to obtain 7-amino-3-
(1', 3', 4'-thiadiazol-2'-yl)-thiomethyl-3-cephem-4-carboxylic acid 0.5
g (yield 83%). IR: 1800cm ^-1 , UVλmax: 270mμ

Claims (1)

[Claims] 1. General formula (In the formula, R ₁ is a lower alkyl group, Y is a sulfur atom or sulfinyl group, and R ₂ is a lower alkylene group.) or general formula
HS-R ₃ (in the formula, R ₃ is a heterocyclic group, which may be substituted with a methyl group) is reacted with a thiol or its salt, and the carboxyl groups at the 4- and 5'-positions of the resulting 3-substituted product are reacted. The carboxyl group is protected by converting it into an easily hydrolyzable ester or mixed acid anhydride, and the iminohalide forming agent is then reacted with a lower aliphatic alcohol to form an iminoether, and the resulting iminoether is hydrated in an acidic region. Decomposed and general formula (wherein X means an azide group or -SR ₃ (R ₃ has the same meaning as above)) - A method for producing aminocephalosporanic acids.