Asahi Kasei Kogyo Kabushiki Kaisha

Kunihiko Ishii

Chisei Shibuya

Mitsuru Shibukawa

Torao Ishida

Hirataka Itoh

Takumi Sano

A secalonic acid derivative of the formula (I); ##STR1## wherein R is ##STR2## wherein R.sub.1 and R.sub.2 each independently is a hydrogen atom or a C.sub.1-4 alkyl group; R.sub.3 is a hydrogen atom, a C.sub.1-4 alkyl group, and aryl group, a C.sub.1-5 alkoxy group, a halogen atom, a cyano group, a carboxyl group, a sulfonic acid group, a carboxylic acid amide group or a sulfonic acid amide group; and R.sub.4 is a saturated or unsaturated C.sub.1-22 alkyl group, an aryl group or an aryl alkyl group, and may have a substituent; and the pharmaceutically acceptable salts thereof.

Secalonic acid derivatives as antitumor agents

A secalonic acid derivative of the formula (I); ##STR1## wherein R is ##STR2## wherein R.sub.1 and R.sub.2 each independently is a hydrogen atom or a C.sub.1-4 alkyl group; R.sub.3 is a hydrogen atom, a C.sub.1-4 alkyl group, an aryl group, a C.sub.1-5 alkoxy group, a halogen atom, a cyano group, a carboxyl group, a sulfonic acid group, a carboxylic acid amide group or a sulfonic acid amide group; and R.sub.4 is a saturated or unsaturated C.sub.1-22 alkyl group, an aryl group or an aryl alkyl group, and may have a substituent; and the pharmaceutically acceptable salts thereof.

Secalonic acid derivatives and method for preparing thereof

An 1,3,4-thiadiazole-5-thiol ester of the formula, ##STR1## wherein R is a hydrogen atom or a methyl group, a process for their preparation and a process for preparing a cephalosporin compound of the formula, ##STR2## wherein R is the same as defined above, using the above described 1,3,4-thiadiazole-5-thiol ester.

Novel thiol esters and process for preparing cephalosporin compounds

Novel 7.alpha.-methoxycephalosporin derivatives having a high antimicrobial activity. They are useful for the medical treatment of diseases infected by gram-positive bacteria and gram-negative bacteria. More particularly, they show an antimicrobial activity against bacteria such as Eschericha coli Proteus, Citrobacter and Enterobacter which bacteria have resistance to the conventionally employed cephalosporins, and they are effective for the medical treatment of diseases infected by these bacteria. Such 7.alpha.-methoxycephalosporin derivatives are prepared by a relatively simple method.

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Fuji, Japan

Kunihiko Ishii