Takeda Chemical Industries, Inc.

Koji Nishijima

Hiroshi Akimoto

Tadashi Hanaoka

Nobuharu Kakeya

Keiichi Sugimoto

Novel penicillins of the formula ##STR1## wherein R is a branched chain alkyl group of from 3 to 14 carbon atoms, and their pharmaceutically acceptable salts, are easily absorbed in the blood and tissues through oral administration and show excellent antimicrobial activity against Gram-positive and Gram-negative bacteria, particularly against microorganisms of the genus Pseudomonas, such as Pseudomonas aeruginosa.

.alpha.-Alkylsulfobenzyl penicillins

Novel d-.alpha.-isobutylsulfobenzylpenicillin hemi-solvate crystals of the formula: ##STR1## (wherein A is a solvent selected from the class consisting of alcohols, ketones, ethers and esters) have excellent antibacterial activities and improved stability in terms of shelf-life.

d-.alpha.-Isobutylsulfobenzylpenicillin hemi-solvate crystals

.alpha.-Sulfophenylacetic acid derivatives of the general formula: ##STR1## (wherein R is a substituted or unsubstituted primary alcohol, cyclic alcohol or phenol compound residue), which are of value as intermediates of antibacterial agents, are selectively produced in a high yield by bringing a diester compound of the general formula: ##STR2## (wherein R has the same meaning as defined above) into contact with a strong acid.

Process for producing alpha-sulfophenylacetic acid derivatives

.alpha.-Sulfophenylacetic acid derivatives of the general formula: ##EQU1## (wherein R is a substituted or unsubsituted primary alcohol, cyclic alcohol or phenol compound residue), which are of value as intermediates of antibacterial agents, are selectively produced in a high yield by bringing a diester compound of the general formula: ##EQU2## (wherein R has the same meaning as defined above) into contact with a strong acid.

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Osaka, Japan

Koji Nishijima