SYNTHESES AND ANTIBACTERIAL ACTIVITIES OF PENICILLINS FROM (+)- AND (-)-a-AMINO- 4-ISOTHIAZOLYLACETIC ACIDS
作者:R. RAAP
DOI:10.7164/antibiotics.24.695
日期:——
α-Amino-4-isothiazolylacetic acid has been prepared by reaction of α-bromo-4-isothiazalylacetic acid with ammonium hydroxide and by catalytic hydrogenation of α-azido-4-isothiazolylacetic acid. The α-azido acid has been resolved into its two optical isomers from which the optically active amino acids were prepared. The absolute configurations of these amino acids are tentatively assigned. The dextrorotatory isomer can also be prepared directly by resolution of the racemic amino acid with d-camphor-10-sulfonic acid. From the optically active amino acids the penicillins were synthesized by the activated ester method using the p-nitrocarbobenzoxy protecting group. Some MIC and CD50 values against Gram-positive and Gram-negative bacteria are given. The introduction of an α-amino group into 4-isothiazolylmethylpenicillin produces only a minimal effect in the Gram-negative activity.