Studies on penem and carbapenem. II. An improved synthesis of orally active penem antibiotic (5-methyl-2-oxo-1,3-dioxol-4-yl)methyl (5R, 6S)-2-(2-fluoroethylthio)-6-((1R)-1-hydroxyethyl)penem-3-carboxylate.
Studies on penem and carbapenem. I. Syntheses and oral absorption of ester-type prodrugs of sodium (5R, 6S)-2-(2-fluoroethylthio)-6-((1R)-1-hydroxyethyl)penem-3-carboxylate.
Acyloxyalkyl esters (2a-d), alkyloxycarbonyloxyalkyl esters (2e-g) and (5-methyl-2-oxo-1,3-dioxol-4-yl)methyl ester (2h) of (5R,6S)-2-(2-fluoroethylthio)-6-[(1R)-1-hydroxyethyl]penem-3- carboxylic acid (1) were synthesized. Enhancedoral absorption was observed in mice reflecting increased lipophilicity, compared with the parent 1 itself. Among them, the ester 2h showed a prolonged plasma level and