Crystalline esters of (+)-(5R, 6S)-6-[(R)-1-hydroxyethyl]-3-(3-pyridyl)-7-oxo-4-thia-1-azabicyclo[3.2.0]hept-2-ene-2-carboxylic acid

摘要

Crystalline acetoxymethyl and pivaloyloxymethyl esters of (+)-(5R, 6S)-6-[(R)-1-hydroxyethyl]-3-(3-pyridyl)-7-oxo-4-thia-1-azabicyclo-[3.2.0]hept-2-ene-carboxylic acid can be obtained by adding a poor solvent to a solution of acetoxymethyl or pivaloyloxymethyl ester of (+)-(5R, 6S)-6-[(R)-1-hydroxyethyl]-3-(3-pyridyl)-7-oxo-4-thia-1-azabicyclo-[3.2.0]hept-2-ene-carboxylic acid in a good solvent. The crystalline penem compounds obtained show improved stability and are useful antibacterial agents.