Crystalline penem, its production and use.

摘要

A process for producing crystalline acetoxymethyl ester of (+)-(5R,6S)-6- [(R)-1-hydroxyethyl]-3-(3-pyridyl)-7-oxo-4-thia-1-azabicyclo[3.2.0]hep t-2-ene-2-carboxylic acid by adding a poor solvent to a solution of acetoxymethyl ester of (+)-(5R,6S)-6-[(R)-1-hydroxyethyl]-3-(3-pyridyl)-7-oxo-4-thia-1-azabic yclo[3.2.0]hept-2-ene-2-carboxylic acid in a good solvent is disclosed. The crystalline penem compound is useful as an antibacterial agent.