BO-2502A

The synthesis and biological activity of (1R,5S,6S)-2-[(3S,5S)-5-substituted pyrrolidin-3-ylthio]-6-[(R)-1-hydroxyethyl]-1-methyl-1-ca rbapen-2-em-3- carboxylic acid, in which lactams and cyclic amines are introduced as substituents, are described. They showed potent antibacterial activity against Gram-positive and Gram-negative bacteria including P. aeruginosa. Among them, BO-2502A (4h-1) was selected for further evaluation.