Novel 1β-methylcarbapenems with isoxazoloethenyl moieties containing carboxylic acid sodium salt

The synthesis of novel 1β-methylcarbapenems 1a,b having sodium 5-(3- and 5-carboxylic acid)isoxazoloethenyl moieties at C-5 position of pyrrolidine ring and their biological evaluation are described. Both compounds showed potent and well-balanced antibacterial activity as well as high stability to DHP-I. The selected sodium 3-carboxylic acid derivative 1a possessed excellent DHP-I stability and advanced pharmacokinetic parameters in comparison with 2 and meropenem.