Stable oxapenem-3-carboxylic acids

Abstract From the Canadian patent

Compounds of the structural formulae, (see fig.I) or (see fig.II) and their pharmaceutically acceptable salts esters and, amide derivatives, in which R1 and R2 independently of, one another, denote hydrogen or pharmaceutically acceptable groups which have 1 to 10 carbon atoms and are bonded to the remaining part of the molecule via carbon-carbon single bonds, and in which R3, R4 and R5 independently, of one another, denote pharmaceutically acceptable groups which have 1 to 10 carbon atoms and are bonded to the remaining part of the molecule via carbon-carbon single bonds, are useful antibiotics. The trisubstitution by three groups R3 R4 and, R5, which are bonded via carbon-carbon single …