Penicillins and their preparation

摘要

Carbamic acid lactones of the formula <IMAGE> wherein Y is H or alkyl of 1-4 carbon atoms and R2 and R3 each are H or collectively with the carbon atoms to which they are attached form a first benzene or pyridine ring which is unsubstituted, substituted by up to two of alkyl, alkoxy of 1-4 carbon atoms, dialkylamino or halogen, wherein alkyl and alkoxy in each instance are of 1-4 carbon atoms, or is fused at two adjacent carbons to a second benzene or pyridine ring, are useful as intermediates for the production of penicillins by reaction with a penicillin of the formula <IMAGE>