beta -Lactam antibiotics, a process for their prepaeration and their use in pharmaceutical compositions

摘要

The present invention provides the antibacterial agents of the formula (II): <IMAGE> wherein R1 is a group such that CO2R1 is a carboxylic acid group or a salt thereof or is a group of the formula CO2R11 wherein R11 is a group such that CO2R11 is an ester group, R2 is a hydrogen atom or a lower alkyl group; R3 is a hydrogen atom or a lower alkyl group; and R4 is a NH. COnR6 group where R6 is a lower alkyl group, a phenyl group or a phenyl group substituted by one or two halogen atoms, lower alkyl or lower alkoxyl groups; and n is 1 or 2. A process for their preparation and their use in pharmaceutical compositions is also described.