Novel azetidine derivatives of the formula IMAGE I wherein R1 is an acylamido group, R2 is selected from the group consisting of IMAGE IMAGE IMAGE IMAGE IIA IIB IIC IID wherein R4, R5 and R6 are individually selected from the group consisting of hydrogen, lower alkyl and lower alkenyl, n is 2 or 3 and - in the case when formula IIB is a phenyl - this group may carry one to four substituents selected from the group consisting of halogen, lower alkyl, lower alkenyl and phenyl, and R3 is lower alkyl optionally substituted with 1 or 2 phenyls which phenyl groups may be substituted with nitro and the dotted lines of formula IIB indicate the optional presence of double bonds and a process for their preparation and process for the preparation of cephalosporanic acid derivatives using the azetidines of formula I as intermediates.
展开▼
