PROCESS FOR PRODUCING NEW INTERMEDIATES OF PENAME-3-CARBOXYLIC ACID AND CEPHEME-4-CARBOXYLIC-ACID DERIVATIVES

摘要

There is described a process for preparing a sulphoxide of the formula (I) in which R1, R2, R3 and R4, taken individually, are alkyl, alkoxy or aryl groups, X is an alkylene group, R5 is a carboxylic acid protecting group and Y is a linking group through one or two carbon atoms forming a penam or cephem nucleus, which comprises reacting a compound of formula (II) with an oxidizing agent. alpha -Sulphoxide compounds of formula (I) are also provided as novel intermediates.