| abstract |
There is described a process for preparing a sulphoxide of the formulan in which R 1 , R 2 , R 3 and R 4 , taken individually, are alkyl, alkoxy or aryl groups, X is an alkylene group, R 5 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 formulan with an oxidising agent. a-Sulphoxide compounds of formula (I) are also provided as novel intermediates. |