Process for production of intermediates for use in cefalosporin synthesis

A process for the production of intermediates having a formula IA that can be used for the synthesis of cephalosporins, such as cefepime of formula V. The intermediates of formula IA are produced by desilyation of a compound of formula II wherein R4 is a silyl-protecting group, with a protic solvent to obtain a compound of formula III, and reacting the compound of formula III with an organic base of formula IV wherein R2 and R3 together represent a C4-alkylene group, and with the adjacent nitrogen atom form a saturated 5-membered heterocycle, and R1 represents a methyl group, to obtain the compound of formula 1A.