PROCESS FOR THE PREPARATION OF 7-(SUBSTITUTED)AMINO-3-SUBSTITUTED THIOMETHYL-DELTA3-CEPHEM-4-CARBOXYLIC ACIDS

摘要

Prepn. of 3-thiomethyl-3-cephem cpds. of formula (I) is carried out by reacting a cpd. of formula (II) with a thiol cpd. of formula R8SM (III) in an organic solvent in the presence of a protonic or Lewis acid or a Lewis acid complex, with the exception of BF3 and its complexes. In the formulae, R1 is H or 1-4C alkoxy; R2 is NH2, NH-C(R5)=CR3R4 or N=CR6R7; R3-R7 are H or inert organic gps.; R8 is the residue of a thiol cpd., pref. an N-heterocyclic gp.; Q is COOH or a deriv. or salt thereof; X is opt. substd. acyloxy or carbamoyloxy; Y is S or SO. (I) are useful as intermediates for cephalosporin analogues. The process gives high yields (e.g. >80%) and is suitable for operation on an industrial scale.