PHOSPHORUS CONTAINING COMPOUNDS USED IN THE PREPARATION OF CEPHALOSPORINS

摘要

There is described a process for preparing an enamine of formula (IX): where R<2> is a carboxylic acid protecting group and R<3> is the residue of a carboxylic acid derived acyl group and where R<5> and R<6> are the same or different C1-4 alkyl or C1-10 aralkyl groups; or taken together with the adjacent nitrogen atom form a heterocyclic ring containing from 4 to 8 carbon atoms and optionally a further heteroatom selected from oxygen and nitrogen; by reacting a compound of formula (XII): with an amine of formula HNR<5>R<6>, the reactant of formula (XII) being prepared by reaction of an appropriate enol derivative with a phosphorus reagent. The enamines of formula (IX) are useful in the preparation of 3- hydroxycephalosporins. The compounds of formula (XII) are novel.