FOERFARANDE FOER FRAMSTAELLNING AV DERIVAT AV KEFALOSPORIN

PURPOSE:Various kinds of conditions such as the kind of ester, solvent or acid acceptor, are selected to effect the direct acyl interchange reaction of the starting compound to produce the titled compound used as an antibiotic with industrial advantage. CONSTITUTION:A compound of formulaI[R1 is acylamide R2 is lower alkyl R3 is heteroring (1H-tetrazol-5-yl group)] is made to react with both a compound of formula II (R is lower alkyl) and the third compound of R5-X(R is acyl X is halogen) in a halogenated hydrocarbon solvent containing more than 1 equivalent amount of water based on the compound of formulaI. The reaction product is treated with an acid such as hydrochloric acid to eliminate ester to give the objective compound of formula III. This process enables the continuous interchange of groups in the 3 and 7 positions of cephamycin obtained by the cultivation of a microorganism and is very useful in industry.