Patent ID: 7507812

Claim:
A process for preparing a 3-chloromethyl-3-cephem derivative comprising the following first to third steps: First step: reacting a thiazoline azetidinone derivative with a sulfonyl halide in a solvent and in the presence of an acid to produce an azetidinone derivative, the thiazoline azetidinone derivative being expressed by Chemical Formula (1): wherein R 1 and R 2 each represent an aromatic hydrocarbon group, sulfonyl halide being expressed by Chemical Formula (2): R 3 —SO 2 X (2) wherein R 3 represents one selected form the group consisting of substituted or unsubstituted aryl groups and substituted or unsubstituted heterocyclic residues, and X represents a halogen atom, and the azetidinone derivative being expressed by Chemical Formula (3): wherein R 1 , R 2 and R 3 are the same as described above; Second Step: reacting the azetidinone derivative obtained by the first step with a chlorination agent in an organic solvent to produce a chlorinated azetidinone derivative, the chlorinated azetidinone derivative being expressed by Chemical Formula (4): wherein R 1 , R 2 and R 3 are the same as described above; and Third Step: reacting the chlorinated azetidinone derivative obtained by the second step with an alcoholate in a solvent containing an alcohol and an ether at a pH of 8 or less to produce a 3-chloromethyl-3-cephem derivative in a crystal form, the alcoholate being expressed by Chemical Formula (5): R 4 —OM (5) wherein R 4 is an organic group and M is an alkali metal atom, and the 3-chloromethyl-3-cephem derivative being expressed by Chemical Formula (6): wherein R 1 , R 2 and R 3 are the same as described above.