diphenylmethyl (6R,7R)-7-Amino-8-oxo-5-thia-1-azabicyclo(4.2.0)oct-2-ene-2-carboxylate → 7beta-[2-Methoxyimino-2-(2-chloroacetamido-5-chloro-4-thiazolyl)acetamido]-3-cephem-4-carboxylic acid diphenylmethyl ester

Participants

Reaction Steps

To a solution of 7β-amino-3-cephem-4-carboxylic acid diphenylmethyl ester (1.10 g) in dichloromethane (120 ml) are added a solution of 2-(2-chloroacetamido-5-chloro-4-thiazolyl)-2-methoxyiminoacetic acid (1.20 g) and N,N-dicyclohexylcarbodiimide (0.80 g), and the mixture is stirred for 30 minutes at room temperature. After concentrating to remove dichloromethane, the obtained residue is treated with a small amount of ethyl acetate and filtered to remove insoluble material. The solution is concentrated in vacuo, and the residue is purified by chromatography on silica gel affording 7β-[2-methoxyimino-2-(2-chloroacetamido-5-chloro-4-thiazolyl)acetamido]-3-cephem-4-carboxylic acid diphenylmethyl ester (1.49 g). mp. 149°-151° C. when crystallized from benzene. Similarly prepared are compounds of Table 1.

Provenance & Evidence