反应详情

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.

1. concentrationAfter concentrating
2. customto remove dichloromethane
3. additionthe obtained residue is treated with a small amount of ethyl acetate
4. filtrationfiltered
5. customto remove insoluble material
6. concentrationThe solution is concentrated in vacuo
7. customthe residue is purified by chromatography on silica gel