反应详情

To a solution of 7β-[2-methoxyimino-2-(2-chloroacetamido-5-chloro-4-thiazolyl)acetamido]-3-cephem-4-carboxylic acid diphenylmethyl ester (330 mg) in a mixture of ethanol (5 ml) and tetrahydrofuran (5 ml) is added thiourea (152 mg), and the mixture is stirred for 4 hours. After one night, the solution is stirred with 5% aqueous sodium hydrogen carbonate solution for 10 minutes, concentrated to remove organic solvents, and extracted with ethyl acetate. The residue is subjected to silica gel chromatography to give crude 7β-[2-methoxyimino-2-(2-amino-5-chloro-4-thiazolyl)acetamido]-3-cephem-4-carboxylic acid diphenylmethyl ester (273 mg), which is stirred with anisole (0.5 ml) and trifluoroacetic acid (0.5 ml) in dichloromethane (5 ml) under ice-cooling for 1.5 hours, evaporated and treated with ethyl ether and high porous polymer to give 7β-[2-methoxyimino-2-(2-amino-5-chloro-4-thiazolyl)acetamido]-3-cephem-4-carboxylic acid (164 mg). Yield: 76.7%. This product is identical with a sample prepared by another authentic route. Similarly prepared are compounds of Table 1.

1. waitAfter one night
2. concentrationconcentrated
3. customto remove organic solvents
4. extractionextracted with ethyl acetate
5. customto give crude 7β-[2-methoxyimino-2-(2-amino-5-chloro-4-thiazolyl)acetamido]-3-cephem-4-carboxylic acid diphenylmethyl ester (273 mg), which
6. temperaturecooling for 1.5 hours
7. customevaporated
8. additiontreated with ethyl ether and high porous polymer