反应详情

温度

0 °C

3 ml of an ethereal diazomethane solution (0.5 molar, 1.5 equivalents) are added in the course of about 10 minutes to a solution, cooled to 0° C., of 485 mg of 7β-phenoxyacetamido-3-hydroxy-3-cephem-4-carboxylic acid p-nitrobenzyl ester in 10 ml of dry chloroform. The pale yellow solution is stirred for 1 hour at 0° C., flushed with nitrogen in order to remove excess diazomethane and concentrated in vacuo. The residue is recrystallised from methylene chloride and gives 7β-phenoxyacetamido-3-methoxy-3-cephem-4-carboxylic acid p-nitrobenzyl ester of melting point 140.5°-142° C.

1. customflushed with nitrogen in order
2. customto remove excess diazomethane
3. concentrationconcentrated in vacuo
4. customThe residue is recrystallised from methylene chloride