Water → 7beta-Phenoxyacetamido-3-hydroxy-3-cephem-4-carboxylic acid p-nitrobenzyl ester

Participants

Reaction Steps

A solution of 160 mg (0.23 mmol) of a mixture consisting of 2-[4-(p-toluenesulphonylthio)-3-phenoxyacetamido-2-oxoazetidin-1-yl]-3-(1-pyrrolidyl)-crotonic acid p-nitrobenzyl ester and the corresponding isocrotonic acid ester in 3 ml of dry acetonitrile is heated under nitrogen for about 4 hours at 80° C. until no further starting material can be detected by thin layer chromatography (silica gel; toluene/ethyl acetate, 1:1). The heating bath is removed, p-toluenesulphonic acid (about 0.23 mmol) and 0.2 ml of water are added to the reaction mixture containing the 7β-phenoxyacetamido-3-pyrrolidino-cephem-4-carboxylic acid p-nitrobenzyl ester and the mixture is stirred for a further 2 hours at room temperature. The reaction mixture is diluted with benzene, washed with water, dried over sodium sulphate and evaporated in vacuo. The residue is triturated at 0° C. with diethyl ether and gives the pale yellow 7β-phenoxyacetamido-3-hydroxy-3-cephem-4-carboxylic acid p-nitrobenzyl ester.

Provenance & Evidence