Triethylamine → 7beta-Phenoxyacetylamino-3-methanesulphonyloxy-2-cephem-4-carboxylic acid diphenylmethyl ester

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Reaction Steps

A solution of 50.6 g (98 mmols) of 7β-phenoxyacetylamino-3-hydroxy-3-cephem-4-carboxylic acid diphenylmethyl ester in 500 ml of methylene chloride is cooled to -20° C. and, after adding 14 ml of methanesulphonyl chloride (142 mmols), 22.3 ml (142 mmols) of triethylamine are added slowly. After a reaction period of 1 hour at -15° C. to -20° C. under nitrogen, the solution is washed with water, aqueous sodium bicarbonate solution and saturated aqueous sodium chloride solution. The organic phase is dried over sodium sulphate, concentrated in a rotary evaporator and dried under a high vacuum. A mixture consisting of 7β-phenoxyacetylamino-3-methanesulphonyloxy-3-cephem-4-carboxylic acid diphenylmethyl ester and 7β-phenoxyacetylamino-3-methanesulphonyloxy-2-cephem-4-carboxylic acid diphenylmethyl ester is obtained; thin layer chromatogram (silica gel; toluene/ethyl acetate, 2:1), 3-cephem derivative Rf=0.39; 2-cephem derivative Rf=0.32.

Provenance & Evidence