Phosphorus oxychloride → p-Nitrobenzyl 7-{2(2-formamido-4-thiazolyl)-2-methoxyiminoacetamido}-3-chloro-3-cephem-4-carboxylate

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Reaction Steps

N,N-Dimethylformamide (0.16 g.) and phosphorous oxychloride (0.34 g.) were mixed to prepare Vilsmeier reagent in a usual manner, and the resultant Vilsmeier reagent was suspended in dry ethyl acetate. To the suspension was added 2-(2-formamido-4-thiazolyl)-2-methoxyiminoacetic acid (syn isomer, 0.46 g.) under ice-cooling with stirring, and then the solution was stirred at the same temperature for 30 minutes to prepare the activated acid solution. p-Nitrobenzyl 7-amino-3-chloro-3-cephem-4-carboxylate hydrochloride (0.81 g.) was dissolved in a solution of trimethylsilylacetamide (2.10 g.) in ethyl acetate (200 ml.). To the solution was added the activated acid solution obtained above all at once at -20° C., and the solution was stirred at -20°~-5° C. for 1.5 hours. After water and ethyl acetate (100 ml.) were added to the resultant solution at -20° C. the insoluble product was separated by filtration, washed with water and acetone in turn and then dried to give p-nitrobenzyl 7-{2-(2-formamido-4-thiazolyl)-2-methoxyiminoacetamido}-3-chloro-3-cephem-4-carboxylate (syn isomer, 0.6 g.).

Provenance & Evidence