Phosphorus oxychloride → Benzhydryl 7-[4-bromo-2-(2,2,2-trichloroethoxycarbonylmethoxyimino)-3-oxobutyramido]-3-vinyl-3-cephem-4-carboxylate

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

Vilsmeier reagent prepared from phosphorus oxychloride (7.1 ml) and N,N-dimethylformamide (6.0 ml) was suspended in dry tetrahydrofuran (25 ml). To this suspension was added 4-bromo-2-(2,2,2-trichloroethoxycarbonylmethoxyimino)-3-oxobutyric acid (25 g), and the mixture was stirred at 5° C. for an hour to prepare the activated acid solution. This solution was added at a time to a solution of benzhydryl 7-amino-3-vinyl-3-cephem-4-carboxylate hydrochloride (16.2 g) and trimethylsilylacetamide (40 g) in ethyl acetate (140 ml) at -30° C., and the mixture was stirred at -15° to -5° C. for an hour. The reaction mixture was extracted with ethyl acetate, and the extract was washed with a saturated aqueous sodium bicarbonate and a saturated aqueous sodium chloride, followed by drying over magnesium sulfate. Removal of the solvent gave benzhydryl 7-[4-bromo-2-(2,2,2-trichloroethoxycarbonylmethoxyimino)-3-oxobutyramido]-3-vinyl-3-cephem-4-carboxylate (26.0 g).

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