Phosphorus oxychloride → HCID 131713533, compound

Participants

Reaction Steps

Vilsmeier reagent prepared from phosphorus oxychloride (0.67 ml) and N,N-dimethylformamide (0.57 ml) was suspended in dry tetrahydrofuran (24 ml). To the suspension was added 2-(2-formamidothiazol-4-yl)-2-tert-butoxycarbonylmethoxyiminoacetic acid (syn isomer) (2.4 g) at 0° to 5° C. The solution was stirred at the same temperature for an hour to prepare the activated acid solution. To a solution of benzhydryl 7-amino-3-tosyloxy-3-cephem-4-carboxylate (3.0 g) and monotrimethylsilylacetamide (5.8 g) in methylene chloride (30 ml) was added the activated acid solution obtained above at -20° C. all at once. The reaction mixture was stirred at -10° C. for an hour. The resulting solution was poured into water (100 ml) and extracted with ethyl acetate (100 ml). The separated organic layer was washed with a saturated aqueous solution of sodium bicarbonate, and with a saturated aqueous solution of sodium chloride. The organic layer was dried over magnesium sulfate and concentrated under reduced pressure to give benzhydryl 7-[2-(2-formamidothiazol-4-yl)-2-tert-butoxycarbonylmethoxyiminoacetamido]-3-tosyloxy-3-cephem-4-carboxylate (syn isomer) (3.4 g).

Provenance & Evidence