Phosphorus oxychloride → Chloro-N,N-dimethylformiminium chloride

Participants

Reaction Steps

Vilsmeier reagent was prepared from phosphorus oxychloride (1.3 g) and dimethylformamide (0.6 g) in ethyl acetate (2.4 ml) in a usual manner. 2-(t-Butoxycarbonylmethoxyimino)-2-(4-thiazolyl)acetic acid (syn isomer) (2.0 g) was added to the stirred suspension of Vilsmeier reagent in ethyl acetate (20 ml) under ice cooling and stirred for 20 minutes at same temperature to produced an activated solution. N-(trimethylsilyl)acetamide (5.8 g) was added to the stirred suspension of benzhydryl 7-amino-3-methylthio-3-cephem-4-carboxylate hydrochloride (2.9 g) in ethyl acetate (30 ml) and stirred for 10 minutes at 40° C. To the solution was added the above activated solution at -10° C. and stirred for 30 minutes at same temperature. Water was added to the reaction mixture and separated organic layer was washed with saturated aqueous sodium bicarbonate and saturated aqueous sodium chloride and then dried over magnesium sulfate. The solvent was evaporated to give benzyhydryl 7-[2-(t-butoxycarbonylmethoxyimino)-2-(4-thiazolyl)acetamido]-3-methylthio-3 -cephem-4-carboxylate (syn isomer) (3.62 g).

Provenance & Evidence