Trimethyl phosphite → 3-Fluoro-1,3-dihydro-1-methyl-7-chloro-5-phenyl-2H-1,4-benzodiazepin-2-one

Participants

Reaction Steps

A solution of 15.93 g (0.05 mole) of 7-chloro-3-fluoro-1,3-dihydro-1-methyl-5-phenyl-2H-1,4-benzodiazepin-2-one 4-oxide and 20 ml (0.16 mole) of trimethyl phosphite in 250 ml of methylene chloride was allowed to remain at room temperature (about 25° C.) for 3 days, and then evaporated to dryness under reduced pressure. The residue was suspended in water, collected on a filter, washed thoroughly with water, and dried in air to give 14.91 g (98.5% yield) of crude 7-chloro-3-fluoro-1,3-dihydro-1-methyl-5-phenyl-2H-1,4-benzodiazepin-2-one as a white powder. Analysis by high pressure liquid chromatography indicated the product was 98.9% pure. Recrystallization from ethanol gave colorless crystals: mp 145°-147°; 19F nmr (CDCl3) δ -161.7 ppm (d, J=57 Hz); 1H nmr (CDCl3) δ 3.43 ppm (s, 3H), 5.54 ppm (d, J=57 Hz, 1H) and 7.5 ppm (m, 8H).

Provenance & Evidence