Pyridine → 1-methyl-7-chloro-3-dipropylacetoxy-5-phenyl-1,3-dihydro-2H-1,4-benzodiazepine-2-one

Participants

Reaction Steps

A solution of 15 g of 1-methyl-7-chloro-3-hydroxy-5-phenyl-1,3-dihydro-2H-1,4-benzodiazepine-2-one (Temazepam) and 5 g of absolute pyridine is cooled in 40 ml of freshly distilled dimethyl formamide to -5° and is mixed drop by drop with 10.5 g of dipropyl acetic acid chloride with the exclusion of atmospheric moisture. The mixture is stirred for an additional 4 hours at -5° and is allowed to stand over night at 0°, and then the mixture is poured on ice. The separated oil crystallizes while rubbed on with ethanol. By recrystallization from petroleum ether or isopropanol using activated charcoal, one will obtain the 1-methyl-7-chloro-3-dipropylacetoxy-5-phenyl-1,3-dihydro-2H-1,4-benzodiazepine-2-one as a colorless powder with a melting point of 134°-136°.

Provenance & Evidence