2-Methylamino-5-nitrobenzophenone → Nimetazepam

Participants

Reaction Conditions

Reaction Steps

2-Milliliters of 2-isocyanatoacetyl chloride was cooled, and 0.20 g. of powdered 2-methylamino-5-nitrobenzophenone was added thereto with stirring. After stirring the resulting mixture at room temperature for one hour, excess 2-isocyanatoacetyl chloride was removed by reduced pressure distillation. To the residue was added 4 ml. of pyridine, whereby a reaction took place with generation of heat. The reaction liquid was heated at 95° C, for 1.5 hours, diluted with water and then extracted with chloroform. The chloroform layer was washed with a 5% aqueous hydrochloric acid solution and then with an aqueous sodium chloride solution in this order, dried over Glauber's salt, and evaporated by reduced pressure distillation. Subsequently, the residue was chromatographically purified (solvent: chloroform→ethyl acetate) by use of a column packed with 10 g. of silica gel to obtain 1-methyl-5-phenyl-7-nitro-1,3-dihydro-2H-1,4-benzodiazepin-2-one having a melting point of 154° to 156° C.

Provenance & Evidence