Dimethylformamide → 5-Chloro-3-phenylisoindole-1-carboxylic acid [3-(2-methyl-1,3-dioxolan-2-yl)-propyl]amide

Participants

Reaction Conditions

Reaction Steps

A solution of 40.0 g. of 7-chloro-1,3-dihydro-1-[3-(2-methyl-1,3-dioxolan-2-yl)-propyl]-5-phenyl-2H-1,4-benzodiazepin-2-one in 500 ml. of dimethylformamide is treated under an atmosphere of argon at room temperature with 0.115 mol. of sodium hydride (5.1 g. of a 55% dispersion in mineral oil). The mixture is warmed to 60° C. over a period of about 30 minutes, then stirred at this temperature for 1 hour and thereafter at 70° C. for an additional hour. After cooling, 10 ml. of water are added dropwise and the mixture is poured on to 4 liters of ice-water. After the addition of 150 g. of sodium chloride, the separated product is removed by filtration, washed with water and dissolved in methylene chloride. The organic solution is dried over sodium sulfate and concentrated to dryness. The residue is chromatographed on 1000 g. of silica gel using methylene chloride/ethyl acetate (4:1) for the elution. The homogeneous fractions are combined and evaporated. The residual oil crystallizes upon trituration with hexane, and there is obtained 5-chloro-3-phenylisoindole-1-carboxylic acid [3-(2-methyl-1,3-dioxolan-2-yl)propyl]amide in the form of yellowish crystals having a melting point of 157°-159° C. Recrystallization from ethanol does not increase the melting point.

Provenance & Evidence