Water → 1,3-Bis[4-(4-bromobenzoyl)-1-piperazinyl]propane

Participants

Reaction Conditions

Reaction Steps

To a suspension of 66.7 g (0.218 mmol) of the 1-(4-bromobenzoyl)piperazine hydrochloride prepared in Preparation Example 1 in dimethylformamide (223 mL) were added 11.3 mL (98% purity, 0.109 mmol) of 1,3-dibromopropane and 33.5 g (0.316 mmol) of sodium carbonate. The mixture was stirred for 6 hours at 80° C. Water (670 mL) was added to the reaction mixture with stirring at 80° C. and the mixture was stirred for 0.5 hour at the same temperature and for 1.5 hours at 20° C. The precipitates were collected by filtration and washed with water (3×45 mL) to obtain crude crystals. A suspension of the crude crystals in water-isopropanol (7:3, 570 mL) was stirred for 2 hours at 85° C., for 0.5 hour at room temperature, and for 1 hour at 0° C. Precipitated crystals were collected by filtration and washed with water-isopropanol (5:1, 2×110 mL), whereby 60.0 g of 1,3-bis[4-(4-bromobenzoyl)-1-piperazinyl]propane was obtained as colorless fine needles (yield 95%).mp: 170.0 to 173.0° C.

Provenance & Evidence