Triethylamine → 1-(3-Coumarinylcarbonyl)-4-(3,4,5-trimethoxybenzyl)piperazine

Participants

Reaction Steps

To a mixture of coumarin-3-carboxylic acid (0.9 g), 1(3,4,5-trimethoxybenzyl)piperazine dihydrochloride (1.7 g), triethylamine (1.8 g) and N,N-dimethylformamide (20 ml) is added dropwise at room temperature diethyl cyanophosphonate (1.8 ml), followed by stirring for one hour. After addition of water (50 ml), the reaction mixture is left standing for 30 minutes, followed by addition of water (150 ml), ethyl acetate (200 ml) and hexane (50 ml). The mixture is vigorously mixed and the organic layer is separated. The organic layer is washed with water, dried, and concentrated under reduced pressure. The residue is purified by means of a silica gel column chromatography(hexane:acetone=1:1-1:2) to give an oily product, which is crystallized from a mixture of acetone and ethyl ether to afford 1-(3-coumarinylcarbonyl)-4-(3,4,5-trimethoxybenzyl)piperazine (0.35 g) as colorless needles, m.p. 171°-173° C.

Provenance & Evidence