3,4,5-Trimethoxybenzoic Acid → 1-(2,3-dimethoxy-6,7-dihydro-5H-benzocyclohepten-8-ylcarbonyl)-4-(3,4,5-trimethoxybenzoyl)piperazine

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Reaction Steps

To a mixture of 1-(2,3-dimethoxy-6,7-dihydro-5H-benzocyclohepten-8-ylcarbonyl)piperazine (0.8 g), 3,4,5-trimethoxy benzoic acid (0.55 g), triethylamine (0.4 g) and N,N-dimethylformamide (10 ml) is added dropwise diethyl phosphorocyanidate (0.5 g) with stirring under ice-cooling. The reaction mixture is stirred for one hour at room temperature. To the reaction mixture are added water (60 ml) and ethyl acetate (50 ml), followed by shaking. The organic layer is separated, washed with water, dried and concentrated under reduced pressure. The residue is purified by silica gel column chromatography (eluent, ethyl acetate:hexane:acetone=10:5:8) to afford 1-(2,3-dimethoxy-6,7-dihydro-5H-benzocyclohepten-8-ylcarbonyl)-4-(3,4,5-trimethoxybenzoyl)piperazine (1.1 g). This product is in agreement with the compound obtained by Example 62 in physico-chemical constants.

Provenance & Evidence