Triethylamine → Ethyl 4-(3,4,5-trimethoxybenzoyl)piperazine-2-carboxylate

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Reaction Steps

To a mixture of ethyl piperazine-2-carboxylate dihydrochloride (2.0 g), triethylamine (1.2 ml) and dichloromethane (40 ml) is added dropwise, under ice-cooling while stirring, a solution of 3,4,5-trimethoxybenzoyl chloride (1.85 g) in dichloromethane (25 ml). The mixture is stirred for one hour, then the reaction mixture is poured into ice-water, followed by extraction with methylene chloride. 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 (eluent : ethyl acetate-acetone-hexane=2:1:2) to afford ethyl 4-(3,4,5-trimethoxybenzoyl)piperazine-2-carboxylate (2.5 g). This product is recrystallized from ethyl acetatehexane to give colorless crystals, m.p. 114-115° C.

Provenance & Evidence