反应详情

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.

1. additionis added dropwise, under ice-
2. temperaturecooling
3. stirringThe mixture is stirred for one hour
4. extractionfollowed by extraction with methylene chloride
5. washThe organic layer is washed with water
6. customdried
7. concentrationconcentrated under reduced pressure
8. customThe residue is purified by means of a silica gel column chromatography (eluent : ethyl acetate-acetone-hexane=2:1:2)