反应详情

A solution of 2,3-dimethoxy-6,7-dihydro-5H-benzocycloheptene-8-carbonylchloride (1.1 g) in dichloromethane (12 ml) is added dropwise, taking 30 minutes while stirring under ice-cooling, to a mixture of ethyl piperazine-2-carboxylate hydrochloride (1.0 g), triethylamine (0.5 g) and dichloromethane (20 ml). The reaction mixture is stirred for one hour at 0 ° C, and then poured into ice-water, followed by extraction with dichloromethane. The organic layer is washed with water and dried, then the solvent is distilled off under reduced pressure. The residue is purified by means of a silica gel column chromatography (hexane:ethyl acetate:acetone=1:1:1) to afford ethyl 4-(2,3-dimethoxy-6,7-dihydro-5H-benzocyclohepten-8-ylcarbonyl)piperazine-2-carboxylate as crystals (1.2 g). This product is recrystallized form ethyl acetate and hexane to give colorless prisms, m.p. 105-106° C.

1. stirringThe reaction mixture is stirred for one hour at 0 ° C
2. extractionfollowed by extraction with dichloromethane
3. washThe organic layer is washed with water
4. customdried
5. distillationthe solvent is distilled off under reduced pressure
6. customThe residue is purified by means of a silica gel column chromatography (hexane:ethyl acetate:acetone=1:1:1)