反应详情

A mixture of methyl 4-benzyloxycarbonylpiperazine-2-carboxylate (1.2 g) obtained in Reference Example 21, triethylamine (0.9 g) and dichloromethane (15 ml) is added dropwise, taking 5 minutes while stirring at 0° C., to a solution of 3,4,5-trimethoxybenzoyl chloride (1.08 g) in dichloromethane (10 ml). The reaction mixture is stirred at room temperature for 10 minutes, and then poured into 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=2:2:1) to give methyl 4-benzyloxycarbonyl-1-(3,4,5-trimethoxybenzoyl)-piperazine-2-carboxylate as a colorless oily product (2.1 g).

1. additionis added dropwise
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=2:2:1)