反应详情

In 4.5N HCl-ethyl acetate solution (20 ml) is dissolved methyl 4-tert-butoxycarbonyl-1-(3,4,5-trimethoxybenzyl)piperazine-2-carboxylate (5.0 g) obtained in Reference Example 19, and the solution is left standing at room temperature for 5 hours. The reaction mixture is concentrated under reduced pressure to give crystalline methyl 1-(3,4,5-trimethoxybenzyl)-piperazine-2-carboxylate dihydrochloride (4.3 g). This product is recrystallized from ethanol to afford colorless needles, m.p. 170-175° C.

1. customobtained in Reference Example 19
2. waitthe solution is left
3. concentrationThe reaction mixture is concentrated under reduced pressure