硫酸水相单端基保护法合成 N-(2-羟丙基)哌嗪

文章以哌嗪(PZ)和环氧丙烷(PO)为原料, 硫酸 $ \left(\mathrm{H}_{2}\mathrm{SO}_{4}\right) $为单端基保护剂, 在水相中 PZ 首先与 $ H_{2}SO_{4} $ 发生单质子化反应生成 $ \mathrm{PZ}(\mathrm{H})^{+} $, 再与亲电试剂 PO 发生反应, 通过 $ \mathrm{Ba(OH)}_{2} $ 脱保护后, 过滤分离 $ BaSO_{4} $ 沉淀制得 N-(2-羟丙基)哌嗪(HPPZ)。该研究考察了 PZ 质子化程度、PZ 初始质量和 PO 用量对 HPPZ 收率的影响, 结果表明, 当 50.0 mL 水中 PZ 初始质量为 10.0 g, PZ, $ H_{2}SO_{4} $, PO 三者的摩尔比为 2:1:2 时, 初始 pH 值为 8.23, PZ 单边反应生成 HPPZ 的收率可达 84%, 显著优于 PZ 与 PO 直接水相法合成 HPPZ 的收率。

In this paper, piperazine(PZ) and propylene oxide(PO) were adopted as reactants, and sulfuric acid $ \left(\mathrm{H}_{2}\mathrm{SO}_{4}\right) $ was applied to protect the mono-ended group. PZ was first reacted with $ H_{2}SO_{4} $ in aqueous phase to give $ \mathrm{PZ}(\mathrm{H})^{+} $, and further reacted with electrophilic reagent PO. The deprotection was carried out by adding $ \mathrm{Ba(OH)}_{2} $, and N-(2-hydroxypropyl) piperazine(HPPZ) was prepared after the separation of $ BaSO_{4} $. The influences of the protonation of PZ, the initial concentration of PZ, and the addition amount of PO on the HPPZ yield were also investigated. The results show that the HPPZ yield can reach 84% by unilateral reaction of PZ when the initial concentration of PZ is 10.0 g in 50.0 mL water, the molar ratio of PZ, $ H_{2}SO_{4} $, and PO is 2:1:2, and the initial pH value of the solution is 8.23, which is significantly superior than that by the direct aqueous phase reaction of PZ with PO.