摘要
Aim To optimize the reaction condition for preparation of 3-spiro-1, 3, 4-oxadiazole substituted fructose and hydrolysis of its isopropylidenes stepwisely. Methods Cyclohexane was added to the reaction mixture every 8 h to remove acetic acid at 90 ℃. The isopropylidenes were hydrolyzed in 80% AcOH at 60 ℃ stepwisely in a reaction time- dependent manner. Results The yields of cyclization products 1b and 1c were improved from 53% and 51% to 74% and 79% respectively. The 1, 2-di-O-isopropylidene product 3 was obtained after 1 h and the total deprotected product 4 was obtained after 3 h in 80% AcOH at 60 ℃. Conclusion The yield of 1 is improved by cyclohexane-aided azeotropic removal of AcOH from the reaction mixture. Deprotection of 1 in 80% AcOH at 60 ℃ gives 3 or 4 after different time periods.
目的优化果糖(3-位)螺接1,3,4-口恶二唑化合物的合成条件,及选择性脱除两个异亚丙基的条件。方法向环合反应中每隔8小时添加环己烷,在90℃蒸馏带出反应生成的醋酸;将螺环化合物在60℃的80%AcOH溶液中反应,通过控制反应时间来选择性水解异亚丙基。结果通过与环己烷形成共沸物从溶液中除去醋酸,明显提高了反应1的收率;螺环化合物在60℃,80%AcOH溶液中在不同的时间分别生成了3和4两种脱保护产物。结论通过加入环己烷与醋酸共讲的方法来除去醋酸,提高了化合物1的收率。化合物1在80%的AcoH溶液中反应,经过不同的时间分别得到3和4两个脱保护产物。
基金
NationalNaturalSciencesFoundationofChina(30330690)
