一种酚羟基苄基保护基的脱除方法

Removal of Benzyl Protective Groups of Phenolic Hydroxyl Groups

提出了一种脱除酚类化合物羟基苄基保护基的方法。采用多聚磷酸(PPA)-浓盐酸-乙醇体系脱除苄基保护基,通过单因素实验考察PPA物质的量、浓盐酸与PPA体积比、反应时间以及反应温度对产率的影响。结果表明,n(PPA)=0.2 mmol、V(浓盐酸)∶V(PPA)=100∶1、反应时间3 h、反应温度85℃为最佳反应条件。采用优化条件得到9个脱苄基化合物,产率为70.4%~92.7%,其中2'-苄氧基取代查尔酮脱掉苄基的同时环合得到二氢黄酮。所得产物结构经MS、1HNMR及13CNMR进行确证。

A method for removal of benzyl-type protective groups of phenolichydroxyl groups in phenolic compounds was reported.Removing benzyl-type protective groups was carried out with polyphosphoric acid（PPA）-concentrated hydrochloric acid-ethanol system.Effects of PPA equivalent,volume ratio of concentrated hydrochloric acid to PPA,reaction time and reaction temperature on the yield were investigated via single factor tests.Results indicated that PPA equivalent,volume ratio,suitable reaction time and reaction temperature was 0. 2 mmol,100 ∶1,3 h and 85 ℃ respectively.Nine products were prepared at the optimum conditions in good yields of 70. 4% ~ 92. 7%.Specifically,corresponding flavanones were formed in the deprotection procedure of benzyl group of 2＇-benzyloxy substituted chalconesusing this reaction system. Structures of all compounds were confirmed by MS,^1HNMR and ^13CNMR.