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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 of removing hydroxybenzyl protecting group of phenolic compounds was proposed. The protective group of benzyl group was removed by using polyphosphoric acid (PPA) -saline hydrochloric acid-ethanol system. The effects of the amount of PPA, the volume ratio of concentrated hydrochloric acid to PPA, the reaction time and the reaction temperature on the yield were investigated by single factor experiments. The results showed that n (PPA) = 0.2 mmol, V (concentrated hydrochloric acid): V (PPA) = 100:1, reaction time 3 h and reaction temperature 85 ℃ were the best reaction conditions. Under optimized conditions, 9 debenzylated compounds were obtained with a yield of 70.4% -92.7%. The 2’-benzyloxy-substituted chalcone was cyclized simultaneously to give dihydroflavonoids. The structure of the obtained product was confirmed by MS, 1HNMR and 13CNMR.