Synthesis of novel photolabile glycosides from methyl 4,6-O-(o-nitro)benzylidene-α-d-glycopyranosides
作者:Chen-Jiang Zhu、Hua Yi、Guo-Rong Chen、Juan Xie
DOI:10.1016/j.tet.2008.09.018
日期:2008.11
6-O-(o-nitro)benzyl group have been prepared from the corresponding methyl 4,6-O-(o-nitro)benzylidene α-d-glycopyranosides. Regioselective cleavage with BF3·Et2O/Et3SiH led to the methyl 6-O-(o-nitro)benzyl gluco- and manno-α-d-glycopyranosides 3 and 6. Inversion of configuration at 4-OH position of gluco and manno derivatives offered the otherwise inaccessible methyl 6-O-(o-nitro)benzyl galacto- and talo-α-d-glycopyranosides
由相应的甲基4,6- O-(邻-硝基)亚苄基α-d-吡喃葡萄糖苷制备了带有4-或6- O-(邻-硝基)苄基的新型光不稳定糖衍生物。用BF 3 ·Et 2 O / Et 3 SiH的区域选择性切割产生甲基6- O-(邻硝基)苄基葡萄糖-和甘露糖-α-d-吡喃葡萄糖苷3和6。葡萄糖和甘露糖衍生物在4-OH位置的构型反转提供了否则无法获得的甲基6- O-(ö硝基)苄基半乳糖-和距骨-α-d-glycopyranosides 4,5,和7。与PhBCl 2 / Et 3 SiH(3当量试剂,在-78°C下10分钟)仔细反应,得到所需的甲基4- O-(邻硝基)苄基葡萄糖-和甘露糖-α-d-吡喃葡萄糖苷8和9的产量很高。然而,与6当量的PhBCl 2 / Et 3 SiH长时间反应转化了甲基4,6- O-(邻硝基)亚苄基α-d-吡喃葡萄糖苷11变成还原的d-葡萄糖醇衍生物15。5,6-二醇功能的氧化裂