Synthesis, glycosylation and photolysis of photolabile 2-(2-nitrophenyl)propyloxycarbonyl (NPPOC) protected glycopyranosides
摘要:
光敏性NPPOC基团成功引入到各种糖吡喃苷的6位,以91–97%的产率合成。用适当的受体对NPPOC保护的苯基β-D-硫葡萄糖苷和半乳糖苷进行糖苷化反应,可以良好产出相应的二糖。在−40 °C的CH3CN中进行糖苷化反应时,获得了优良的β立体选择性(β/α≥ 10/1)。此外,6-O-NPPOC硫葡萄糖苷6也可以方便地转化为相应的葡萄糖吡喃糖或葡萄糖基氟化物。对6-O-NPPOC二乙酮D-半乳糖4的光解研究显示,在CH3CN中存在水或DBU的条件下,在365 nm照射下进行。以100 µM的浓度,在5分钟的照射后实现了对4的光裂解,半衰期分别为37秒(10%水)、75秒(1当量DBU)或87秒(0.05 M DBU)。在0.05 M DBU存在的情况下,可以避免亚硝基副产物的形成。所有NPPOC保护的单糖或二糖都可以通过在CH3CN中以365 nm的波长光解,并在水或DBU存在下去除,产率超过87%。
Synthesis, glycosylation and photolysis of photolabile 2-(2-nitrophenyl)propyloxycarbonyl (NPPOC) protected glycopyranosides
作者:Hua Yi、Stéphane Maisonneuve、Juan Xie
DOI:10.1039/b908404e
日期:——
The photolabile NPPOC group has been successfully introduced into the 6-position of various glycopyranosides in 91–97% yield. Glycosylation of NPPOC-protected phenyl β-D-thiogluco- and galactopyranosides with appropriate acceptors afforded the corresponding disaccharides in good yield. Excellent β-stereoselectivity (β/α≥ 10/1) can be obtained when the glycosylation was realized in CH3CN at −40 °C. Furthermore, the 6-O-NPPOC thioglucoside 6 can also be readily converted into the corresponding glucopyranose or glucosyl fluoride. The photolysis of 6-O-NPPOC diacetone D-galactose 4 has been studied by UV–vis absorption in CH3CN in the presence of water or DBU at 365 nm. At 100 µM concentration, photocleavage of 4 was accomplished after 5 min irradiation, with t1/2 = 37 s (10% water), 75 s (1 equiv. DBU) or 87 s (0.05 M DBU). The formation of the nitroso byproduct can be avoided in the presence of 0.05 M DBU. All the NPPOC-protected mono- or disaccharides can be readily removed by photolysis at 365 nm in CH3CN the presence of water or DBU in more than 87% yield.
光敏性NPPOC基团成功引入到各种糖吡喃苷的6位,以91–97%的产率合成。用适当的受体对NPPOC保护的苯基β-D-硫葡萄糖苷和半乳糖苷进行糖苷化反应,可以良好产出相应的二糖。在−40 °C的CH3CN中进行糖苷化反应时,获得了优良的β立体选择性(β/α≥ 10/1)。此外,6-O-NPPOC硫葡萄糖苷6也可以方便地转化为相应的葡萄糖吡喃糖或葡萄糖基氟化物。对6-O-NPPOC二乙酮D-半乳糖4的光解研究显示,在CH3CN中存在水或DBU的条件下,在365 nm照射下进行。以100 µM的浓度,在5分钟的照射后实现了对4的光裂解,半衰期分别为37秒(10%水)、75秒(1当量DBU)或87秒(0.05 M DBU)。在0.05 M DBU存在的情况下,可以避免亚硝基副产物的形成。所有NPPOC保护的单糖或二糖都可以通过在CH3CN中以365 nm的波长光解,并在水或DBU存在下去除,产率超过87%。