Stereoselective entry into the d-GalNAc series starting from the d-Gal one: a new access to N-acetyl-d-galactosamine and derivatives thereof
作者:Lorenzo Guazzelli、Giorgio Catelani、Felicia D’Andrea、Alessia Giannarelli
DOI:10.1016/j.carres.2008.11.018
日期:2009.2
A new stereoselective preparation of N-aceyl-D-galactosamine (1b) starting from the known p-methoxyphenyl 3,4-O-isopropylidene-6-O-(1-methoxy-1-methylethyl)-beta-D-galactopyranoside (10) is described using a simple strategy based on (a) epimerization at C-2 of 10 via oxidation-reduction to give the talo derivative 11, (b) amination with configurational inversion at C-2 of 11 via a S(N)2-type reaction
从已知的对甲氧基苯基3,4-O-异亚丙基-6-O-(1-甲氧基-1-甲基乙基)-β-D-吡喃半乳糖苷(使用基于(a)通过氧化还原在C-2处10的差向异构化得到滑石衍生物11(b)通过S(N)在C-2处11的构型反转的胺化的简单策略来描述10)在其2-亚酰胺基上进行2型反应,(c)对甲氧基苯基β-D-半乳糖胺糖苷14的端基异构脱保护,(d)完全脱保护。将相同的方法应用于通过以下方法直接获得的2,3:5,6:3',4'-三-O-异亚丙基-6'-O-(1-甲氧基-1-甲基乙基)-乳糖二甲基乙缩醛(4)乳糖的乙酰化,二糖β-D-GalNAcp-(1->