Regioselective intramolecular ring closure of 2-amino-6-bromo-2,6-dideoxyhexono-1,4-lactones to 5- or 6-membered iminuronic acid analogues: synthesis of 1-deoxymannojirimycin and 2,5-dideoxy-2,5-imino-d-glucitol
作者:Birgitte M. Malle、Inge Lundt、Tanja M. Wrodnigg
DOI:10.1039/b719631h
日期:——
aqueous base at pH 12, ring closure took place by 5-exo attack on the 5,6-epoxide leading to 2,5-dideoxy-2,5-imino-L-gulonic acid (9b), which was reduced to 2,5-dideoxy-2,5-imino-D-glucitol (9b). The method was further applied to 2-amino-6-bromo-2,6-dideoxy-D-galacto- as well as D-talo-1,4-lactones (14 and 15). However, only the corresponding six-membered ring 1,5-iminuronic acid mimetics, namely (2R
1-脱氧甘露糖霉素(8c)是由2-氨基-6-溴-2,6-二脱氧-D-甘露糖-1,4-内酯(7)通过分子内直接取代C-6溴的非水碱合成的处理,然后还原中间体甲酯。同样,使用pH值为12的碱水溶液,通过5-环氧对5,6-环氧的进攻,使环闭合,从而生成2,5-二脱氧-2,5-亚氨基-L-古洛糖酸(9b)至2,5-二脱氧-2,5-亚氨基-D-葡萄糖醇(9b)。该方法进一步应用于2-氨基-6-溴-2,6-二脱氧-D-半乳糖以及D-talo-1,4-内酯(14和15)。但是,只有相应的六元环1,5-亚氨基尿酸模拟物,即(2R,3R,4S,5R)-3,4,5-三羟基哌酸(2,6-dideoxy-2,6-imino-D -半乳糖酸16)和(2S,3R,4S,5R)-3,4,5-三羟基哌酸(2,6-dideoxy-2,6-imino-D-talonic acid,17),获得了。相应的对映异构体L-半乳酸酯以及L-talo-2-氨基-6-溴2