Reactions of phenyl chlorosulfate at OH-2 and OH-3 of aldohexopyranose derivatives. Competing substitution and displacement reactions
作者:Magdy M. Abdel-Malik、Arthur S. Perlin
DOI:10.1016/0008-6215(89)84145-x
日期:1989.7
may be mono- or di-phenylsulfates (or both), 2,3-cyclic sulfates, or 2,3-oxiranes. For example, in the reaction of methyl 4,6- O -benzylidene-α- d -glucopyranoside with two equivalents of phenyl chlorosulfate at +25°, the products were the 2,3-disulfate (10%), 2,3-cyclic sulfate (77%), and 2,3- allo epoxide (4%), whereas, at −25°, by far the major product was the 2-phenylsulfate (79%). Intramolecular
摘要氯代硫酸钠-氢化钠与甲基4,6-O-亚苄基亚乙基己基吡喃吡喃糖苷的反应具有多种亲核取代和取代过程,涉及糖苷的OH-2和-3。取决于这些因素,例如这两个羟基的相对取代率及其构型以及温度和化学计量,产物可能是单苯硫酸盐或二苯硫酸盐(或两者),2,3-环硫酸盐或2 ,3-环氧乙烷。例如,在4,6-O-亚苄基-α-d-吡喃葡萄糖苷与两当量的氯代硫酸苯酯在+ 25°的反应中,产物为2,3-二硫酸盐(10%),2,3-环硫酸盐(77%)和2,3-异环氧化物(4%),而在-25°时,到目前为止,主要产物是2-苯基硫酸盐(79%)。在甲基4,6-O-亚苄基-α-d-α-吡喃果糖苷的反应中很容易促进分子内位移,以致获得的唯一产物是2,3-脱水-甘露糖苷-(主要)和-异位吡喃糖苷。基于它们的核磁共振特征,考虑了2,3-环硫酸盐的构象。