Synthesis of Branched Dithiotrisaccharides via Ring-Opening Reaction of Sugar Thiiranes
作者:Evangelina Repetto、Verónica E. Manzano、María Laura Uhrig、Oscar Varela
DOI:10.1021/jo2018685
日期:2012.1.6
(3→3)-disulfide 19, which resulted from the oxidative dimerization of 17. However, the S-acetyl derivative of 17 could be obtained in good yield (62%) by LiAlH4 reduction of the crude mixture 17–19, followed by acetylation. The same sequence of reactions starting from 14 and the 1-thiolate of Galp afforded the per-O,S-acetyl derivative of Galp-β-S-(1→4)-3,4-dithio-α-d-Glcp-O-iPr (23), which was selectively
描述了从各自的六呋喃糖或六吡喃糖环氧前体合成5,6-和3,4-噻喃衍生物的令人满意的程序。通过1-thioaldoses硫杂丙环的受控开环反应物成功地完成,得到选择性,区域选择性和立体选择性,β-小号- (1→4)-3,4- dithiodisaccharides。例如,过-O-乙酰基-1-硫代葡萄糖(16)对2-丙基2,6-二-O-乙酰基-3,4-表硫基-α- d-吡喃半乳糖苷的C-4的区域选择性攻击(14)),得到衍生物GLC的p -β-小号- (1→4)-3,4- dithioGlc p - ø -我PR(17)。该硫二糖伴有在16和17之间形成的(1→3)-二硫化物18和对称的(3→3)-二硫化物19,这是由于17的氧化二聚作用而引起的。然而,小号-乙酰基衍生物的17可以以良好的收率(62%)的LiAlH通过获得4还原粗混合物的17 - 19,接着乙酰化。从开始反应的相同序列14和Gal的1