Synthesis and hydrogenolysis of the methylene, ethylidene, isopropylidene, and diastereoisomeric 1-phenylethylidene acetals of β-l-arabino- and α-l-rhamnopyranoside derivatives
作者:András Lipták、Zoltán Szurmai、V.Anna Oláh、János Harangi、Lajos Szabó、Pál Nánási
DOI:10.1016/0008-6215(85)85218-6
日期:1985.4
diastereoisomers of 1-phenylethylidene acetals (acetophenone acetals) of methyl and benzyl β- l -arabinopyranoside and α- l -rhamnopyranoside were prepared. Acetal-exchange reactions gave only the endo -phenyl isomers; their 2- O - and 4- O -acetyl derivatives were isomerised into the exo -phenyl compounds. 1 H-N.m.r. data were used to determine the absolute configuration at the acetal carbon atom in these compounds
摘要分别制备了
甲基和
苄基β-1-L-阿拉伯
吡喃糖苷和α-1-R-
鼠李糖吡喃糖苷的1-
苯基亚乙基
缩醛(
苯乙酮缩醛)的非对映异构体。
缩醛交换反应仅产生内-
苯基异构体。它们的2-O-和4-O-
乙酰基衍
生物被异构化为外
苯基化合物。1 HN.mr数据用于确定这些化合物中
乙缩醛碳原子的绝对构型。与内
苯基异构体相比,外
苯基异构体的
甲基质子在较低的场共振。各种亚
甲基,亚乙基和异亚丙基衍
生物的
氢解反
应得到轴向醚。
苯乙酮衍
生物的内-
苯基异构体还产生了两种非对映异构形式的轴向1-
苯基
乙基醚。