Synthesis, regioselective hydrogenolysis, partial hydrogenation, and conformational study of dioxane and dioxolane-type (9′-anthracenyl)methylene acetals of sugars
作者:Zsolt Jakab、Attila Mándi、Anikó Borbás、Attila Bényei、István Komáromi、László Lázár、Sándor Antus、András Lipták
DOI:10.1016/j.carres.2009.09.007
日期:2009.12
ring-opening reaction of the endo isomer of the methyl 2,3-O-(9'-anthracenyl)methylene-alpha-L-rhamnopyranoside took place with complete selectivity resulting in the axial (9'-anthracenyl)methyl ether, whereas a 1:1 mixture of the axial and equatorial ethers was formed upon the same reaction of the exo isomer. Catalytic hydrogenation of the sugar acetals resulted in (9',10'-dihydro-9'-anthracenyl)methylene
甲基2,3-二-O-甲基-α-D-吡喃葡萄糖苷的二恶烷型(9'-蒽基)亚甲基缩醛用LiAlH(4)/ AlCl(3)(3:1)或Na(CN)裂解BH(3)-HCl区域选择性地分别提供4-或6-O-(9'-蒽基)甲基醚。二氧戊环型乙缩醛的外向异构体和内向异构体的氢解反应被证明是由乙缩醛碳的构型以及相邻的游离羟基的分子内参与引起的。2,3-O-(9'-蒽基)甲基-甲基-α-L-鼠李糖吡喃糖苷的内异构体的开环反应完全选择性地产生了轴向(9'-蒽基)甲基醚,而在外型异构体的相同反应下,形成了轴向和赤道醚的1:1混合物。糖缩醛的催化加氢导致(9' ,10′-二氢-9′-蒽基)亚甲基衍生物而不会影响缩醛中心。进行了高温分子动力学模拟和DFT(密度泛函理论)几何优化,以研究二恶烷型(9',10'-dihydro-9'-蒽基)亚甲基缩醛的构象。