Methyl 2-O-allyl-4,6-O-benzylidene-3-O-(2,3,4,6-tetra-O-acetyl-alpha-D-mannopyranosyl) -alpha-D-mannopyranoside (12) was prepared in 90% yield by Helferich glycosylation of methyl 2-O-allyl-4,6-O-benzylidene-alpha-D-mannopyranoside (9) with tetra-O-acetyl-alpha-D-mannopyranosyl bromide (11). Removal of the benzylidene group and second Helferich glycosylation with 11 led to methyl 2-O-allyl-3,6-di-O-(2
甲基2-O-烯丙基-4,6-O-亚苄基-3-O-(2,3,4,6-四-O-乙酰基-α-D-甘露
吡喃糖基)-α-D-甘露
吡喃糖苷(12)为通过用2-O-乙酰基-α-D-甘露
吡喃糖基
溴化物(11)对2-O-烯丙基-4,6-O-亚苄基-甲基-D-甘露
吡喃糖苷(9)进行Helferich糖基化以90%的产率制备。除去亚苄基和用11进行的第二次Helferich糖基化反应导致甲基2-O-烯丙基-3,6-二-O-(2,3,4,6-四-O-乙酰基-α-D-甘露
吡喃糖基)- α-
D-甘露糖吡喃糖苷(14),经过脱甲酰作用和Zemplén脱乙酰基作用后,得到标题化合物5。二糖甲基3-O-(α-D-甘露
吡喃糖基)-α-
甘露糖吡喃糖苷(7)和甲基6-O-( α-D-甘露
吡喃糖基)-α-D-甘露
吡喃糖苷(6)也已经合成。给出了化合物5、6和7的1H-nmr光谱的完整分配。