Selective deacetylation reactions of the peracetylated reducing disaccharides (1), (5), (9), (15), β-D- glucopyranose (17) and 2-acetamido-2-deoxy-β-D-glucopyranose (19), with 1.2 equiv. Of hydrazine hydrate in acetonitrile, gave predominantly the corresponding heptaacetates (2), (6), (10), (16), the tetraacetate (18) and the triacetate (20), with the free hydroxy group at C1. Reaction of (1) with 1.2 equiv. of hydrazine hydrate in N,N- dimethylformamide also afforded the heptaacetate (2), but in lower yield. When reactions of (1), (5) and (9) were performed with 2.5 equiv. of hydrazine hydrate, deacetylation also occurred at other positions to afford the corresponding hexaacetates (3), (7), (11) and (12), with hydroxy groups at C 1,2 or C 1,3, and the pentaacetates (4), (8) and (13), with hydroxy groups at C 1,2,3. Maltose octaacetate (9), in addition, yielded the tetraacetate (14) in which the free hydroxy groups were located at C1,2,2',3. Compound (15) on treatment with 2.5 equiv. of hydrazine hydrate afforded an intractable mixture. The reaction of methyl 2,3,4,6-tetra-O-acetyl-α-D-glucopyranoside (21) with 2.5 equiv. of hydrazine hydrate gave the 3,4,6-triacetate (22), a mixture of the 2,6- and the 3,6-diacetates (23) and (24), respectively, the 4,6-diacetate (25), and the 6-acetate (26).
过乙酰化还原二糖 (1)、(5)、(9)、(15)、β-
D-吡喃葡萄糖 (17) 和 2-乙酰
氨基-2-脱氧-β-
D-吡喃葡萄糖 (19) 与 1.2 等当量的
肼水合物在
乙腈中进行选择性脱乙酰化反应,主要得到相应的七
乙酸酯 (2)、(6)、(10)、(16)、
四乙酸酯 (18)
乙腈中的
水合
肼反应,主要得到相应的七
乙酸酯(2)、(6)、(10)、(16)、
四乙酸酯(18)和
三乙酸酯(20),其游离羟基位于 C1。将(1)与 1.2 等量的
水合
肼在
N,N-二甲基甲酰胺中反应,也能得到庚
乙酸酯(2),但产量较低。当用 2.5 等量的
水合
肼对(1)、(5)和(9)进行反应时,在其他位置也会发生脱乙酰化反应,从而得到相应的六
乙酸酯(3)、(7)、(11)和(12)(羟基位于 C 1,2 或 C 1,3)以及五
乙酸酯(4)、(8)和(13)(羟基位于 C 1,2,3)。此外,
麦芽糖八
乙酸酯(9)可生成
四乙酸酯(14),其中的游离羟基位于 C1,2,2',3。化合物 (15) 在与 2.5 等量的
水合
肼处理后,生成了一种难溶于
水的混合物。2,3,4,6-O-四乙酰基-α-
D-吡喃葡萄糖苷甲酯 (21) 与 2.5 等量的
水合
肼反应,得到 3,4,6-
三乙酸酯 (22)、分别为 2,6- 和 3,6- 二
乙酸酯 (23) 和 (24) 的混合物、4,6-二
乙酸酯 (25) 和 6-
乙酸酯 (26)。