derivatives (6a or 6b) afforded, respectively, the ester 12 and amide 14. The dihydroxylation of the conjugated double bond in ester 12 or amide 14 was better achieved with osmium tetraoxide/barium chlorate, leading to the expected diols 13 and 15 as a mixture of two diastereoisomers. The desired compounds 1-4 were obtained after catalytic hydrogenation of compounds 12-15.
含有N-乙酰基
氨基葡萄糖氨基和
尿苷单元的C-
吡喃
葡萄糖基核苷(1-4)已被合成为
UDP-GlcNAc的不可
水解底物类似物,目的是抑制几丁质合酶。关键中间体4-(2'-(N-乙酰
氨基)-3',4',6'-三-O-苄基-2'-脱氧-α-
D-吡喃葡萄糖基)丁-2-烯酸(5 )是由全苄基化(N-乙酰
氨基)-α-C-烯丙基
葡糖苷(7)通过连续的氧化裂解,Wittig烯化和酯脱保护制备的。酸5与
尿苷衍
生物(6a或6b)的羟基或胺官能团偶合,分别得到酯12和酰胺14。用能更好地实现酯12或酰胺14中共轭双键的二羟基化。四氧化物/
氯酸
钡,得到两种非对映异构体混合物的预期二醇13和15。化合物12-15催化氢化后,得到所需的化合物1-4。