呋喃阿洛糖衍生物水解产物的结构确定

1,2;5,6-双-O-异丙叉基-3-C-硝甲基-α-D-呋喃阿洛糖（化合物1）在酸性条件下选择性脱除5,6-异丙叉基得到C-3位构型保持的水解产物1,2-O-异丙叉基-3-C-硝甲基-α-D-呋喃阿洛糖（化合物2）；化合物1先经过Moffatt脱水生成C-3硝基烯产物1,2;5,6-双-O-异丙叉基-3-脱氧-亚甲基硝基-α-D-呋喃木糖（化合物3），然后在酸性条件下选择性脱除5,6-异丙叉基过程中协同发生氧杂-Michael加成反应得到C-3位构型反转的水解产物1,2-O-异丙叉基-3-C-硝甲基-α-D-呋喃葡萄糖（化合物2′），两种产物化合物2和2′互为C-3差向异构体.通过¹H NMR、¹³C NMR、DEPT-135、¹H-¹H COSY、gHSQC和gHMBC等核磁共振（NMR）技术，对化合物2′的¹H和¹³C NMR数据进行了全归属．

Structural Elucidation of a Hydrolysis Product from Derivatives of Allofuranose

1,2-O-(1-methylethylidene)-3-C-methylnitro-α-D-allofuranose(2)was obtained through selective deprotection of1,2;5,6-Di-O-isproplidene-3-C-methylnitro-α-D-allofuranose(1)underanacidic condition. C-3 nitrostyrenes(3)was synthetizedthrough Moffatt dehydration from compound1underanacidic condition.A hydrolysis product 1,2-O-(1-methylethylidene)-3-C-methylnitro-α-D-glocufuranose(2')which hada reversedC-3 configuration wasobtained by an unexpected oxa Michael addition.Compounds2and2'were C-3 diasteroisomers.Compound2'was characterized withNMR spectroscopy techniques, including1HNMR,13CNMR,DEPT-135,1H-1H COSY, gHSQC and gHMBC.1H and 13Cchemical shiftsof compound2'were also fullyassigned. The molecular structure of compound2'was determined.