溴代乙酰葡萄糖和溴代乙酰鼠李糖的便捷合成

Facile preparation of acetobromoglucose and acetobromorhamnose

摘要:

以高氯酸为催化剂，D-葡萄糖和L-鼠李糖分别与乙酸酐反应，制得相应的全乙酰化糖，不经分离直接加入乙酰溴和甲醇，利用反应生成的溴化氢原位发生溴代反应，一锅法制备了溴代乙酰葡萄糖和溴代乙酰鼠李糖，收率分别达到92.5%和85.6%。从产品结晶后的母液中，以干燥的二氯甲烷作溶剂，采用重结晶法分离得到溴代乙酰鼠李糖合成的副产物2,3,4-三-O-乙酰基鼠李糖。 产品和副产物的结构均经过核磁共振氢谱、碳谱和高分辨质谱确认。该法的显著优点是：试剂廉价易得、操作简单方便、产品收率高，可用于工业生产。

Abstract:

A facile and efficient one-pot two-step protocol for the preparation of acetobromoglucose and acetobromorhamnose was developed. D-glucose and L-rhamnose were separately treated with HClO4/ Ac2O, followed by addition of AcBr/ MeOH without isolation of the corresponding peracetylated sugars intermediates, which were mono-brominated by HBr generated in situ from AcBr and MeOH. Acetobromoglucose and acetobromorhamnose were obtained in yields of 92.5% and 85.6%, respectively. 2,3,4-Tri-O-acetyl-rhamnopyranose as a by-product during the synthesis of acetobromorhamnose, was recrystallized with dry dichloromethane from the mother liquor of acetobromorhamnose. The above mentioned products and by-product were characterized with 1HNMR, 13CNMR and HRESIMS. This method has distinctive advantages including easy available reagents, convenient experimental procedures and high yields. More importantly, this method could be adapted for industrial production of the titled compounds as well.