1,2和1,3-缩水内醚糖衍生物的制备, 构象及其糖苷化反应

吡喃糖的1,2-及1,3-缩水内醚苄醚由相应的吡喃糖的C-2氧负离子(对1,3-缩水内醚是C-3氧负离子)与连有氯原子的C-1经分子内关环反应而制备, 而有些吡喃糖的1,2-缩水内醚苄醚是由相应的吡喃糖的C-1氧负离子与连有对甲苯磺酰氧基的C-2经分子内关环(倒关环)反应而得。呋喃糖的1,2-缩水内醚苄醚只能用倒关环法合成。1,2-(或1,3-)缩水内醚糖的开环反应通常给出1,2-反式连接(对1,3缩水内醚是1,3反式连接)的糖苷键。1,2-及1,3-缩水内醚糖的构象分析是通过^1H NMR测定及分子力学计算的方法而完成的。

Synthesis, conformation, and glycosidic coupling reaction of 1,2- and 1,3-anhydro sugar derivatives

The synthesis of 1,2- and 1,3-anhydro glycopyranose benzyl ethers ws successfully achieved via intramolecular SN2 reaction of the corresponding C-2 (or C-3 for 1,3-anhydro sugars) alkoxide with C-1 bearing chloride, and the synthesis of some 1,2-anhydro pyranoses by the intramolecular reaction of the corresponding C-1 alkoxide with C-2 bearing tosyloxy group (inverse ring closure). The synthesis of 1,2-anhydro glycofuranose benzyl ethers was carried out only by the inverse ring closure. Ring opening of the 1,2- and 1,3-anhydro sugars usually afforded 1,2-trans and 1,3-trans linked glycosides respectively. Conformational analysis of the 1,2- and 1,3-anhydro sugars was performed by ^1H NMR spectrometry and molecular mechanics calculations.