Thiazole C-nucleosides IV. An entry to pent-1′-enopyranosylthiazole derivatives
作者:Lajos Kovács、Pál Herczegh、Gyula Batta、István Farkas
DOI:10.1016/s0040-4020(01)80986-8
日期:1991.7
a carbocation (I) and the stereochemistry of the incoming nucleophile was determined by the neighbouring 4′-acetoxy group. However, with trimethylsilyl cyanide a 2′,3′-unsaturated 1′-C-cyano derivative (26) was formed. The configuration and conformation of prepared unsaturated compounds was thoroughly studied and the presence of a conformational equilibrium 4H5 ⇌ 5H4 was deduced.
从2-(3',4'-二-O-乙酰基-2'-脱氧-L-赤-或-D-苏-戊-1'-烯吡喃基)乙基噻唑-4-羧酸乙酯(1,2)不同地官能化戊基-1'- enopyranosylthiazoles的合成(4-11,15-20)中的溶液在路易斯酸存在下,用不同的O,C,S-,N-和H-亲核试剂进行。区域和立体选择性反应是随着路易斯酸介导的碳正离子(I)的形成而进行的,传入亲核试剂的立体化学由相邻的4'-乙酰氧基确定。但是,对于三甲基甲硅烷基氰化物来说,是一种2',3'-不饱和1'-C-氰基衍生物(26)成立。的配置和准备的不饱和化合物的构象深入研究和构象平衡的存在4 ħ 5 ⇌ 5 ħ 4推导出。