hydroxide. A similar C-glycosylation of ethyl thiophene-3-carboxylate with 1,2,3,5-tetra-O-acetyl-4-thio-D-ribofuranose catalyzed by stannic chloride afforded an anomeric mixture of 2- and 5-glycosylated regioisomers. Deacetylation of ethyl 5-(2,3,5-tri-O-acetyl)-beta-D-(4'-thioribofuranosyl)thiophene-3-carboxylate (13beta) with methanolic ammonia and treatment of the ethyl ester with ammonium hydroxide gave
呋喃硫呋喃[5β-D-(4'-
硫代
呋喃呋喃糖基)
呋喃-3-羧酰胺,1]和
噻吩硫呋喃[5β-D-(4'-
硫代
呋喃呋喃糖基)
噻吩-3-甲酰胺,2]的合成,两个C-
硫代
核糖核苷类似物描述了
噻唑呋林的衍
生物。直接
三氟乙酸催化
呋喃-3-
羧酸乙酯与1-O-乙酰基-2,3,5-三-O-苄基-4-
硫代-D-
呋喃呋喃糖的C-糖基化反应,得到2-和5-糖基化的区域异构体,作为α和β异头物的混合物。将5-(2,3,5-三-O-苄基)-β-D-(4'-
硫代
呋喃呋喃糖基)
呋喃-3-
甲酸乙酯(6beta)脱苄基,然后通过与
四氢呋喃反应而转化为相应的酰胺(
呋喃硫呋喃)氢氧化
铵。
噻吩-3-
羧酸乙酯与1,2,3的相似C-糖基化
氯化锡催化的5-四-O-乙酰基-4-
硫代-D-
呋喃呋喃糖得到2-和5-糖基化的区域异构体的异头混合物。用
甲醇氨将5-(2,3,5-三-O-乙酰基)-β-D-(4'-
硫代
呋喃呋喃糖基)
噻吩-3-
羧酸乙