was readily hydrolyzed in slightly acid conditions to give in almost quantitative yield 1-(3,5,6-tri- O -benzoyl-β- d -glucofuranosyl)uracil. This new synthetic method for nucleosides unprotected at O-2′ was also tested in other sugar series. In some cases, only the 1′,2′- trans -nucleosides were obtained, but in others, small yields (3–10%) of 1′,2′- cis -nucleosides were detected. The α-to-β ratio
摘要在没有任何催化剂的熔融过程中,用过量的双(三甲基
硅)尿
嘧啶处理3,5,6-三-O-苯甲酰基-α-d-
葡萄糖呋喃糖1,2-
亚硫酸盐,得到了1-(-)极好的收率。 3,5,6-三-O-苯甲酰基-2-O-三甲基甲
硅烷基-β-d-
葡萄糖基
呋喃糖基)尿
嘧啶,在弱酸性条件下容易
水解,几乎可以定量得到1-(3,5,6-tri -O-苯甲酰基-β-d-
葡糖呋喃糖基)尿
嘧啶。在其他糖系列中也测试了这种在O-2'处未保护的核苷的新合成方法。在某些情况下,仅获得了1',2'-顺式核苷,而在其他情况下,仅检测到了1',2'-顺式核苷的少量收率(3-10%)。α与β之比似乎取决于反应温度。2,4-二
甲氧基嘧啶还与糖1,2-
亚硫酸盐和4-O-甲基-1-(3,5,