( 8 and 9 ). Hydrolysis of the latter compounds, followed by acetylation, yielded anomeric mixtures of branched-chain sugar triacetates 10 and 11 . These were condensed with bis(trimethylsilyl)uracil and the products deacylated with methanolic ammonia to afford in high yield the title nucleosides 13 and 15 .
摘要描述了3'- C-乙基(和3'-C-丁基)
尿苷(13和15)的合成。将乙基(和丁基)
溴化镁或相应的烷基
锂加到1,2:5,6-二-O-异亚丙基-α-d-
核糖-
呋喃诺斯-3-ulose(1)中,得到3-C-乙基(和3-C-丁基)-1,2:5,6-二-O-异亚丙基-α-d-
呋喃呋喃糖(2和3)。2和3的选择性
水解,然后5,6
-二醇的
高碘酸裂解并随后还原,得到二醇6和7。后一种化合物的选择性
苯甲酰化得到5-O-
苯甲酰基-3-C-乙基(和3-C-丁基)-1,2-O-异亚丙基-α-d-
呋喃核糖(8和9)。后一种化合物的
水解,然后进行乙酰化,得到支链糖
三乙酸酯10和11的异头混合物。