The isomerization with boron trifluoride–ether of 4-N-acetyl-1-(2,3-O-isopropylidene-5,6-anhydro-β-D-allo- and -α-L-talo-furanosyl)cytosine (4) and (5), an epoxide mixture obtained in two steps from protected cytidine, gave 4-acetamido-1-(2,5′:2,6′-dianhydro-2′,3′-O-isopropylidene-α-L-talofuranosyl)-1,2-dihydropyrimi-dine (7), the constitution of which was confirmed by X-ray crystallography.
4- N-乙酰基-1-(2,3 - O-异亚丙基-5,6-脱
水-β - D - allo-和-α- L -talo-
呋喃糖基)
胞嘧啶的
三氟化硼-醚异构化反应(4)和(5),由保护的
胞苷分两步得到的
环氧化物混合物,得到4-乙酰
氨基-1-(2,5':2,6'-dianhydro-2',3' - O-异亚丙基-α- L -talofuranosyl)-1,2-dihydropyrimi-dine(7),其结构通过X射线晶体学证实。