Efficient and convenient procedures are reported for the synthesis of the title compound 9 and its α-anomer 10. Thus, the direct condensation of phthalimide with unprotected 2-deoxy-D-ribose (1) using the P4O10/H2O/n-Bu3N reagent in CHCl3 at 40°C followed by acetylation afforded the di-O-acetyl-phthalimido derivatives 2 and 3 which can also be synthesized via reaction of DBU phthalimide salt with 4-acetoxy-5-hydroxy-2-pentenal 5. Reaction of 2 with silylated thymine using the Lewis acid trimethylsilyl triflate as catalyst afforded compounds 7 and 8 which were separated by fractional crystallization, and deprotected by treatment with 33 % methylamine/ethanol to give the corresponding 3-aminonucleosides 9 and 10, respectively.
据报道,标题化合物9及其α-异构体10的合成过程高效且便捷。因此,在40°C下,在
CHCl3中使用P4O10/
H2O/n-Bu3N试剂,将邻苯二甲
酰亚胺与未保护的
2-脱氧-D-核糖(1)直接缩合,然后进行乙酰化,得到二-O-乙酰基-邻苯二甲
酰亚胺衍
生物2和3,这些衍
生物也可以通过
DBU邻苯二甲
酰亚胺盐与4-乙酰氧基-5-羟基-
2-戊烯醛5的反应来合成。2与
硅化胸腺
嘧啶的反应,使用
路易斯酸三甲基
硅基
三氟甲磺酸盐作为催化剂,得到化合物7和8,通过分馏结晶分离,并用33%的
甲胺/
乙醇处理脱保护,分别得到相应的3-
氨基核苷9和10。