Methods were developed to prepare 1 -methyl-, 3-methyl- and 4-0-methyl-ψ-isocytidine by selective methylation.35O-Tetraisopropyldisiloxanyl-ψ isocytidine (8) was trimethylsilylated and then treated with MeI and, after deprotection, 1 -methyl-ψ isocytidine (6) was obtained. The 2deoxy analog (7) was also prepared in a similar manner from the 2deoxy analog (10) of 8. Treatment of 8 with CH2N2 afforded
方法的发展,以制备1-甲基,3-甲基和4-0甲基ψ-异
胞苷通过选择性methylation.3 5 O型四异丙-ψ异
胞苷(8)中的三甲基
硅烷化,然后用MeI处理,在脱保护后得到1-甲基-ψ异
胞苷(6)。2脱氧类似物(7被以相似的方式也制备)从2脱氧类似物(10)的8。用CH 2 N 2处理8得到主要产物3-甲基-ψ-异
胞苷衍
生物(19)。
重氮甲烷的甲基化也主要发生在2个脱氧类似物的N3上10至20。从19和20除去3 5 O-保护基团,分别得到3-甲基-ψ-异
胞苷(14)和其2-脱氧类似物(15)。另一方面,2-N-乙酰基-3 5 O-四异丙基二
硅氧烷基-tetra-异
胞苷(24)经CH 2 N 2处理,得到了4-O-甲基衍
生物(25)作为主要产物。随后25的脱保护得到4-O-甲基-ψ-异
胞苷(29)。aiv51b1p33b