The first total synthesis of the 8-oxopurine 8, a constituent of the marine sponge Hymeniacidon sanguinea GRANT, has been achieved via two alternative routes starting from 8-bromo-9-methyladenine (11), which is obtainable from 9-methyladenine (10) by bromination. The first route includes methylation of 11 with MeI to give the 1-methylated product 13·HI, conversion of 13·HI into the free base 13, and treatment of 13 with NaOAc in boiling AcOH to produce 8 in 25% overall yield (from 10). The second route includes treatment of 11 with boiling 1 N aqueous NaOH and methylation of the resulting 8-oxo derivative 12 with MeI, affording 8 in 63% overall yield (from 10). The rearranged isomer 15 and the N6 -acetyl derivative 9 have also been synthesized.
8- 氧代
嘌呤 8 是海洋海绵 Hymeniacidon sanguinea GRANT 的一种成分,它的首次全合成是通过两条不同的路线实现的,第一条路线是从 8-
溴-
9-甲基腺嘌呤(11)开始,后者可通过
溴化从
9-甲基腺嘌呤(10)中获得。第一种方法包括用 MeI 对 11 进行甲基化,得到 1-甲基化产物 13-HI,将 13-HI 转化为游离碱 13,然后用 NaOAc 在沸腾的 AcOH 中处理 13,得到 8,总产率为 25%(从 10)。第二种方法包括用沸腾的 1 N NaOH
水溶液处理 11,然后用 MeI 将得到的 8-氧代衍
生物 12 甲基化,得到 8,总产率为 63%(以 10 为原料)。此外,还合成了重排异构体 15 和 N6-乙酰基衍
生物 9。