Purines. LXXIII. Syntheses of 8-Alkoxy- and 8-Hydroxy-3-alkyladenines from 3-Alkyladenine 7-Oxides through 7-Alkoxy-3-alkyladenines.
作者:Taisuke ITAYA、Yasutaka TAKEDA、Tozo FUJII
DOI:10.1248/cpb.44.2025
日期:——
7-Alkoxy-3-alkyladenine perchlorates (9) were prepared from 3-alkyladenines (4) by N-oxidation followed by alkylation with alkyl halides in N, N-dimethylacetamide. The 7-methoxy derivatives 9d, g, j thus obtained afforded 3-methyl-8-hydroxyadenine (7a), 3-ethyl-8-hydroxyadenine (7b), and 3-benzyl-8-hydroxyadenine (7c) in 74%, 72%, and 39% yields, respectively, on treatment with boiling 0.1 N aqueous sodium hydroxide, whereas treatment of 9d, g, j with sodium methoxide in methanol at room temperature afforded 3-alkyl-8-methoxyadenines (10m, p, q) in 91%-98% yields. Similar treatment of 9d with sodium ethoxide in ethanol afforded 8-ethoxy-3-methyladenine (10n) in 89% yield. Compounds 10m, q were alternatively prepared from 9d, j in 77% and 84% yields, respectively, by treatment with 0.1 N aqueous sodium hydroxide in the presence of methanol. This method was suitable for the synthesis of the 8-benzyloxy compound 10o : it was obtained in 60% yield by treating 7-benzyloxy-3-methyladenine perchlorate (9f) with a mixture of aqueous sodium hydroxide and benzyl alcohol. Compounds 7 were alternatively prepared from 9 through 10. For example, 7c was obtained in 84% overall yield by treatment of 9j with sodium methoxide, followed by hydrolysis of the resulting 10q with boiling 1 N hydrochloric acid.On the other hand, methylation of 3-methyladenine 7-oxide (8a) with dimethyl sulfate in 0.1 N aqueous sodium hydroxide in the absence or presence of added methanol afforded N6, 3-dimethyladenine 7-oxide (14) in 13% or 14% yield, together with 7a (4% yield) or 10m (11%).
7- 烷氧基-3-烷基腺嘌呤高氯酸盐(9)由 3-烷基腺嘌呤(4)通过 N-氧化,然后在 N,N-二甲基乙酰胺中用烷基卤化物进行烷基化制备而成。由此得到的 7-甲氧基衍生物 9d、g、j 在沸腾的 0.1 N 氢氧化钠水溶液中分别以 74%、72% 和 39% 的产率得到 3-甲基-8-羟基腺嘌呤(7a)、3-乙基-8-羟基腺嘌呤(7b)和 3-苄基-8-羟基腺嘌呤(7c)。室温下,用甲醇中的甲醇钠处理 9d、g、j,可得到 3-烷基-8-甲氧基腺嘌呤(10m、p、q),收率为 91%-98%。用乙醇中的乙醇钠对 9d 进行类似处理,可得到 8-乙氧基-3-甲基腺嘌呤(10n),收率为 89%。在甲醇存在下,用 0.1 N 氢氧化钠水溶液处理 9d、j,分别以 77% 和 84% 的收率制备出化合物 10m、q。这种方法适用于合成 8-苄氧基化合物 10o:用氢氧化钠水溶液和苄醇的混合物处理 7-苄氧基-3-甲基腺嘌呤高氯酸盐(9f),产率为 60%。化合物 7 可由 9 至 10 交替制备。例如,用甲醇钠处理 9j,然后用沸腾的 1 N 盐酸水解得到 10q,总产率为 84%。另一方面,3-甲基腺嘌呤 7-氧化物(8a)与硫酸二甲酯在 0.1 N 氢氧化钠水溶液中发生甲基化反应,在没有或有添加甲醇的情况下,得到 N6,3-二甲基腺嘌呤 7-氧化物(14),收率为 13% 或 14%,同时得到 7a(收率为 4%)或 10m(收率为 11%)。