Purines. LXXII. Oxidation of N6-Alkyladenines with m-Chloroperoxybenzoic Acid Leading to N6-Alkyladenine 1-Oxides.
作者:Taisuke ITAYA、Kazuo OGAWA、Yasutaka TAKADA、Tozo FUJII
DOI:10.1248/cpb.44.967
日期:——
Oxidations of N6-methyladenine (8a) and N6-benzyladenine (8b) with m-chloroperoxybenzoic acid (MCPBA) in methanol have been found to afford the N(1)-oxides 7a, b in 36% and 35% yields, respectively. The structure of 7b has been established by leading it to N6-methoxyadenine (10) through O-methylation, Dimroth rearrangement, and nonreductive debenzylation. On the other hand, N6, N6-dimethyladenine (16) afforded the N(3)-oxide 17 in 40% yield on treatment with MCPBA in methanol. On the basis of these findings, together with data accumulated for N-oxidations of adenine, Nx-monosubstituted adenines, and 6-substituted purines, the formation of hydrogen bonding between the 6-amino NH and the carbonyl oxygen of a peroxycarboxylic acid may account for regioselective N(1)- and N(7)-oxidations of adenine and Nx-monosubstituted adenines.
研究发现,N6-甲基腺嘌呤(8a)和 N6-苄基腺嘌呤(8b)在甲醇中与间氯过氧苯甲酸(MCPBA)发生氧化反应,可得到 N(1)-oxides 7a,b,收率分别为 36% 和 35%。通过 O-甲基化、Dimroth 重排和非还原性去苄基化,将 7b 引向 N6-甲氧基腺嘌呤(10),从而确定了 7b 的结构。另一方面,N6,N6-二甲基腺嘌呤(16)经甲醇中的 MCPBA 处理后可得到 N(3)-氧化物 17,收率为 40%。根据这些研究结果,以及在腺嘌呤、Nx-单取代腺嘌呤和 6-取代嘌呤的 N-氧化反应中积累的数据,6-氨基 NH 与过氧化羧酸的羰基氧之间形成氢键可能是腺嘌呤和 Nx-单取代腺嘌呤发生区域选择性 N(1)-氧化反应和 N(7)-氧化反应的原因。