In contrast to the N(3)-selectivity in N-alkylation, N-oxidation of 7-benzyladenine (17) with m-chloroperoxybenzoic acid in MeOH has been found to give 7-benzyladenine 1-oxide (18) in 76% yield. Alternatively, the same N-oxide (18) has been synthesized in 81% yield from 1-benzyl-4-(ethoxymethyleneamino)imidazole-5-carbonitrile(19) and hydroxylamine. Treatment of 1-benzyl-4-(hydroxyamino)imidazole-5-carbonitrile (24), obtained in 63% yield from the corresponding 4-nitro drivative (20) by catalytic hydrogenation (Pt/H2), with formamidine acetate in boiling EtOH furnished 7-benzyladenine 3-oxyde (23) in 78% yield. A UV spectroscopic approach indicated that the neutral species of 18 exists in H2O in the N(1)-oxide form rather than the N(1)-OH form (27).
与 N-烷基化中的 N(3)-选择性相反,在 MeOH 中用
间氯过氧苯甲酸对 7-苄基
腺嘌呤(17)进行 N-氧化,可得到 7-苄基
腺嘌呤 1-氧化物(18),收率为 76%。另一种方法是用 1-苄基-4-(乙氧基亚甲基
氨基)
咪唑-5-甲腈(19)和
羟胺合成相同的 N-氧化物(18),收率为 81%。在沸腾的 EtOH 中,用
乙酸甲脒处理 1-苄基-4-(羟基
氨基)
咪唑-5-甲腈(24)(从相应的 4-硝基二价化合物(20)通过催化加氢(Pt/H2)得到,收率为 63%),得到 7-苄基
腺嘌呤 3-氧化物(23),收率为 78%。紫外光谱法表明,18 的中性物种在
H2O 中以 N(1)-氧化物形式而不是 N(1)-OH 形式存在(27)。