On treatment with an excess of imidazole in boiling N, N-dimethylformamide (DMF) for 30 min, 9-ethyl-1-(2-hydroxyethyl)adenine hydrobromide (4a) afforded the corresponding 1-[2-(1H-imidazol-1-yl)ethyl]hypoxanthine derivative (13a) in 52% yield. The 1-(3-hydroxypropyl) homologue (4b) and 1-(2-hydroxyethyl)adenosine perchlorate (4c) reacted similarly with imidazole, giving the corresponding deaminated products (13b and 13c). Treatment of 4a with pyridine or thiophenol in boiling DMF also caused a similar deamination, furnishing the corresponding hypoxanthine derivative (16 or 17) with replacement of the hydroxy group by the nucleophile. The reaction of 4a with sodium ethoxide in boiling EtOH failed to cause deamination but gave the rearranged product (6a) in 95% yield. The free base (15) of 4a did not give the deaminated product (13a) when treated with imidazole in boiling DMF, and 4a alone was stable in boiling DMF for at least 30 min. On the basis of these results, a probable mechanism is proposed for the deamination.
在沸腾的 N,N-二
甲基甲
酰胺(
DMF)中用过量的
咪唑处理 30 分钟后,9-乙基-1-(2-羟乙基)
腺嘌呤氢溴酸盐(4a)得到了相应的 1-[2-(
1H-咪唑-1-基)乙基]
次黄嘌呤衍
生物(13a),产率为 52%。1-(3-羟基丙基)同系物(4b)和 1-(2-羟乙基)
腺苷高氯酸盐(4c)与
咪唑发生类似反应,得到相应的
脱氨基产物(13b 和 13c)。在沸腾的
DMF 中用
吡啶或
噻吩酚处理 4a 也会引起类似的
脱氨基反应,生成相应的
次黄嘌呤衍
生物(16 或 17),羟基被亲核体取代。4a 与
乙醇钠在沸腾的 EtOH 中的反应未能引起
脱氨基反应,但得到了重排产物(6a),收率为 95%。4a 的游离碱 (15) 在沸腾的
DMF 中与
咪唑反应时不会生成
脱氨基产物 (13a),而 4a 本身在沸腾的
DMF 中至少稳定 30 分钟。根据这些结果,提出了
脱氨基的可能机理。