1992 Volume 40 Issue 12 Pages 3201-3205
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.
