Purines. XI. The Synthesis of N-Alkoxyadenosines and Their 2', 3'-O-Isopropylidene Derivatives

摘要: Alkylation of adenosine 1-oxide (I) and its 2', 3'-O-isopropylidene derivative (V) with alkyl halides in N, N-dimethylacetamide furnished the corresponding 1-alkoxy derivatives (IIa-f). The free bases, obtained from IIa-f, readily underwent rearrangement to give isomeric N6-alkoxy (IVa-f) when heated water. Treatment 1-benzyloxyadenosine perchlorate (IIc : X=ClO4) water at pH 9.5 39-41°for 4 hr afforded ring-opened intermediate (IIIc)(79% yield), which was recyclized hot (pH 7) IVc. In alternative synthesis IVa, b, c, condensation 6-chloro-6-β-D-ribofuranosylpurine (VIa) appropriate alkoxyamines proceeded smoothly. Removal isopropylidene group IVe under acid conditions or exchange amination ethoxyamine 5 also yielded N-ethoxyadenosine (IVb).