合成路线1

4(R)-Aminocyclopentane-(1S,2R,3S)-triol 2,3-acetonide (I) is condensed with 4,6-dichloro-5-nitro-2-propylthiopyrimidine (II) in the presence of diisopropylethylamine in THF to afford the aminopyrimidine adduct (III), which is reduced to the diamine (IV) by means of iron powder in acetic acid. Cyclization of diamine (IV) employing isoamyl nitrite in hot acetonitrile followed by displacement of the resulting 6-chloro-8-azapurine (V) with ammonia in THF gives the azaadenine (VI). The lithium alkoxide of cyclopentanol (VI) is then alkylated with methoxycarbonylmethyl triflate (VII), producing ether (VIII). After conversion of amine (VIII) to the corresponding bromide (IX) by diazotization with isoamyl nitrite in bromoform, bromide displacement with 2-(3,4-difluorophenyl)cyclopropylamine (X) gives adduct (XI). Finally, DIBAL reduction of the ester function of (XI) provides acetonide (XII), which is finally hydrolyzed under acidic conditions to furnish the title compound (1, 2). Scheme 1.