合成路线1

The reaction of 2-azabicyclo[2,2,1]-5-hepten-3-one (I) with 2-nitrophenylsulfonyl chloride (II) by means of BuLi in THF gives the sulfonamide (III), which is condensed with the chloropurine (IV) by means of Pd[P(OPr)3]4 in THF or NMP to yield the adduct (V). The N-protection of the formamide group of (V) with Boc2O and NaH in THF affords compound (VI), which is reduced and deprotected with NaBH4 in methanol to provide the N-Boc protected chloropurine (VII). Finally, this compound is treated with hot HOAc to furnish the target chloropurine (VIII) (see schemes 14673102a intermediate (VIII), 14673103a intermediate (VIII), 14673104a intermediate (IX), 14673107a intermediate (XII), 14673111a intermediate (IX) and 14673113a intermediate (XIII)).