The overall synthetic approach to N-0861 is described in Scheme 17807901a: Reduction of 4,6-dichloro-5-nitropyrimidine (I) followed by reaction with methylamine gives 5-amino-6-chloro-4-methylaminopyrimidine (III). Cyclization with triethylorthoformate under acidic conditions results in 9-methyl-6-chloropurine (IV). Reaction of (?-endo-2-aminonorbornane (V) with 9-methyl-6-chloropurine (IV) provides N-0861.