Nucleophilic radical substitution of polychloroazines

Polychloroazines (1-6) are susceptible to homolytic chlorine substitution by alkyl radicals. In general, the chlorine at the ortho-position to the ring nitrogen is readily replaced by an alkyl radical like adamantyl and tert-butyl. However, the chlorine at the C₂-position of pyrimidine did not show any sign of the radical substitution. The reactivity decreases in the order of adamantyl, tert-butyl, and isopropyl radicals.