Polycyclic N ‐Heterocyclic Compounds, Part 72: Reaction of N ‐([1]Benzofuro (or Benzothieno)[3,2‐ d ]pyrimidin‐4‐yl)formamidine and N ‐(Pyrido[2,3‐ d ]pyrimidin‐4‐yl)formamidine Derivatives with Hydroxylamine Hydrochloride

The reactions of N ‐([1]benzofuro[3,2‐ d ]pyrimidin‐4‐yl)formamidines with hydroxylamine hydrochloride gave rearranged cyclization products via ring cleavage of the pyrimidine component accompanied by a ring closure of the 1,2,4‐oxadiazole to give N ‐[2‐([1,2,4]oxadiazol‐5‐yl)[1]benzofuran‐3‐yl)formamide oximes. N ‐([1]Benzothieno[3,2‐ d ]pyrimidin‐4‐yl)formamidines and N ‐(pyrido[2,3‐ d ]pyrimidin‐4‐yl)formamidines with hydroxylamine hydrochloride gave similar results.