Ring transformation of 1,5-benzoxazepines into spirobenzoxazoles. Synthesis of pyrazolo[1′,5′:3,4][1,2,4]triazino-[5,6-b][1,5]benzoxazepines and spiro[benzoxazole-2′(3′H),4(1H)-pyrazolo[5,1-c][1,2,4]triazines]

The reactions of the 3-substituted 4-amino-8-ethoxycarbonyl5,1-c]1,2,4]triazines 1 and 2 with o-amino-phenol hydrochloride gave the pyrazolo1′,5′:3,4]1,2,4]triazino5,6-b]1,5]benzoxazepines 5 and 8 . The alkylation of 5 with methyl iodide and isopropyl iodide afforded the 6-alkoxylpyrazolo1′,5′:3,4]1,2,4]triazino-5,6-b]1,5]benzoxazepines 6a and 6b , respectively. Refluxing of 5, 6a, 6b and 8 in hydrochloric acid/acetic acid resulted in ring transformation to produce the spirobenzoxazole-2′(3′H),4(1H)pyrazolo5,1-c]1,2,4]-triazines] 7a, 7b and 9 . The screening data of the above compounds was described.