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(1 H )‐pyrazolo[5,1‐ c ][1,2,4]triazines]

The reactions of the 3‐substituted 4‐amino‐8‐ethoxycarbonyl[5,1‐ c ][1,2,4]triazines 1 and 2 with o ‐amino‐phenol hydrochloride gave the pyrazolo[1′,5′:3,4][1,2,4]triazino[5,6‐ b ][1,5]benzoxazepines 5 and 8 . The alkylation of 5 with methyl iodide and isopropyl iodide afforded the 6‐alkoxylpyrazolo[1′,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 spiro[benzoxazole‐2′(3′ H ),4(1 H )pyrazolo[5,1‐ c ][1,2,4]‐triazines] 7a, 7b and 9 . The screening data of the above compounds was described.