Formation of fused azetinones by photolysis and pyrolysis of triazinones. N-aminonaphth[2,3-b]azet-2(1H)-one and N-1-adamantylbenzazet-2-(1H)-one

Abstract

N-Aminonaphth[2,3-b]azet-2(1H)-one (4b) has been isolated as a labile crystalline solid from the photolysis of 3-aminonaphtho[2,3-d]-v-triazin-4(3H)-one (3b) in acetonitrile. When heated or when treated with acetic acid, the azetinone is converted into benz[f]indazol-3(2H)-one (7). Oxidation of (4b) by lead tetra-acetate gives 2-naphthoic acid. Photolysis or pyrolysis of 3-amino-1,2,3-benzotriazin-4(3H)-one (1a) gives the indazolinone (6) directly. 3-(1 -Adamantyl)-1,2,3-benzotriazin-4(3H)-one (1b) is resistant to photochemical cleavage, but at 600° in the vapour phase it undergoes two competing fragmentations. N-1-Adamantylbenzazetinone (2b) is formed in the major reaction, and adamantyl isocyanate and biphenylene are produced in the minor reaction.