Reactions of spiro-indazoles containing keto-groups. Syntheses of benz[a]aceanthrylenes, naphth[2,1-a]aceanthrylenes, and fluoranthenes

Abstract

Anthrone-10-spiro-3′-3′H-indazole (1) and 3H-indazole-3-spiro-1′-naphthalen-4′(1′H)-one (3), prepared by the cycloaddition of benzyne with 10-diazoanthrone (6) and 4-diazonaphthalen-1(4H)-one (7), respectively, thermally rearranged with elimination of nitrogen to 8-hydroxybenz[a]aceanthrylene (9b) and 3-hydroxyfluoranthene (11b), respectively. The diazoketone (6) reacted with 1,2-naphthyne to give anthrone-10-spiro-3′3′H-benz[g]indazole (4) and anthrone-10-spiro-1′-1′H-benz[e]indazole (5), which gave the rearrangement product, 10-hydroxynaphth [2,1-a]aceanthrylene (12b) by thermolysis. Photolysis of the spiro-indazoles afforded the rearrangement and/or photo-oxidation products. Thermolysis and photolysis are accountable on the basis of formation of biradicals [(14), (18), (19), and (21)] and isomerization of these to fused polycyclic compounds. In particular, the isomerization of the biradical (21) to (12b) involves the formation of the naphtho[a]cyclopropene (20).