Benzindazoles from triketones of the indan series

In the reaction of 2-acetonyl-and 2-phenacyl-2-phenylindan-1, 3-diones with hydrazine hydrate, the five-membered ring of the indandione system isomerizes into a six-membered ring forming derivatives of 5-hydroxy-1H-benzg]indazole. Derivatives of 3,4-(CO)-benzoylenepyridazine have been isolated as intermediates. The benzindazoles mentioned have been obtained by independent synthesis from the corresponding 2-acyl-1, 4-dihydroxynaphthalenes.For part I, see 1].