Synthetic approaches to anthrazulenes and synthetic approaches to polycyclic compounds via macrocyclic sulphur compounds

Abstract

The existence of the azulenes The existence of the azulenes has served as an incentive in the search for such analogus compounds as pentalene and heptalene. In the azulene series, 1, 2-benzazulene (2), 5, 6-benzazulen (3) and trinitrobenzene complex of 4, 5-benzazulene (4) are known. However all efforts to synthesize anthrazulene (cyclohept-[f]-indene)(5)derivatives have been unsuccessful. It was also concluded that cyclohept-[f]-indene has little if any inherent aromatic character. The synthesis of a partially hydrogenated derivative of a benzo-analogue of anthrazulene (5), cyclohepta[b] fluorene (6) has been reported.