Preparation and photochromic properties of 2,3-bisarylbenz[f]indenones

From 2,3-dibromobenz[f]indenone, four compound: 2,3-bis(5-methyl-2-phenyl-4-thiazolyl)benz[f]indenone 1O, 2,3-bis(3,5-dimethyl-4-isoxazolyl)benz[f]indenone 2O, 3-(3,5-dimethyl-4-isoxazolyl)-2-(5-methyl-2-phenyl-4-thiazolyl)benz[f]indenone 3O and 2,3-bis(5-methyl-2-phenyl-4-thiazolyl)benz[f]indenol 4O were prepared, and their photochromic properties were investigated. Among them, photochrome 1O (weak photochromic) and its bisthiazolylbenz[f]indenol derivative 4O displayed photochromism. During ring closure photoreaction, photochrome 4O showed high conversion ratio (98.4%) with low diastereomeric excess (38%).