Photochemistry of some 2,5-substituted tropone mesogens

The photoreactivity of three 2-acyloxy-5-alkoxytropone derivatives, two of which are known to show thermotropic liquid crystalline phases, has been studied with the aim of finding photoresponsive mesogenic materials. The irradiation of solutions of these compounds in CH,CN under air atmosphere brings to endoperoxides which do not show mesomorphism and are not fully reversible to their respective precursors neither photochemically nor thermally. From the chemical point of view, the facile and relatively neat formation of endoperoxides open synthetic routes to new functionalized tropone derivatives. (C) 1998 Elsevier Science S.A. All rights reserved.