Synthesis and reactivity of formyl-substituted photochromic 3,3- diphenyl-[3H]-naphtho[2,1-b]pyrans

Article abstract of DOI:10.1016/S0040-4020(99)00245-8

Synthetic accesses to formylated photochromic 3,3-diphenyl-[3H]- naphthopyrans (or 2H-benzochromenes) are developed through classical cyclization between appropriate hydroxynaphthaldehydes and 1,1- diphenylpropyne-1-ol and also via substituent transformations on the naphthopyran skeleton including bromine/lithium exchange and the oxidation of an hydroxymethyl group. Examples of formyl group reactivity (Wittig and Knoevenagel reactions, imine formation) from these compounds are given, showing their interest in the subsequent preparation of supramolecular systems involving a photoreactive entity.