Synthesis and spectrokinetic studies of a new family of thiophenic [2H]-chromens

A series of methyl 8,9-dimethoxy-2,2-diaryl-6-(2′-thienyl)-2H-naphtho[1,2-b]pyran-5-carboxylates were obtained from 1-hydroxy-3-methoxycarbonyl-4-(2′-thienyl)-6,7-dimethoxynaphthalene. The photochromic properties of this new family of 2H-naphtho[1,2-b]pyrans were studied under continuous irradiation and compared to those of reference's compounds. All the studied molecules appeared to have a better colourability and in some cases interesting ring closure kinetic constant (kΔ).