3,3-Diphenyl-3H-naphthopyran
3,3-Diphenyl-3H-naphthopyran is an organic compound that is the parent of several related naphthopyrans. This family of compounds are used as photochromic dyes in ophthalmic glasses. The compound is a colorless solid.
Synthesis and reactions
The synthesis of naphthopyrans starts with 2-naphthol.Upon exposure to UV-radiation, the pyran ring opens. The products, "photomerocyanines", are yellow to red dark colored.