SYNTHESIS AND PHOTOCHROMIC BEHAVIOR OF NAPHTHOPYRANS, PYRANOQUINOLINES, PYRANOQUINAZOLINES AND PYRANOQUINOXALINES

New chromenes annulated with different six-membered azaheterocycles we re prepared, i.e., the 3H-pyrano[3,2-f]quinolines 9/10 and 14, the 8H- pyrano[2,3-h]isoquinoline 11, the 8H-pyrano[3,2-f]quinazoline 12, the 8H-pyrano[3,2-f]quinoxaline 13, and the 2H-pyrano[2,3-f]isoquinoline 1 5. The synthesis was achieved using conveniently substituted alpha,bet a-unsaturated aldehydes and organotitanium intermediates arising from azaheterocyclic phenols. Their photochromic behaviour (photocolouratio n yield, UV/VIS spectrum of photomerocyanines, rate constant of therma l bleaching) were studied besides those of corresponding naphthopyrans . The heterocycle effect and the role of substituents in the pyran moi ety were investigated quantitatively through the study of the photochr omic properties and the solvent effects. Diaryl-substituted azino-fusd chromenes, especially isoquinoline derivatives, exhibit increased col ourabilities and bathochromically shifted spectra for photomerocyanine s which open up new prospects for photochromic applications.