Photo- and thermochromic 2-amino-2H-chromenes
A number of N-aryl- and N-alkylimines of 2-hydroxy-5,6-benzocinnamaldehyde were synthesized. The cyclic 2-amino-2H-chromene structure in nonpolar solvents was established for them by IR, UV, and PMR spectroscopy. It is shown that the transition to polar solvents leads to the establishment of a tautomeric ring-chain equilibrium. The equilibrium thermal transformations and phototransformations of some N-aryl- and N-alkylimines were studied.