Synthesis, characterization and DFT study of 4H-benzo[h]chromene derivatives

Interaction of 4-methoxy-1-naphthol (1) with α-cyano-p-chlorocinnamonitrile (2a) and ethyl α-cyano-p-chlorocinnamate (2b) provided 2-amino-4-(4-chlorophenyl)-6-methoxy-4H-benzo[h]chromene-3-carbonitrile (3a) and ethyl 2-amino-4-(4-chlorophenyl)-6-methoxy-4H-benzo[h]chromene-3-carboxylate (3b), respectively. Structures of these compounds were established on the basis of IR, UV, 1H NMR, 13C NMR, 13C NMR-DEPT and MS data. Moreover, imino tautomer (3b′) has been designed. Using density functional theory geometries have been optimized at B3LYP/6-31G* level of theory, the absorption spectra has been computed by using time dependant density functional theory at TD-B3LYP/6-31G* level of theory. Moreover, the absorption spectra in solvents have been computed and compared with experimental data. The highest occupied molecular orbitals, lowest unoccupied molecular orbitals and HOMO–LUMO energy gap of studied systems have been discussed.