One-Pot Synthesis and Computational Investigation of New Bioactive Chromene Derivatives

1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU) was used as a mild and efficient catalyst for synthesis of various dihydropyrano[3,2-c]chromene-3-carboxylate derivatives via one-pot, three-component condensation of aromatic aldehydes, active methylene and 4-hydroxycoumarin in ethanol under reflux. The distinctive features of this process are mild reaction conditions, reusability of the reaction media, short reaction time, easy isolation of products and good yield. In addition, the effect of electron donating and withdrawing groups on the reactivity of chromene derivatives was investigated and evaluated by quantum chemical tools. For this purpose, the FMO analyses were performed and considered in terms of the new perspectives of the C-DFT. Also, the NBO analyses of the chromene derivatives were conducted to look for and compare the resonance and inductive effect on the possible reactivity behaviors.