Chemical reactivity, molecular structure, spectroscopic and DFT computational studies of spiro-heterocycle incorporating furan ring

Spiro-heterocycle derivative was prepared by reaction of dienone derivative with active methylene heterocycle pyrimdine-trione derivative in DCM mediated by diethyl amine as base. The X-ray structure of the dienone and target compound were determined and the chemical reactivity of the reactants were investigated using DFT B3LYP/6-311G(d,p) calculations. The reaction could proceed only in the presence of diethylamine as base. In addition, the molecular structure and physico-properties of the desired target were computed and the calculated structure agreed well with the experimental data. The atomic charges and the stabilization energy due to the intramolecular charge delocalization processes were calculated using NBO method. The small LP(2)O4 -> BD*(1)C22-H38 (0.66 kcal/mol) and LP(2)05 -> BD*(1)C23-H40 (0.68 kcal/mol) stabilization energies (E(2)) indicated that the C-H-O interactions are weak. Based on the TD-DFT results, the studied molecule showed five intense electronic transition bands. The longest wavelength and most intense electronic transition band at 242.7 nm (exp. 231 nm) are due to H-2/H -> L+ 1 excitations. The higher polarizability and lower energy gap of the studied compound indicate its better NLO material than urea.