Abstract
Highly functionalized spirooxindole-pyrrolidine hybrids have been synthesized stereoselectively through a [3 + 2] cycloaddition strategy in an ionic liquid, 1-butyl-3-methylimidazolium bromide ([bmim]Br). The structure of these spiro heterocyclic hybrids was elucidated using one and two dimensional NMR spectroscopy, single crystal X-ray crystallographic studies and Density Functional Theory (DFT) calculations. The calculated geometric parameters are in good agreement with the experimental data obtained from the X-ray structures. The Natural Bond Orbital (NBO) calculations on these molecules confirm the electron rich carbonyl oxygen and electron deficient NH groups. The 1H and 13C NMR chemical shifts calculated using GIAO method are in good agreement with the experimental data. The DFT computed polarizability values also suggest the possible NLO activity of these molecules.
Stereoselective green synthesis of new spirooxindole-pyrrolidine hybrids 4 and 6 were synthesized and their structures were confirmed by NMR spectra, X-ray crystallography and DFT studies. The DFT computed polarizability values suggest the possible NLO property of the synthesized compounds. [Display omitted]
•Highly functionalized spirooxindole-pyrrolidine hybrid heterocycles 4 &6 were synthesized using an ionic liquid, 1-butyl-3-methylimidazolium bromide ([bmim]Br).•The molecular structures of these heterocyclic hybrids were confirmed from X-ray crystallographic studies, 1D & 2D NMR spectroscopy and DFT (B3LYP/6-31G[d,p]) studies.•The DFT computed bond parameters, NMR chemical shifts and reactive sites are in good agreement with experimental findings.•The DFT computed polarizabilities suggest the possible NLO properties of the compounds 4 and 6.