Highly functionalized dispiro oxindole-pyrrolo[1,2-c]thiazole-piperidone hybrid: Synthesis, characterization and theoretical investigations on the regiochemistry

• Published in: Journal of molecular structure 2016-10, Vol.1121, p.93-103
• Main Authors: Suresh Kumar, Raju, Almansour, Abdulrahman I., Arumugam, Natarajan, Soliman, Saied M., Ranjith Kumar, Raju, Ghabbour, Hazem A.
• Format: Article
• Language: English
• Subjects: 1,3-Dipolar cycloaddition; Azomethine ylide; Charge transfer; Cycloaddition; DFT; Dispiro; Electronics; FMO; Heterocycle; Mathematical analysis; Molecular mechanics; Molecular structure; NMR spectroscopy; Synthesis; X-rays
• ISSN: 0022-2860; 1872-8014
• DOI: 10.1016/j.molstruc.2016.05.061

The synthesis of highly functionalized dispiro oxindole–pyrrolo[1,2-c]thiazole–piperidone hybrid has been achieved regioselectively employing microwave-assisted three-component 1,3-dipolar cycloaddition. Structural elucidation of the compound has been accomplished using NMR spectroscopy and further confirmed by single crystal X-ray crystallographic studies. The molecular structure of the compound crystallized in monoclinic, P21/c, a = 11.6182 (2) Å, b = 12.2466 (2) Å, c = 21.7061 (3) Å, β = 103.018 (1)°, V = 3009.04 (8) Å3, Z = 4. The cycloaddition was found to proceed by normal electronic demand (NED) character with a significant high charge transfer (0.1247 eV) from the 1,3-dipole to the dipolarophile. The regiochemistry has been explained using the local reactivity descriptors obtained from the DFT calculations. The DFT optimized molecular structure agreed well with the X-ray results. [Display omitted] •Highly functionalized dispiro oxindole–pyrrolo[1,2-c]thiazole–piperidone hybrid has been achieved regioselectively.•Structure was accomplished using NMR spectroscopy and X-ray crystallographic studies.•The formation of product has been explained using the local reactivity descriptors obtained from the DFT calculations.•DFT optimized molecular structure agree well with the X-ray results.