Synthesis, crystal structure, conformational analysis, nonlinear optical property and computational study of novel pregnane derivatives

The molecular structure and detailed spectroscopic analysis of some novel newly synthesized pregnane derivatives have been performed using experimental techniques like H-1, C-13 NMR, NOESY, FT-IR, UV-visible spectroscopy, mass spectrometry, crystallography, as well as theoretical calculations. The structure and stereochemistry of 3 beta-benzoyloxy 16 alpha-methoxy pregn-5-ene-20-one (3) has been confirmed by single crystal X-ray diffraction, which crystallized in orthorhombic form having P2(1)2(1)2(1) space group with unit cell parameters a = 6.395(5) angstrom, b = 19.872(17) angstrom, c = 19.898(16) angstrom and Z = 4. Quantum chemical calculations have been performed by density functional theory (DFT) using B3LYP functional and 6-31G (d,p) basis set. The electronic properties such as frontier orbitals and band gap energies have been calculated using time dependent density functional theory (TD-DFT). The strength and nature of weak intramolecular interactions have been studied by AIM approach. The vibrational wavenumbers have been calculated using DFT method and assigned with the help of potential energy distribution (PED). Global and local reactivity descriptors have been computed to predict reactivity and reactive sites in the molecule. First hyperpolarizability values have been calculated to describe the nonlinear optical (NLO) property of the synthesized compounds. Molecular electrostatic potential (MEP) analysis has also been carried out. (C) 2015 Elsevier B.V. All rights reserved.