title: Molecular structure, vibrational and 13C NMR spectra of two ent-kaurenes spirolactone type diterpenoids rabdosinate and rabdosin B: a combined experimental and density functional methods.
abstract: The title compounds, rabdosinate and rabdosin B, were isolated from the leaves of Isodon japonica, and characterized by IR-NMR spectroscopy. The molecular geometry, vibrational frequencies and gauge including atomic orbital (GIAO-13C) chemical shift values of the title compounds have been calculated by using DFT/B3LYP method with 6-311++G(d,p) basis set. In addition, obtained results were related to the linear regression of experimental 13C NMR chemical shifts values. The integral equation formalism polarized continuum model (IEFPCM) was used in treating chloroform solvation effects on optimized structural parameters and 13C chemical shifts. Besides, molecular electrostatic potential (MEP), HOMO-LUMO analysis were performed by the B3LYP method.
authors.affiliation: Department of Chemistry and Chemical Engineering, Heze University, Heze 274015, PR China. Electronic address: chemistry@vip.qq.com.
authors.forename: Tao
authors.initials: T
authors.lastname: Wang
authors.affiliation: Department of Chemistry and Chemical Engineering, Heze University, Heze 274015, PR China.
authors.forename: Xueliang
authors.initials: X
authors.lastname: Wang
mesh_terms: D066241:Carbon-13 Magnetic Resonance Spectroscopy; D004224:Diterpenes / Q000737:chemistry*; D045786:Diterpenes, Kaurane / Q000737:chemistry*; D004583:Electrons; D008958:Models, Molecular; D008968:Molecular Conformation; D011789:Quantum Theory; D017550:Spectroscopy, Fourier Transform Infrared; D013148:Spironolactone / Q000737:chemistry*; D055672:Static Electricity; D013816:Thermodynamics; D014732:Vibration
chemical_list: D004224:Diterpenes; D045786:Diterpenes, Kaurane; C000598712:rabdosinate; D013148:Spironolactone; C037018:rabdosin B
keywords: 6,7-Seco-ent-kaurenes spirolactone type diterpenoids; DFT; Frontier molecular orbitals; Molecular electrostatic potential