title: Isolation and identification of two novel compounds from Marsdenia roylei and their quantum chemical calculations.
abstract: Two new compounds 1 (Methyl 26-di-deoxy-6-methyl-β-D-allohexopyranoside) and 3 (3, 11, 12, 20 tetra-O-acetyl-pregn-5-ene-14β-ol) have been isolated from the chloroform-soluble extract of the whole plant of Marsdenia roylei (family: Asclepiadaceae) and their structures were determined by 1D, 2D NMR and ESI-MS as well as by chemical modification. We have calculated the molecular geometries, local reactivity descriptors by the density functional theory with B3LYP functional with basis set 6-311G+(d,2p) of 1, 3 and 4 (deacylated 3). The1H and13C NMR chemical shifts of 1, 3 and 4 were calculated using Gauge-Including Atomic Orbital approach and these values are correlated with the experimental observations.
authors.affiliation: a Department of Chemistry , University of Lucknow , Lucknow , India.
authors.forename: Mukul R
authors.initials: MR
authors.lastname: Gupta
authors.affiliation: a Department of Chemistry , University of Lucknow , Lucknow , India.
authors.forename: Alok
authors.initials: A
authors.lastname: Kumar
authors.affiliation: a Department of Chemistry , University of Lucknow , Lucknow , India.
authors.forename: Naveen K
authors.initials: NK
authors.lastname: Khare
mesh_terms: D000215:Acylation; D002725:Chloroform / Q000737:chemistry; D005960:Glucosides; D009682:Magnetic Resonance Spectroscopy; D031101:Marsdenia / Q000737:chemistry*; D008958:Models, Molecular; D015394:Molecular Structure; D010936:Plant Extracts / Q000737:chemistry; D011283:Pregnenes; D011789:Quantum Theory; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: C000618917:3,11,12,20 tetra-O-acetyl-pregn-5-ene-14beta-ol; D005960:Glucosides; D010936:Plant Extracts; D011283:Pregnenes; C000618916:methyl 26-di-deoxy-6-methyl-beta-D-allohexopyranoside; D002725:Chloroform
keywords: Asclepiadaceae; Marsdenia roylei; density functional theory; pregnane derivatives; spectroscopic analysis