title: Detailed 1H and 13C NMR structural assignment and relative stereochemistry determination for three closely related sesquiterpene lactones.
abstract: A complete analysis of (1)H and (13)C NMR spectra of the trypanocidal sesquiterpene lactone eremantholide C and two of its analogues is described. These structurally similar sesquiterpene lactones were submitted to (1)H NMR, (13)C {(1)H} NMR, gCOSY, gHSQC, gHMBC, J-resolved and DPFGSE-NOE NMR techniques. The detailed analysis of those results, correlated to some computational calculations (molecular mechanics), led to the total and unequivocal assignment of all (1)H and (13)C NMR data. The determination of all (1)H/(1)H coupling constants and all signal multiplicities, together with the elimination of previous ambiguities were also achieved.
authors: Departamento de Química, Centro de Ciências Exatas e de Tecnologia, Universidade Federal de São Carlos, Via Washington Luiz, km 235, 13565-905, São Carlos, SP, Brazil. heleno.vcg@unifran.br
authors: Vladimir Constantino Gomes
authors: VC
authors: Heleno
authors: Kleber Thiago
authors: KT
authors: de Oliveira
authors: João Luis Callegari
authors: JL
authors: Lopes
authors: Norberto Peporine
authors: NP
authors: Lopes
authors: Antonio Gilberto
authors: AG
authors: Ferreira
mesh_terms: D002247:Carbon Isotopes / Q000032:analysis / Q000737:chemistry; D007783:Lactones / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D011522:Protons; D012717:Sesquiterpenes / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D002247:Carbon Isotopes; D007783:Lactones; D011522:Protons; D012717:Sesquiterpenes