NMR assignments and X-ray diffraction spectra for two unusual kaurene diterpenes from Erythroxylum barbatum.
The structural characterization of two new, unusual kaurene diterpenes isolated from roots of Erythroxylum barbatum is described. 1D NMR and several 2D shift-correlated NMR pulse sequences (1H,1H-COSY, HMQC, HMBC and NOESY) were used for structure elucidation and the unambiguous 1H and 13C chemical shifts assignments. Single crystal X-ray diffraction analysis was also used to confirm the final relative configuration of the compounds possessing the C-20 methyl and the CH2-15 methylene groups in cis-orientation.
dos Santos
Claudio Costa
CC
Curso de Pós-Graduação em Química Orgânica, Departamento de Química Orgânica e Inorgânica, Centro de Ciências, Universidade Federal do Ceará, CP 12 200, Fortaleza-CE, 60451-970, Brazil.
Sousa Lima
Mary Anne
MA
Braz-Filho
Raimundo
R
de Simone
Carlos Alberto
CA
Silveira
Edilberto Rocha
ER
D045786:Diterpenes, Kaurane / Q000737:chemistry*; D030921:Erythroxylaceae / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008968:Molecular Conformation; D014961:X-Ray Diffraction
D045786:Diterpenes, Kaurane; C002627:kaurene