title: A new longipinene diester from Stevia monardifolia Kunth.
abstract: Nonpolar and medium polarity fractions from whole plant methanolic extracts of Stevia monardifolia afforded the new 7beta-angeloyloxy-8alpha-isovaleroyloxylongipin-2-en-1-one 1 along with known 7beta,8alpha-diangeloyloxylongipin-2-en-1-one 2 and 7beta,8alpha-diangeloyloxylongipinan-1-one 3. Alkaline hydrolysis of a mixture of 1 and 2 gave 7beta,8alpha-dihydroxylongipin-2-en-lone 4 which was subjected to a single crystal X-ray diffraction study. The new compound 1, which is the third 7beta,8alpha-dihydroxylongipin-2-en-1-one diester natural product isolated from a Stevia especies, was fully characterized by one- and two-dimensional NMR spectroscopy and its absolute configuration was confirmed as the 4R,5S,7S,8S,10R,11R enantiomer by vibrational circular dichroism (VCD) measurements in comparison to calculation at the B3LYP/DGDZVP level of theory.
authors.affiliation: Departamento de Química Orgánica, Escuela Nacional de Ciencias Bioldgicas, Instituto Politécnico Nacional, Prolongación de Carpio y Plan de Ayala, Col. Santo Tomas, DF México, 11340 Mexico.
authors.forename: Rodrigo E
authors.initials: RE
authors.lastname: Rojas-Pérez
authors.forename: Ernestina
authors.initials: E
authors.lastname: Cedillo-Portugal
authors.forename: Pedro
authors.initials: P
authors.lastname: Joseph-Nathan
authors.forename: Eleuterio
authors.initials: E
authors.lastname: Burgueño-Tapia
mesh_terms: D008958:Models, Molecular; D015394:Molecular Structure; D012717:Sesquiterpenes / Q000737:chemistry*; D036625:Stevia / Q000737:chemistry*
chemical_list: D012717:Sesquiterpenes; C410907:longipinene