title: Absolute configuration of the alpha-methylbutyryl residue in longipinene derivatives from Stevia pilosa.
abstract: The absolute configuration of the alpha-methylbutyryl residue in (4R,5S,7S,8S,9S,10R,11R,2''S)-7-angeloyloxy-9-hydroxy-8-(alpha-methylbutyryloxy)-longipin-2-en-L-one and (4R,5S,7S,8R,10R,11R,2''S)-7-angeloyloxy-8-(alpha-methylbutyryloxy)- longipin-2-en-L-one was determined by chemical correlation with (S)-(+)-benzyl alpha-methylbutyrate prepared from authentic (S)-(+)-alpha-methylbutyric acid. Both compounds were isolated from the hexane extracts of roots of Stevia pilosa Lag. together with four other longipinene derivatives. The developed correlation method is useful to ascertain the chirality of natural alpha-methylbutyryl esters found in nature and to reinforce the hypotheses on the biogenetic origin of these residues.
authors.affiliation: Centro de Investigaciones Químicas, Universidad Autónoma del Estado de Hidalgo, Apartado 1-622, Pachuca, Hidalgo 42001, Mexico.
authors.forename: Rocío
authors.initials: R
authors.lastname: Alvarez-García
authors.forename: J Martín
authors.initials: JM
authors.lastname: Torres-Valencia
authors.forename: Luisa U
authors.initials: LU
authors.lastname: Román
authors.forename: Juan D
authors.initials: JD
authors.lastname: Hernández
authors.forename: Carlos M
authors.initials: CM
authors.lastname: Cerda-García-Rojas
authors.forename: Pedro
authors.initials: P
authors.lastname: Joseph-Nathan
mesh_terms: D008968:Molecular Conformation; D015394:Molecular Structure; D018517:Plant Roots / Q000737:chemistry; D012717:Sesquiterpenes / Q000737:chemistry* / Q000302:isolation & purification*; D036625:Stevia / Q000737:chemistry*
chemical_list: C501186:(4R,5S,7S,8R,10R,11R,2''S)-7-angeloyloxy-8-(alpha-methylbutyryloxy)- longipin-2-en-L-one; C501185:(4R,5S,7S,8S,9S,10R,11R,2''S)-7-angeloyloxy-9-hydroxy-8-(alpha-methylbutyryloxy)-longipin-2-en-L-one; D012717:Sesquiterpenes; C410907:longipinene