title: Antimalarial 5,6-Dihydro-α-pyrones from Cryptocarya rigidifolia: Related Bicyclic Tetrahydro-α-Pyrones Are Artifacts1.
abstract: Antimalarial bioassay-guided fractionation of an EtOH extract of the root wood of Cryptocarya rigidifolia (Lauraceae) led to the isolation of the five new 5,6-dihydro-α-pyrones cryptorigidifoliols A-E (1-5) and the six bicyclic tetrahydro-α-pyrone derivatives cryptorigidifoliols F-K (6-11). The structure elucidations of all compounds were made on the basis of the interpretation of spectroscopic data and chemical derivatization, and the relative and absolute configurations were determined by NOESY, electronic circular dichroism (ECD), and (1)H NMR analysis of α-methoxyphenylacetyl (MPA) derivatives. The bicyclic tetrahydro-α-pyrone derivatives were identified as products of acid-catalyzed intramolecular Michael addition of the 5,6-dihydro-α-pyrones in the presence of silica gel. A structure-activity relationship study suggested that the presence of an α,β-unsaturated carbonyl moiety is not essential for potent antimalarial activity.
authors.affiliation: †Department of Chemistry and the Virginia Tech Center for Drug Discovery, Virginia Tech, M/C 0212, Blacksburg, Virginia 24061, United States.
authors.forename: Yixi
authors.initials: Y
authors.lastname: Liu
authors.affiliation: †Department of Chemistry and the Virginia Tech Center for Drug Discovery, Virginia Tech, M/C 0212, Blacksburg, Virginia 24061, United States.
authors.forename: L Harinantenaina
authors.initials: LH
authors.lastname: Rakotondraibe
authors.affiliation: †Department of Chemistry and the Virginia Tech Center for Drug Discovery, Virginia Tech, M/C 0212, Blacksburg, Virginia 24061, United States.
authors.forename: Peggy J
authors.initials: PJ
authors.lastname: Brodie
authors.affiliation: ‡Department of Biochemistry and the Virginia Tech Center for Drug Discovery, Virginia Tech, M/C 0308, Blacksburg, Virginia 24061, United States.
authors.forename: Jessica D
authors.initials: JD
authors.lastname: Wiley
authors.affiliation: ‡Department of Biochemistry and the Virginia Tech Center for Drug Discovery, Virginia Tech, M/C 0308, Blacksburg, Virginia 24061, United States.
authors.forename: Maria B
authors.initials: MB
authors.lastname: Cassera
authors.affiliation: §Missouri Botanical Garden, P.O. Box 299, St. Louis, Missouri 63166, United States.
authors.forename: James S
authors.initials: JS
authors.lastname: Miller
authors.affiliation: ⊥Missouri Botanical Garden, Lot VP 31 Ankadibevava, Anjohy Antananarivo 101, Madagascar.
authors.forename: F
authors.initials: F
authors.lastname: Ratovoson
authors.affiliation: ∥Centre National d'Application des Recherches Pharmaceutiques, B.P. 702, Antananarivo 101, Madagascar.
authors.forename: Etienne
authors.initials: E
authors.lastname: Rakotobe
authors.affiliation: ∥Centre National d'Application des Recherches Pharmaceutiques, B.P. 702, Antananarivo 101, Madagascar.
authors.forename: Vincent E
authors.initials: VE
authors.lastname: Rasamison
authors.affiliation: †Department of Chemistry and the Virginia Tech Center for Drug Discovery, Virginia Tech, M/C 0212, Blacksburg, Virginia 24061, United States.
authors.forename: David G I
authors.initials: DG
authors.lastname: Kingston
mesh_terms: D000962:Antimalarials / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D002942:Circular Dichroism; D031369:Cryptocarya / Q000737:chemistry*; D018360:Crystallography, X-Ray; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D011753:Pyrones / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D013329:Structure-Activity Relationship
chemical_list: D000962:Antimalarials; D011753:Pyrones