title: 6-Alkyl-3,4-dihydro-2H-pyrans: chemical secretion compounds in neotropical harvestmen.
abstract: The defensive secretions of five neotropical species of harvestmen (Opiliones: Gonyleptidae) from the Brazilian Atlantic Forest were analyzed and chemically characterized by GC-MS and NMR methods. Three of the species, Cobania picea, Roweria virescens, and Serracutisoma proximum, secrete a mixture of 2,3-dimethyl-1,4-benzoquinone and 2-ethyl-3-methyl-1,4-benzoquinone. The secretions produced by the other two species, Iporangaia pustulosa and Neosadocus maximus, contain 1-hepten-3-one, 5-methyl-1-hexen-3-one, and 1-(6-butyl-3,4-dihydro-2H-pyran-2-yl)pentanone (1) as major components, as well as 2,3-dimethyl-1,4-benzoquinone and 2-ethyl-3-methyl-1,4-benzoquinone as minor constituents. The dihydropyran 1-(6-butyl-3,4-dihydro-2H-pyran-2-yl)pentanone (1) is a new natural product, composed of two 1-hepten-3-one subunits formally linked in a hetero-Diels-Alder reaction. The natural product was proven to be racemic, and its biogenetic origin is discussed.
authors.affiliation: Chemistry Institute, State University of Campinas, POB 6154 13083-970 Campinas, SP, Brazil.
authors.forename: Daniele F O
authors.initials: DF
authors.lastname: Rocha
authors.forename: Kerry
authors.initials: K
authors.lastname: Hamilton
authors.forename: Caroline C S
authors.initials: CC
authors.lastname: Gonçalves
authors.forename: Glauco
authors.initials: G
authors.lastname: Machado
authors.forename: Anita J
authors.initials: AJ
authors.lastname: Marsaioli
mesh_terms: D000818:Animals; D001097:Arachnida / Q000737:chemistry*; D001938:Brazil; D008401:Gas Chromatography-Mass Spectrometry; D008297:Male; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D010422:Pentanones; D011714:Pyrans / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D012543:Scent Glands / Q000378:metabolism; D013237:Stereoisomerism
chemical_list: C559013:1-(6-butyl-3,4-dihydro-2H-pyran-2-yl)pentanone; D010422:Pentanones; D011714:Pyrans