title: Isolation and synthesis of acmellonate, a new unsaturated long chain 2-ketol ester from Spilanthes acmella.
abstract: Paracress (Spilanthes acmella) is commonly used as a spice, e.g., in Madagascar. To get more information about the taste active compounds, Jambu oleoresin produced from Spilanthes acmella and extracts prepared directly from the plant were fractionated and the fractions were analysed and evaluated by tasting. In addition to the long known tingling compounds (2E,6Z,8E)-deca-2,6,8-trienoic acid N-isobutyl amide (spilanthol) and (2E,6Z,8E)-deca-2,6,8-trienoic acid N-(2-methylbutyl) amide, as a minor constituent also the new 2-ketol ester (7Z,9E)-2-oxo-undeca-7,9-dienyl 3-methylbut-2-enoate (acmellonate) was isolated. The structure of the latter compound was verified by total synthesis of the ketol ester via the reaction of tris(trimethylsilyloxy)ethene and (6Z,8E)-deca-6,8-dienoic acid chloride and subsequent classical esterification. Acmellonate shows a weak tingling and numbing effect on the tongue and contributes only to a small extend to the overall flavour of Jambu.
authors.affiliation: Symrise GmbH & Co. KG, Research & Development, PO Box 1253, 37603 Holzminden, Germany. jakob.ley@symrise.com
authors.forename: J P
authors.initials: JP
authors.lastname: Ley
authors.forename: M
authors.initials: M
authors.lastname: Blings
authors.forename: G
authors.initials: G
authors.lastname: Krammer
authors.forename: G
authors.initials: G
authors.lastname: Reinders
authors.forename: C-O
authors.initials: CO
authors.lastname: Schmidt
authors.forename: H-J
authors.initials: HJ
authors.lastname: Bertram
mesh_terms: D019659:Asteraceae / Q000737:chemistry*; D002208:Caproates / Q000737:chemistry; D004952:Esters / Q000138:chemical synthesis / Q000737:chemistry / Q000302:isolation & purification*; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D007659:Ketones / Q000138:chemical synthesis / Q000737:chemistry / Q000302:isolation & purification*; D009682:Magnetic Resonance Spectroscopy; D009943:Organophosphorus Compounds / Q000737:chemistry; D010936:Plant Extracts / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization; D017365:Spices; D013649:Taste
chemical_list: D002208:Caproates; D004952:Esters; D007659:Ketones; D009943:Organophosphorus Compounds; D010936:Plant Extracts; C018620:oleoresins; C061896:triphenylphosphine