- Cassis and Green Tea: Spontaneous Release of Natural Aroma Compounds from β-Alkylthioalkanones
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In depth headspace analysis of the slow degradation of β-alkylthioalkanones in ambient air led to the discovery of a novel δ-cleavage pathway, by which β-mercaptoketones are released. Since β-mercaptoketones are potent natural aroma compounds occurring in many fruits, herbs and flowers, the discovery of an enzyme-independent molecular precursor for this class of high-impact molecules is of practical importance. Moreover, the formation of β-diketones and aldehydes by concomitant oxidation at the α-sulfur-position enhances the versatility of this class of aroma precursors. A mechanistic model is proposed which suggests that the oxidative degradation occurs through a novel Pummerer-type rearrangement of initially formed persulfoxides.
- B?ttig, Sarah,Egger, Timothy,Gey, Olga,Bochet, Christian G.,Flachsmann, Felix
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- Environment-friendly method for synthesizing propenyl ketone compound
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The invention discloses an environment-friendly method for synthesizing a propenyl ketone compound. The method comprises the following steps: subjecting an aldehyde compound and allyl bromide to a Barbier reaction in the presence of metal powder, so as to obtain an allyl alcohol compound; and subjecting the allyl alcohol compound to a structural isomerization reaction in the presence of a catalyst, thereby obtaining the propenyl ketone compound. The method disclosed by the invention has the advantages of short synthesis route, mild reaction conditions, simplicity in operation, readily available raw materials, and the like and has relatively high academic research value and market economy significance.
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Paragraph 0019; 0023
(2019/01/04)
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- 172. β-Cleavage of Bis(homoallylic) Potassium Alkoxides. Two-Step Preparation of Propenyl Ketones from Carboxylic Esters. Synthesis of ar-Turmerone, α-Damascone, β-Damascone, and β-Damascenone
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The transformation of 36 bis(homoallylic) alcohols VII to alkenones IX and X via β-cleavage of their potassium alkoxides VIIa in HMPA has been investigated (cf.Scheme 2).These studies have established an order of β-cleavage for 2-propenyl, 1-methyl-2-propenyl, 2-methyl-2-propenyl, 1,1-dimethyl-2-propenyl, and benzyl groups in alkoxides 49a-56a and have allowed a comparison between the β-cleavage reaction and the oxy-Cope rearrangement in alkoxides 74a-83a.As illustrative synthetic applications, a two-step preparation of propenyl ketones 15-42 from carboxylic esters is described, together with syntheses of ar-turmerone (48), α-damascone ((E)-71), β-damascone ((E)-109), and β-damascenone ((E)-111).
- Snowden, Roger L.,Linder, Simon M.,Muller, Bernard L.,Schulte, Karl H.
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p. 1858 - 1878
(2007/10/02)
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- Use of 5-methyl-hept-2-en-4-one as a fragrance and/or flavor
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A perfumed or edible composition comprising an appropriate carrier and an amount of 5-methyl-hept-2-en-4-one effective to impart its fragrance or flavor to the composition. It imparts a fragrance and flavor reminiscent of hazelnut.
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