- Synthesis, olfactory evaluation and determination of the absolute configuration of the β- and γ-Iralia isomers
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The regioselective synthesis of the methyl-ionone isomers 6-9 is described. The enantiomers of the γ-isomers 8 and 9 are prepared by enzyme-mediated resolution of the corresponding 4-hydroxy derivatives followed by reductive elimination of the hydroxy group. The absolute configuration of the latter compound is determined by chemical correlation with the known α-isomers. Since all the isomers obtained are components of the artificial violet odourants sold under the trade name of Iralia, their odour properties are evaluated by professional perfumers.
- Barakat, Assem,Brenna, Elisabetta,Fuganti, Claudio,Serra, Stefano
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experimental part
p. 2316 - 2322
(2009/04/11)
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- The enantiomers of Iralia: preparation and odour evaluation
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The enantiomers of methyl ionones 1 and 2 were prepared by an enzyme-catalysed approach. Their odour properties were evaluated by skilful perfumers.
- Abate, Agnese,Brenna, Elisabetta,Fuganti, Claudio,Malpezzi, Luciana,Serra, Stefano
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p. 1145 - 1153
(2008/02/10)
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- CONTINUOUS PROCESS FOR PRODUCING PSEUDOIONONES AND IONONES
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The invention relates to a continuous process for producing pseudoionones of general formulas (I) and (I′) as well as isomers thereof, whereby: R1represents CH3 or (a); R2 and R3 represent hydrogen, CH3 or C2H5, and; R4 and R5represent hydrogen or CH3. These pseudoionones are produced by reacting an aldehyde of formula (II) with an excess of a ketone of general formula (III), whereby R1, R2 and R3 have the aforementioned meanings, in the presence of water and alkali hydroxide at an increased temperature and in a homogeneous solution. The inventive process is characterized in that: a) the intermixing of the homogeneous solution consisting of aldehyde, ketone and aqueous alkali lye occurs at a temperature ranging from 10 to 120 °C; b) the undissolved water and alkali hydroxide contained in the reaction mixture are subsequently separated out; c) while avoiding back mixing, the homogeneous reaction mixture is then guided through a reactor, which permits a residence time ranging from 2 to 300 minutes, at a temperature that is 10 to 120 °C higher than the boiling point of the lowest-boiling component and under a vapor pressure p ranging from 106 to 107 Pa; d) the reaction mixture is cooled by expansion; e) ketone is removed from the reaction mixture using vapor flowing in the opposite direction and; f) the raw product is dried and rid from excessive aldehyde and secondary components via a rectification column.
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Page/Page column 10
(2008/06/13)
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- Photochemical transformations of terpenoids in the presence of cyclodextrins
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The effect of complexation of terpene compounds with cyclodextrins on photolysis depends on the type of cyclodextrin and on the structure of the initial substrates. In some cases, only a change in the reaction rate is observed; in other cases, the complexation results in allylic rearrangements, hydride and acyl shifts, and cyclization with the formation of four-, five-, and six-membered cycles, whereas only cis-trans isomerization reactions are observed in the absence of complexation.
- Luzina,Tatarova,Korchagina,Salakhutdinov,Barkhash
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p. 183 - 193
(2007/10/03)
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