- Fungi-mediated biotransformation of the isomeric forms of the apocarotenoids ionone, damascone and theaspirane
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In this work, we describe a study on the biotransformation of seven natural occurring apocarotenoids by means of eleven selected fungal species. The substrates, namely ionone (α-, β- and γ-isomers), 3,4-dehydroionone, damascone (α- and β-isomers) and theaspirane are relevant flavour and fragrances components. We found that most of the investigated biotransformation reactions afforded oxidized products such as hydroxy- keto- or epoxy-derivatives. On the contrary, the reduction of the keto groups or the reduction of the double bond functional groups were observed only for few substrates, where the reduced products are however formed in minor amount. When starting apocarotenoids are isomers of the same chemical compound (e.g., ionone isomers) their biotransformation can give products very different from each other, depending both on the starting substrate and on the fungal species used. Since the majority of the starting apocarotenoids are often available in natural form and the described products are natural compounds, identified in flavours or fragrances, our biotransformation procedures can be regarded as prospective processes for the preparation of high value olfactory active compounds.
- Serra, Stefano,De Simeis, Davide
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- Synthesis and olfactory evaluation of the enantiomerically enriched forms of 7,11-epoxymegastigma-5(6)-en-9-one and 7,11-epoxymegastigma-5(6)-en-9-ols isomers, identified in Passiflora edulis
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A study on the synthesis of the isomers of the natural C-13 norterpenoids derivatives 7,11-epoxymegastigma-5(6)-en-9-one and 7,11-epoxymegastigma-5(6)-en- 9-ols is reported. The latter compounds were prepared from readily available racemic α-ionone and then resolved by mean of lipase-mediated acetylation. The obtained enantiomerically forms were evaluated for their odour properties.
- Brenna, Elisabetta,Fuganti, Claudio,Serra, Stefano
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p. 1699 - 1704
(2007/10/03)
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- Enzyme-mediated synthesis of (R)- and (S)-α-ionone
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Diastereoisomeric enrichment through fractional crystallisation of 4-nitrobenzoate derivatives of α-ionol, and enantioselective enzyme-mediated reactions of α-ionol and α-ionol acetate, were usefully combined to optimise two different procedures to enantiopure (S)- and (R)-ionone.
- Brenna, Elisabetta,Fuganti, Claudio,Grasselli, Piero,Redaelli, Mara,Serra, Stefano
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p. 4129 - 4134
(2007/10/03)
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- Iodine as an Acetyl Transfer Catalyst
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Iodine catalyses the acetylation of amines, phenols and alcohols, including tertiary ones, with acetic anhydride in excellent yield.
- Borah, Ruli,Deka, Nabajyoti,Sarma, Jadab C.
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p. 110 - 111
(2007/10/03)
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- Allylsilanes derived from α- and β-ionone. Synthesis and unusual reactivity with electrophiles
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Silylcupration of α- and β-ionol acetates selectively gave the corresponding allylsilanes with direct substitution of the acetate with a trimethylsilyl group. Reactions of these products with electrophiles showed the unusual absence of the allylic shift, typical in nucleophilic condensations of allylsilanes. Ionotrimethylsilanes are effective building blocks for synthesis of terpenes and carotenoids.
- Azzari,Faggi,Gelsomini,Taddei
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p. 6067 - 6070
(2007/10/02)
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