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Elena V Gusevskaya - One of the best experts on this subject based on the ideXlab platform.
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selective hydrogenation of Myrcene catalyzed by sol gel pd sio2
Applied Catalysis A-general, 2005Co-Authors: Patricia A Roblesdutenhefner, Marcelo Gomes Speziali, Edesia Martins Barros De Sousa, Eduardo Dos N Santos, Elena V GusevskayaAbstract:Abstract Sol–gel palladium silica composites are active catalysts for the selective hydrogenation of Myrcene. The temperature of the thermal treatment of the catalyst is essential for its selectivity. Catalysts treated at 1100 °C give monohydrogenated products with excellent combined selectivity of 90–95% at almost complete conversion of the substrate. The obtained products arise from the σ-alkyl and/or η 3 -allyl intermediates formed by the interaction of the palladium catalyst with both terminal C C bonds of Myrcene and the main products (ca. 70%) result from the reaction with the less substituted one. The selective monohydrogenation of Myrcene could be useful to produce a mixture of diolefins of different reactivity, which could be further transformed to oxygenated derivatives with selectivities better than Myrcene itself.
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Selective hydrogenation of Myrcene catalyzed by sol–gel Pd/SiO2
Applied Catalysis A-general, 2005Co-Authors: Patricia A. Robles-dutenhefner, Marcelo Gomes Speziali, Edesia Martins Barros De Sousa, Eduardo N. Dos Santos, Elena V GusevskayaAbstract:Abstract Sol–gel palladium silica composites are active catalysts for the selective hydrogenation of Myrcene. The temperature of the thermal treatment of the catalyst is essential for its selectivity. Catalysts treated at 1100 °C give monohydrogenated products with excellent combined selectivity of 90–95% at almost complete conversion of the substrate. The obtained products arise from the σ-alkyl and/or η 3 -allyl intermediates formed by the interaction of the palladium catalyst with both terminal C C bonds of Myrcene and the main products (ca. 70%) result from the reaction with the less substituted one. The selective monohydrogenation of Myrcene could be useful to produce a mixture of diolefins of different reactivity, which could be further transformed to oxygenated derivatives with selectivities better than Myrcene itself.
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selective hydrogenation of Myrcene catalyzed by complexes of ruthenium chromium iridium and rhodium
Journal of Molecular Catalysis A-chemical, 2005Co-Authors: Marcelo Gomes Speziali, Patricia A Roblesdutenhefner, Elena V Gusevskaya, Flavia C C Moura, Maria Helena Araujo, Eduardo Dos N SantosAbstract:Abstract The hydrogenation of Myrcene catalyzed by Ru, Cr, Ir and Rh complexes leads to the formation of a complex mixture of mono-, di- and trihydrogenated products. Seven major products have been characterized, showing that they arise from the σ-alkyl and/or η 3 -allyl intermediates formed by the reaction of metal catalysts with both terminal C C bonds of Myrcene. A good control of chemoselectivity has been achieved through the appropriate choice of the metal and reaction conditions. Monohydrogenated products have been obtained with excellent combined selectivity of 95–98% at a high conversion of Myrcene (>80%). Among the catalysts studied, rhodium complexes show the highest activity and selectivity, especially at temperatures lower than 100 °C.
Jorg Bohlmann - One of the best experts on this subject based on the ideXlab platform.
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e β ocimene and Myrcene synthase genes of floral scent biosynthesis in snapdragon function and expression of three terpene synthase genes of a new terpene synthase subfamily
The Plant Cell, 2003Co-Authors: Natalia Dudareva, Diane M Martin, Christine M Kish, Natalia Kolosova, Nina M Gorenstein, Jenny Faldt, Barbara Miller, Jorg BohlmannAbstract:Snapdragon flowers emit two monoterpene olefins, Myrcene and (E)-β-ocimene, derived from geranyl diphosphate, in ad-dition to a major phenylpropanoid floral scent component, methylbenzoate. Emission of these monoterpenes is regulated developmentally and follows diurnal rhythms controlled by a circadian clock. Using a functional genomics approach, we have isolated and characterized three closely related cDNAs from a snapdragon petal-specific library that encode two Myrcene synthases (ama1e20 and ama0c15) and an (E)-β-ocimene synthase (ama0a23). Although the two Myrcene synthases are almost identical (98%), except for the N-terminal 13 amino acids, and are catalytically active, yielding a single monoterpene product, Myrcene, only ama0c15 is expressed at a high level in flowers and contributes to floral Myrcene emission. (E)-β-Ocimene synthase is highly similar to snapdragon Myrcene synthases (92% amino acid identity) and produces predominantly (E)-β-ocimene (97% of total monoterpene olefin product) with small amounts of (Z)-β-ocimene and Myrcene. These newly isolated snapdragon monoterpene synthases, together with Arabidopsis AtTPS14 (At1g61680), define a new subfamily of the terpene synthase (TPS) family designated the Tps-g group. Members of this new Tps-g group lack the RRx8W motif, which is a characteristic feature of the Tps-d and Tps-b monoterpene synthases, suggesting that the reaction mechanism of Tps-g monoterpene synthase product formation does not proceed via an RR-dependent isomerization of geranyl diphosphate to 3S-linalyl diphosphate, as shown previously for limonene cyclase. Analyses of tissue-specific, developmental, and rhythmic expression of these monoterpene synthase genes in snapdragon flowers revealed coordinated regulation of phenylpropanoid and isoprenoid scent production.
Pedro M Santos - One of the best experts on this subject based on the ideXlab platform.
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deciphering the genome repertoire of pseudomonas sp m1 toward β Myrcene biotransformation
Genome Biology and Evolution, 2015Co-Authors: Pedro Soarescastro, Pedro M SantosAbstract:Pseudomonas sp. M1 is able to mineralize several unusual substrates of natural and xenobiotic origin, contributing to its competence to thrive in different ecological niches. In this work, the genome of M1 strain was resequenced by Illumina MiSeq to refine the quality of a published draft by resolving the majority of repeat-rich regions. In silico genome analysis led to the prediction of metabolic pathways involved in biotransformation of several unusual substrates (e.g., plant-derived volatiles), providing clues on the genomic complement required for such biodegrading/biotransformation functionalities. Pseudomonas sp. M1 exhibits a particular sensory and biotransformation/biocatalysis potential toward β-Myrcene, a terpene vastly used in industries worldwide. Therefore, the genomic responsiveness of M1 strain toward β-Myrcene was investigated, using an RNA sequencing approach. M1 cells challenged with β-Myrcene(compared with cells grown in lactate) undergo an extensive alteration of the transcriptome expression profile, including 1,873 genes evidencing at least 1.5-fold of altered expression (627 upregulated and 1,246 downregulated), toward β-Myrcene-imposed molecular adaptation and cellular specialization. A thorough data analysis identified a novel 28-kb genomic island, whose expression was strongly stimulated in β-Myrcene-supplemented medium, that is essential for β-Myrcene catabolism. This island includes β-Myrcene-induced genes whose products are putatively involved in 1) substrate sensing, 2) gene expression regulation, and 3) β-Myrcene oxidation and bioconversion of β-Myrcene derivatives into central metabolism intermediates. In general, this locus does not show high homology with sequences available in databases and seems to have evolved through the assembly of several functional blocks acquired from different bacteria, probably, at different evolutionary stages.
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adaptation to β Myrcene catabolism in pseudomonas sp m1 an expression proteomics analysis
Proteomics, 2009Co-Authors: Pedro M Santos, Isabel SacorreiaAbstract:: Beta-Myrcene, a monoterpene widely used as a fragrance and flavoring additive, also possesses analgesic, anti-mutagenic, and tyrosinase inhibitory properties. In order to get insights into the molecular mechanisms underlying the ability of Pseudomonas sp. M1 to catabolize beta-Myrcene, an expression proteomics approach was used in this study. Results indicate that the catabolic enzyme machinery for beta-Myrcene utilization (MyrB, MyrC, and MyrD and other uncharacterized proteins) is strongly induced when beta-Myrcene is present in the growth medium. Since an M1 mutant, lacking a functional 2-methylisocitrate dehydratase, is not able to grow in mineral medium with beta-Myrcene or propionic acid as the sole C-source, and also based on the expression proteomic analysis carried out in this study, it is suggested that the beta-Myrcene catabolic intermediate propionyl-CoA is channeled into the central metabolism via the 2-methylcitrate cycle. Results also suggest that the major alteration occurring in the central carbon metabolism of cells growing in beta-Myrcene-containing media is related with the redistribution of the metabolic fluxes leading to increased oxaloacetate production. Other up-regulated proteins are believed to prevent protein misfolding and aggregation or to play important structural roles, contributing to the adaptive alteration of cell wall and membrane organization and integrity, which are essential features to allow the bacterium to cope with the highly lipophilic beta-Myrcene as C-source.
Marcelo Gomes Speziali - One of the best experts on this subject based on the ideXlab platform.
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selective hydrogenation of Myrcene catalyzed by sol gel pd sio2
Applied Catalysis A-general, 2005Co-Authors: Patricia A Roblesdutenhefner, Marcelo Gomes Speziali, Edesia Martins Barros De Sousa, Eduardo Dos N Santos, Elena V GusevskayaAbstract:Abstract Sol–gel palladium silica composites are active catalysts for the selective hydrogenation of Myrcene. The temperature of the thermal treatment of the catalyst is essential for its selectivity. Catalysts treated at 1100 °C give monohydrogenated products with excellent combined selectivity of 90–95% at almost complete conversion of the substrate. The obtained products arise from the σ-alkyl and/or η 3 -allyl intermediates formed by the interaction of the palladium catalyst with both terminal C C bonds of Myrcene and the main products (ca. 70%) result from the reaction with the less substituted one. The selective monohydrogenation of Myrcene could be useful to produce a mixture of diolefins of different reactivity, which could be further transformed to oxygenated derivatives with selectivities better than Myrcene itself.
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Selective hydrogenation of Myrcene catalyzed by sol–gel Pd/SiO2
Applied Catalysis A-general, 2005Co-Authors: Patricia A. Robles-dutenhefner, Marcelo Gomes Speziali, Edesia Martins Barros De Sousa, Eduardo N. Dos Santos, Elena V GusevskayaAbstract:Abstract Sol–gel palladium silica composites are active catalysts for the selective hydrogenation of Myrcene. The temperature of the thermal treatment of the catalyst is essential for its selectivity. Catalysts treated at 1100 °C give monohydrogenated products with excellent combined selectivity of 90–95% at almost complete conversion of the substrate. The obtained products arise from the σ-alkyl and/or η 3 -allyl intermediates formed by the interaction of the palladium catalyst with both terminal C C bonds of Myrcene and the main products (ca. 70%) result from the reaction with the less substituted one. The selective monohydrogenation of Myrcene could be useful to produce a mixture of diolefins of different reactivity, which could be further transformed to oxygenated derivatives with selectivities better than Myrcene itself.
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selective hydrogenation of Myrcene catalyzed by complexes of ruthenium chromium iridium and rhodium
Journal of Molecular Catalysis A-chemical, 2005Co-Authors: Marcelo Gomes Speziali, Patricia A Roblesdutenhefner, Elena V Gusevskaya, Flavia C C Moura, Maria Helena Araujo, Eduardo Dos N SantosAbstract:Abstract The hydrogenation of Myrcene catalyzed by Ru, Cr, Ir and Rh complexes leads to the formation of a complex mixture of mono-, di- and trihydrogenated products. Seven major products have been characterized, showing that they arise from the σ-alkyl and/or η 3 -allyl intermediates formed by the reaction of metal catalysts with both terminal C C bonds of Myrcene. A good control of chemoselectivity has been achieved through the appropriate choice of the metal and reaction conditions. Monohydrogenated products have been obtained with excellent combined selectivity of 95–98% at a high conversion of Myrcene (>80%). Among the catalysts studied, rhodium complexes show the highest activity and selectivity, especially at temperatures lower than 100 °C.
Nunes M Da Ponte - One of the best experts on this subject based on the ideXlab platform.
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vapour liquid equilibrium for β Myrcene and carbon dioxide and or hydrogen and the volume expansion of β Myrcene or limonene in co2 at 323 15 k
Fluid Phase Equilibria, 2009Co-Authors: Ewa Bogelłukasik, A Szudarska, Rafal Bogelłukasik, Nunes M Da PonteAbstract:Abstract Vapour–liquid equilibrium measurements for binary and ternary (carbon dioxide + β-Myrcene and carbon dioxide + β-Myrcene + hydrogen) systems have been carried out at 323.15 K and pressures in the range from 7 MPa to the critical pressure of the binary mixture and at pressures from 10 to 14 MPa for the investigated ternary systems. Samples from the coexisting phases were taken, and compositions were determined experimentally. Results were correlated using the Peng–Robinson and the Soave–Redlich–Kwong equations of state with the Mathias–Klotz–Prausnitz mixing rule. The set of interaction parameters for the employed equations of state and applied mixing rule for the system of CO2 + β-Myrcene and of CO2 + β-Myrcene + H2 were obtained. Additionally, the volume expansion of the liquid phase for the binary mixtures (carbon dioxide + β-Myrcene and carbon dioxide + limonene) were measured at 323.15 K and at pressures from 4 MPa up to very close to the critical pressure of the mixture. The ratio of liquid phase total volumes at the given pressure and at 4 MPa was calculated.
