23733-68-8Relevant academic research and scientific papers
Advantageous heterogeneously catalysed hydrogenation of carvone with supercritical carbon dioxide
Melo, Catarina I.,Bogel-Lukasik, Rafal,Da Silva, Marco Gomes,Bogel-Lukasik, Ewa
, p. 2825 - 2830 (2011)
The hydrogenation of carvone was investigated for the first time in high-density carbon dioxide. The hydrogenation over 0.5 wt% Pd, or Rh, or Ru supported on alumina was found to be generally faster in a single supercritical (sc) phase (fluid reagents) than in a biphasic system (liquid + fluid reactants). The reaction with Pd produced fully hydrogenated products (isomers of carvomenthone) and carvacrol. The Rh catalyst was more selective and favoured carvomenthone isomers with higher selectivity and carvotanacetone as a secondary product. Additionally, the rhodium catalysed reaction exhibited high > 84% selectivity of carvotanacetone with the conversion of > 25% after only 2 min of reaction. The less active Ru catalyst gave significantly lower conversion and the product variety was greater as carvomenthone isomers, carvotanacetone and carvacrol were formed. The conversion and selectivity to carvomenthone within 2 h of the reaction starting followed the order: Pd > Rh > Ru and Rh > Pd > Ru, respectively. High conversion, and diverse and high selectivity accompanied by significant reduction in reaction time depending on the catalyst were achieved in supercritical CO2 compared with hydrogenation occurring in conventional organic solvents.
Unknown Camphor: Regioselective Rearrangement under Acylation in a CF3SO3H/(CF3CO)2O System
Kovalev, Vladimir,Shokova, Elvira,Chertkov, Vyacheslav,Tafeenko, Victor
, p. 1508 - 1512 (2016)
The utility of camphor in the chemical sciences is vast and well documented, yet the creation of camphor-derived potentially useful bicyclo[2.2.1]heptane scaffolds still remains one of the great challenges of synthetic organic chemistry. Herein, we show that CF3SO3H/(CF3CO)2O-mediated acylation of camphor with benzoic acids is accompanied by a cascade of alkyl and hydride shifts and opens access to a new type of polyfunctional isoborneol. In case of salicylic acids, camphor feels the presence of the ortho-hydroxy group in the aryl moiety, the influence of which provokes cleavage of the bicycloheptane skeleton to lead to monocyclic carvenone. The trifluoromethanesulfonic acid (TfOH)/trifluoroacetic anhydride (TFAA) mediated acylation of camphor with benzoic acids gives rise to a cascade of regioselective rearrangements of the bicycloheptane skeleton and allows the synthesis of a new type of previously unknown isoborneol. If salicylic acids are used as the acylating agents, the camphor is isomerized to give carvenone.
Method for synthesizing carvacrol from dipentene dioxide
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Paragraph 0017; 0019; 0020; 0021; 0022, (2019/01/24)
The invention discloses a method for synthesizing carvacrol from dipentene dioxide. The method comprises the following steps: step 1, utilizing the dipentene dioxide as a raw material and reducing thedipentene dioxide in a solvent A through a sodium borohydride water solution to obtain alpha,alpha,6-trimethyl-7-oxa bicyclo(4.1.0)heptane-3-methyl alcohol and 1,3,3-trimethyl-2-oxa bicyclo(2.2.2)octane-6-alcohol; step 2, dehydrating and rearranging the alpha,alpha,6-trimethyl-7-oxa bicyclo(4.1.0)heptane-3-methyl alcohol and 1,3,3-trimethyl-2-oxa bicyclo(2.2.2)octane-6-alcohol which are obtainedin step 1 through acid catalysis to obtain iso-dihydrocarvone; step 3, dissolving the iso-dihydrocarvone obtained in step 2 and a carbon-based compound catalyst into a solvent and heating the mixtureto generate dehydrogenation oxidation reaction, generating carvacrol, filtering the carvocrol to separate the carbon-based compound catalyst and performing reduced pressure rectification on filtrate to obtain a carvacrol finished product. The acid, the carbon-based compound catalyst and the solvent in the method disclosed by the invention all can be recycled, so that cost is reduced; the raw material of the dipentene dioxide in the method disclosed by the invention is an auxiliary product of the company, so that regeneration and comprehensive utilization of byproducts are achieved, and economic value of the byproducts is improved.
Heteropoly acid catalysis for the isomerization of biomass-derived limonene oxide and kinetic separation of the trans-isomer in green solvents
Cotta, Rafaela F.,Martins, Rafael A.,Pereira, Matheus M.,da Silva Rocha, Kelly A.,Kozhevnikova, Elena F.,Kozhevnikov, Ivan V.,Gusevskaya, Elena V.
, (2019/08/02)
Terpenes are an abundant class of natural products, which is important for flavor and fragrance industry. Many acid catalyzed reactions used for upgrading terpenes still involve mineral acids as homogeneous catalysts and/or toxic solvents. Heteropoly acids represent a well-established eco-friendly alternative to conventional acid catalysts. As these reactions are usually performed in the liquid phase, solvents play a critical role for the process sustainability. In the present work, we developed a catalytic route to valuable fragrance ingredients, dihydrocarvone and carvenone, from limonene oxide by its isomerization using silica-supported tungstophosphoric acid as a heterogeneous catalyst and dialkylcarbonates as green solvents. The reaction pathway can be switched between dihydrocarvone and carvenone (obtained in 90% yield each) simply by changing the reaction temperature. In addition, we developed an efficient method for kinetic separation of trans-limonene oxide from commercial cis/trans-limonene oxide mixture and stereoselective synthesis of trans-dihydrocarvone.
Enantioselective Synthesis of the Platensimycin Core by Silver(I)-Promoted Cyclization of Δ6-α-Iodoketone
Trajkovic, Milos,Ferjancic, Zorana,Saicic, Radomir N.,Bihelovic, Filip
, p. 4340 - 4344 (2019/02/28)
A chiral-pool-based synthesis of the platensimycin core was achieved using (S)-lactic acid as an inexpensive starting material. The cyclohexenone ring was closed in a Mukaiyama–Michael domino sequence, while the quaternary stereocenter was created by a highly stereoselective decarboxylative allylation. The spirobicyclic skeleton was constructed by a RCM reaction. A new silver(I)-promoted cyclization reaction of Δ6- and Δ7-α-iodoketones was developed and applied for the pivotal carbon–carbon bond formation. The scope and limitations of this methodology are also presented.
Method for synthesizing carvacrol from dipentene dioxide
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Paragraph 0014; 0016; 0017; 0018, (2019/01/24)
The invention discloses a method for synthesizing carvacrol from dipentene dioxide. The method comprises the following steps: step 1, utilizing the dipentene dioxide as a raw material and performing reducing reaction in a solvent A through the action of ammonium formate to obtain alpha,alpha,6-trimethyl-7-oxa bicyclo(4.1.0)heptane-3-methyl alcohol under the situations of hydrogen pressurization and utilizing Pd/C as a catalyst; step 2, performing dehydrating and rearranging reaction on the alpha,alpha,6-trimethyl-7-oxa bicyclo(4.1.0)heptane-3-methyl alcohol obtained in step 1 under acid catalysis to obtain iso-dihydrocarvone; step 3, dissolving the iso-dihydrocarvone obtained in step 2 and a carbon-based compound catalyst into a solvent and heating the mixture to generate dehydrogenation oxidation reaction, generating carvacrol, filtering the carvacrol to separate the carbon-based compound catalyst and performing reduced pressure rectification on filtrate to obtain a carvacrol finishedproduct. The Pd/C, the acid, the carbon-based compound catalyst and the solvent in the method disclosed by the invention can all be recycled, so that cost is reduced; the raw material of the dipentene dioxide in the method disclosed by the invention is an auxiliary product of the company, so that regeneration and comprehensive utilization of byproducts are achieved, and economic value of the byproducts is improved.
Method for synthetizing carvacrol through enediol
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Paragraph 0006; 0010, (2016/11/24)
The invention discloses a method for synthetizing carvacrol through enediol. The method comprises the following steps of (1) dissolving the enediol and a catalyst A into a solvent, heating to enable the enediol to produce dehydration, ring-opening and rearrangement reactions, generating iso-dihydrocarvone, after reaction, neutralizing pH to be 7 to 8 through aqueous alkali, standing for layering, and carrying out organic phase vacuum distillation to obtain an iso-dihydrocarvone finished product; (2) dissolving the iso-dihydrocarvone prepared through the step (1) and a catalyst B into a solvent, heating to produce dehydrogenation oxidation reaction, generating the carvacrol, filtering and separating the catalyst B, carrying out filter liquor vacuum distillation to obtain a carvacrol finished product. According to the method for synthetizing the carvacrol through the enediol provided by the invention, the raw materials are convenient in source, low in price and easy to obtain; the synthetic process is green and environmentally friendly; post-processing purification only depends on rectification, so that the process is simple; the catalysts can be recycled so as to be suitable for industrial production.
Method for synthesizing carvacrol by limo nene epoxides
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Paragraph 0014, (2016/11/14)
The invention provides a method for synthesizing carvacrol by limo nene epoxides. The method comprises the following steps: step 1, under the action of a Lewis acid catalyst A, limo nene epoxide is heated up for open-loop rearrangement reaction to produce isodihydrocarvone, after reaction, white oil is added into the reaction liquid, vacuum distillation is conducted to obtain an isodihydrocarvone end product, and the catalyst A remains in the residue; step 2, isodihydrocarvone prepared in the step 1 and a catalyst B are dissolved in a solvent, the solvent is heated up for dehydrogenation oxidation to produce carvacrol, the reaction process is monitored by gas chromatography, when the content of isodihydrocarvone is 30-40%, the reaction is terminated, the catalyst B is filtered and separated out, vacuum distillation is performed on the filtrate, isodihydrocarvone and the solvent which are not subjected to reaction are reclaimed, and distillation is further conducted to obtain a carvacrol end product. The raw material is low in price and easily accessible, the synthesis process is environment-friendly, the catalysts can be recycled, and the method provided by the invention is suitable for industrial production.
Carbon monoxide as a building block in organic synthesis. Part V. Involvement of palladium-hydride species in carbonylation reactions of monoterpenes. X-ray crystal structure of 4
Naigre, Ruth,Chenal, Thomas,Cipres, Isabelle,Kalck, Philippe,Daran, Jean-Claude,Vaissermann, Jacqueline
, p. 91 - 102 (2007/10/02)
A palladium precursor and SnCl2 as cocatalyst were used under 4 MPa of carbon monoxide for the catalytic alkoxycarbonylation of several monoterpenes into C11 esters.The active catalyst involves a palladium-hydride species whose formation was investigated.In the case of the model substrate 3-phenylpropene, the source of the hydrido ligand was determined to be the alkene itself.Allylic hydrogen abstraction seems to be a general way to produce the active hydridopalladium species since monoterpenes having labile allylic hydrogens were converted under exceptional mild conditions.An X-ray crystal structure analysis was carried out on . Key words: Palladium; X-ray structure; Terpenes; Carbonylation; Hydroesterification
Reactions of Some Cyclic Ethers in Superacids
Baig, Mirza Azam,Banthorpe, Derek V.,Carr, Graham,Whittaker, David
, p. 1981 - 1986 (2007/10/02)
The reactions of some epoxides and tetrahydrofuran derivatives in superacidic media have been studied.The tetrahydrofurans decompose only at 0 deg C or above, yielding, in some cases, unsaturated carbocations which react to give carbocyclic products, though many yield only tar.Cyclohexene oxides decompose more readily; unsubstituted, they slowly form an allylic ion; with one carbon at the epoxide link substituted they yield the ketone, and with both carbons substituted they give the ring-contracted aldehyde.Limonene 1,2-oxide behaves in a similar manner, though yielding small amounts of the ring-contracted protonated aldehyde (10).Reaction of geraniol 2,3-oxide is initially similar but the intermediate is intercepted intramolecularly to yield the hydroxy-iridoid ethers, 3,3,6β-trimethyl-cis-perhydrocyclopentafuran and 3,3,6α-trimethyl-cis-perhydrocyclopentafuran.Protonation of cyclohexene oxide or norbornene oxide yields onium salts, stable at -70 deg C, which show the addition to be either unsymmetrical (i.e. edge protonation) or to take place in two different positions.
