cas 499-75-2, Carvacrol | Articles data

Articles about 499-75-2Total 63 be found

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Wolinsky,J.,Hutchins,R.O.
p. 3294 - 3299
(1972)
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A Comparison of Reaction Kinetics Observed under Microwave Irradiation and Conventional Heating
Kinetic studies were made of two reactions under microwave heating and under conventional heating.The reactions were the acid-catalyzed isomerization of carvone to carvacrol and the Diels-Alder reaction between anthracene and diethyl maleate.It was found that the rates of these reactions were the same, within experimental error, under either mode of heating at the same temperature.The activation parameters for the isomerization were measured as E(excit) = 89 +/- 3 kJ/mol, ln A = 21.5 +/- 0.8 (oil bath); and E(excit) = 83 +/- 5 kJ/mol, ln A = 19.7 +/- 1.6 (microwave).The activation parameters for the Diels-Alder reaction were E(excit) = 94 +/- 10 kJ/mol, ln A = 15.6 +/- 2.3 (oil bath); and E(excit) = 88 +/- 8 kJ/mol, ln A = 13.9 +/- 2.0 (microwave).
Raner, Kevin D.,Strauss, Christopher R.,Vyskoc, Ferdinand,Mokbel, Luci
p. 950 - 953
(1993)
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The chemistry of thujone. XIX. 1 Acid-promoted ring cleavage of thujone-derived cyclopropylcarbinols
Thujone-derived cyclopropylcarbinols can cleave via three distinct pathways: the exo cleavage, the endo cleavage, and the interesting cyclopropylcarbinyl rearrangement. Factors determining which pathway is adopted under specific conditions are discussed. A short sequence leading to synthesis of the sesquiterpene (+)-β-cyperone is described.
Kutney, James P.,Chen, Yong-Huang,Rettig, Steven J.
p. 1753 - 1761
(1996)
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Chlorination and Base-Induced Dehydrochlorination of (-)-3-Isothujone
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Zoller, Uri
p. 4481 - 4483
(1993)
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Method for efficiently preparing carvacrol from o-cresol
The invention discloses a method for efficiently preparing carvacrol from o-cresol, which comprises the following steps: a, carrying out alkylation reaction by using o-cresol and isopropanol as raw materials and diatomite phosphoric acid as a catalyst; b, preparation of a diatomite phosphoric acid catalyst: firstly drying the diatomite carrier at 100 DEG C; c, adopting phosphoric acid as a dipping solution and diatomite as a solid adsorbent, and dipping for 3-48 hours; and d, after the impregnation is finished, calcining the obtained diatomite at the calcining temperature. According to the method for efficiently preparing the carvacrol from the o-cresol, the content of the carvacrol is 97-99.5%, the yield is 75-85%, and the process is low in production cost, high in conversion rate, high in yield and convenient to industrialize.
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Paragraph 0022-0101

(2021/06/09)

3'-KETOGLYCOSIDE COMPOUND FOR THE SLOW RELEASE OF A VOLATILE ALCOHOL
The present invention relates to a 3'-ketoglycoside compound defined by formula (I) and its use for controlled release of alcohols, in particular alcohols showing an insect repellent effect. It relates also to a process for preparing the 3'-ketoglycoside compound of formula (I). It further relates to a composition comprising a 3'- ketoglycoside compound of formula (I). It relates also to the use of a 3'-ketoglycoside compound of formula (I) for the controlled release of alcohols. It related also to a method of use of such composition.
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Page/Page column 61-62

(2021/08/20)

Method for synthesizing carvacrol from 8-hydroxycarvone
The invention discloses a method for synthesizing carvacrol from 8-hydroxy carvone, which comprises the following steps: dissolving the raw material 8-hydroxy carvone and a catalyst in a solvent, heating to perform dehydration and rearrangement reaction on the 8-hydroxy carvone to generate carvacrol, performing filtering to separate the catalyst after the reaction is finished, rectifying the filtrate under reduced pressure, and recycling the solvent; and further decompressing and rectifying to obtain a carvacrol finished product. The catalyst is a strong acid or weak acid cationic resin catalyst. According to the brand-new carvacrol synthesis method provided by the invention, the existing 8-hydroxy carvone is comprehensively utilized, the application range of the 8-hydroxy carvone is expanded, and the production cost of carvacrol is reduced; the method is mild in reaction condition, easy and convenient to operate and high in reaction efficiency, the product yield can reach 98%, and themethod has good industrial application prospects.
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Paragraph 0005; 0015-0026

(2021/03/13)

Method for preparing carvacrol by using limonene epoxide as hydrogenation acceptor
The invention discloses a method for preparing carvacrol by using limonene epoxide as a hydrogenation acceptor, and belongs to the field of fine chemical engineering. According to the method, carvacrol is synthesized by taking carvacrol as a raw material, and limonene epoxide is added as a hydrogenation acceptor. The method has the advantages that limonene epoxide can timely consume active hydrogen generated by reaction, generation of hydrogen is avoided, the reaction is carried out under normal pressure, the safety of the reaction is improved, and forward movement of dehydrogenation reaction is promoted, so that the product yield is improved; the reaction time is short and the process is simple; and the supported palladium-carbon catalyst can be repeatedly used, so that green industrial production is realized.
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Paragraph 0013; 0016-0023

(2021/07/31)

Novel palladium nanoparticles supported on mesoporous natural phosphate: Catalytic ability for the preparation of aromatic hydrocarbons from natural terpenes
Various ratios of palladium nanoparticles supported on mesoporous natural phosphate (Pd@NP) were prepared using the wetness impregnation method. The prepared catalysts were characterized by IR, XRD, CV, SEM, EDX, XRF, TEM and BET analysis. The reduction and preparation of the palladium nanoparticles afford a crystallite size of 10.88 nm. The performance of the synthesized catalyst was investigated in the solvent-free dehydroaromatization of α-, β- and γ-himachalene mixture from Cedrus atlantica oil as a model substrate. In order to achieve an efficient and selective catalysis, the catalytic dehydroaromatization of various terpenes such as limonene, limonaketone, carvone, carveol and perillyl alcohol was studied. The Pd@NP catalyst performed a high catalytic activity, selectivity and recyclability in the terpenes dehydroaromatization reaction.
Mekkaoui, Ayoub Abdelkader,Aberkouks, Abderrazak,Fkhar, Lahcen,Ait Ali, Mustapha,El Firdoussi, Larbi,El Houssame, Soufiane
(2020/07/24)

Synthesis of a pyrrolidine derivative of a carvotacetone and monoterpenes for anti-methicillin-resistant Staphylococcus aureus and anti-cryptococcal properties
Monoterpene derivatives are of great biological relevance in the pharmaceutical industry. In the present study, pyrrolidine derivative of a carvotacetone, 3-O-benzylcarvotacetone (1), and selected monoterpenes (3-hydroxy-2-isopropyl-5-methyl-p-benzoquinone (3) and cis-piperitol (5)) were prepared to provide (R)-1-(4-(benzyloxy)-5-isopropyl-2-methylcyclohexa-1,3-dien-1-yl)-pyrrolidine (2), 2-isopropyl-5-methyl-3,6-dioxocyclohexa-1,4-dien-1-yl acetate (4), cis-3-hydroxypiperitone (6) and carvacrol (7). Structure of 2 was determined based on NMR and HRMS spectral data. Compound 4 exhibited activity against fungi Cryptococcus neoformans with an IC50 value of 50 value of 14.97μg/mL against methicillin resistant Staphylococcus aureus bacteria. Previous to the current study, both compound 6 and 7 had been reported to have anti-microbial and anti-fungal activities.
Byamukama, Robert,Kamau, Rahab W.,Kumarihamy, Mallika,Masila, Veronica M.,Midiwo, Jacob O.,Muhammad, Ilias,Ndakala, Albert J.
(2020/10/27)

A antibacterial agent perfume Carvacrol chemical synthesis process
The invention relates to an antibacterial agent Carvacrol chemical synthesis process. The synthesizing process selects the O-methyl phenol and isopropanol as the raw material, in order to compound dichloromethane, hexane (petroleum ether) and the like as the reaction solvent, through alkylation reaction, liquid-liquid extraction, often, concentrated under reduced pressure, reduced pressure distillation make Carvacrol. The synthesizing process has simple technological process, the production cost is low, the extraction rate is high, the product quality is good and the like, easy to industrial production.
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Paragraph 0016-0019

(2019/07/04)

Method for synthesizing carvacrol from dipentene dioxide
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.
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Paragraph 0014; 0015; 0016; 0017; 0018

(2019/01/24)

Method for synthesizing carvacrol from dipentene dioxide
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.
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Paragraph 0017; 0018; 0019; 0020; 0021; 0022

(2019/01/24)

Demethylenation of Cyclopropanes via Photoinduced Guest-to-Host Electron Transfer in an M6L4 Cage
Unusual demethylenation reactions of cyclopropanes under UV-light irradiation were found within a cavity of a photoactive coordination cage. The reaction proceeded via a guest-to-host electron transfer owing to the highly electron-deficient nature of the cage. The reactions were highly chemoselective and enabled late-stage derivatization of a steroid molecule, which led to a totally new un-natural steroid.
Cullen, William,Takezawa, Hiroki,Fujita, Makoto
supporting information
p. 9171 - 9173
(2019/06/24)

Biomimetic Transformation of p-Menthene Glucosides into p-Cymenes and Carvotanacetone
A biomimetic transformation of p-menthene glucosides into aromatic monoterpenoids that alluded to mechanisms for essential oil metabolism, which lines up with the precepts of molecular economy, is described. Acid treatment of (-)-(3S,4S,6R)-3,6-dihydroxy-1-menthene 3-O-β-d-glucopyranoside (1) and (-)-(3S,4R,5R,6S)-3,5,6-trihydroxy-1-menthene 3-O-β-d-glucopyranoside (2), from Ageratina glabrata, yielded p-cymene (7) and carvacrol (9). The stable oxidized intermediates (+)-(3S,4S,6R)-3,6-dihydroxy-1-menthene (3), (+)-(1S,4S,6R)-1,6-dihydroxy-2-menthene (4), (+)-(1R,4S,6R)-1,6-dihydroxy-2-menthene (5), (+)-(4S,6R)-yabunikkeol (6), (+)-(4S)-carvotanacetone (8), (+)-(1S,4S,5R,6R)-1,5,6-trihydroxy-2-menthene (15), (+)-(1R,4S,5R,6R)-1,5,6-trihydroxy-2-menthene (16), and the new (+)-(4S,5R,6S)-1(7),2-menthadiene (17) permitted establishment of the reaction mechanisms. The reactivity of the hydroxy groups of 4 and 5, as well as those of 15 and 16, was compared by acetylation reactions and supported by DFT calculations, revealing diminished reactivity in 4 and 15 due to the cis configuration of their hydroxy groups at C-1 and C-6. In addition, p-cymene (7) was detected as one of the major constituents of the essential oil of A. glabrata, which matches well with the biomimetic study.
Pardo-Novoa, Julio C.,Arreaga-González, Héctor M.,Galván-Gómez, Sinuhé,Rodríguez-García, Gabriela,Del Río, Rosa E.,Cerda-García-Rojas, Carlos M.,Joseph-Nathan, Pedro,Gómez-Hurtado, Mario A.
p. 485 - 491
(2019/03/08)

Method of preparing 3-isopropyl-5-cresol and carvacrol with 3-carene
The invention discloses a method of preparing 3-isopropyl-5-cresol and carvacrol with 3-carene. The method comprises the following steps that 3-carene is reacted with oxygen at a room temperature to produce a product I under the catalysis of CrO3-Al2O3, wherein the product I is prepared from the main components including 5-carone, 2-carone and 4-carone with the selectivity ratio being about 10.8 to 3.5 to 1.0; the product I is distilled to recover 3-carene, wherein the recovery rate is larger than 80 percent, and the recovery purity is larger than 94 percent; the residual components are converted to a product II at 230 DEG C under catalysis of a 13X type molecular sieve, and reduced pressure distillation is performed on the product II to obtain a mixed phenol product with the purity largerthan 96 percent, wherein the product II is prepared from the main components including 3-isopropyl-5-cresol and carvacrol, the raw material conversion rate is 100 percent, the total selectivity of phenolic products can reach 98 percent, and the selectivity ratio of the two phenolic products is about 2.2 to 1.0; and column chromatography isolation is performed on the product II to obtain 3-isopropyl-5-cresol and carvacrol with the purities larger than 97 percent respectively.
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Paragraph 0064; 0065; 0066; 0067; 0068; 0069; 0070-0074

(2019/02/04)

Silica gel-mediated hydrohalogenation of unactivated alkenes using hydrohalogenic acids under organic solvent-free conditions
Silica gel-mediated hydrochlorination of unactivated alkenes using 35% hydrochloric acid under organic solvent-free conditions proceeded to give the corresponding chlorides in good yields. Hydrobromination or hydriodination using 47% hydrobromic acid or 55% hydriodic acid afforded the corresponding halides, respectively. Silica gel could be recycled five times without any significant loss of activities.
Tanemura, Kiyoshi
supporting information
p. 4293 - 4298
(2018/11/10)

Method for preparing hydrocarbyl phenol by catalytic conversion of phenolic compound in presence of molybdenum-based catalyst
The invention discloses a method for preparing hydrocarbyl phenol by catalytic conversion of a phenolic compound in the presence of a molybdenum-based catalyst. The method comprises mixing a phenoliccompound, a molybdenum-based catalyst and a reaction solvent, adding the mixture into a sealed reactor, feeding gas into the reactor, heating the mixture to 150-350 DEG C, carrying out stirring for areaction for 0.5-2h, then filtering to remove a solid catalyst and carrying out rotary evaporateion to obtain a liquid product. The phenolic compound has a wide source, a cost is low, product alkyl phenol selectivity is high, an added value is high, alcohol or an alcohol-water mixture is used as a reaction solvent, environmental friendliness is realized, pollution is avoided, any inorganic acids and alkalis are avoided in the reaction process, the common environmental pollution problems in the biomass processing technology are solved, the reaction conditions are mild, the process can be carried out at a low temperature, high-efficiency conversion of the reactants can be realized without consuming hydrogen gas and the method is suitable for large-scale industrial trial production.
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Paragraph 0046; 0070

(2018/04/02)

A Ni-Mg-Al layered triple hydroxide-supported Pd catalyst for heterogeneous acceptorless dehydrogenative aromatization
In the presence of a Ni-Mg-Al layered triple hydroxide-supported Pd catalyst, the acceptorless dehydrogenative aromatization of a wide range of cyclohexanols/cyclohexanones and cyclohexylamines efficiently proceeded to give the corresponding phenols and anilines, respectively, in moderate to high yields with the liberation of molecular hydrogen.
Jin, Xiongjie,Taniguchi, Kento,Yamaguchi, Kazuya,Nozaki, Kyoko,Mizuno, Noritaka
supporting information
p. 5267 - 5270
(2017/07/10)

Carvacrol synthetic method (by machine translation)
The present invention provides a method for synthesizing Carvacrol, comprising the following steps: step one, the catalyst under stirring montmorillonite into organic solvent mixed, the temperature rising to 130-160 °C carvone dropping when, in this condition, carvone isomerization, and the mass ratio of carvone states the montmorillonite clay 25-100 : 500-1000 ; the organic solvent and mass ratio of carvone 50-500 : 500-2000 ; step two, the reaction process is monitored through gas chromatography (GC), after the reaction, filtration, collection of solid catalyst, Carvacrol rectification product filtrate under reduced pressure. The traditional method compared with the strong acid such as sulfuric acid or the like, the invention has obvious advantages : (a) polynite consumption is small, the can be catalytic amount ; (b) after treatment is convenient, there is no need for the neutralization reaction, as long as the filtering to remove the montmorillonite can be obtained for rectification after the finished product ; (c) filtering after the reaction of the montmorillonite can be recycled, economy and environmental protection. Mild reaction conditions of the invention, the synthetic process of green, is extremely suitable for industrial production. (by machine translation)
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Paragraph 0015

(2016/11/14)

Method for synthetizing carvacrol through enediol
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.
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Paragraph 0006; 0016

(2016/11/24)

Method for synthesizing carvacrol by limo nene epoxides
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.
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Paragraph 0012

(2016/11/14)

Method for preparing carvacrol from L-carveol
The invention discloses a method for preparing carvacrol from L-carveol. Palladium on carbon and L-carveol are added to a container provided with a stirring device, the mixture is heated to 115-140 DEG C while being stirred, has a thermal insulation reaction for 1-3 hours (while air is blown in), cooled to the room temperature and filtered, filtrate is subjected to decompressing distillation, and carvacrol is prepared, wherein the mass ratio of the catalyst palladium on carbon to L-carveol is 1:(10-50). L-carveol is taken as a raw material, carvacrol is synthesized in a one-step method, the reaction time is short, the process is simple, the catalyst is easy to recover and can be repeatedly used, the yield of the product is high, no solvents are required, no sewage is produced, and the method is safe, environment-friendly and suitable for industrial production.
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Paragraph 0012

(2017/03/08)

Method for preparing carvacrol from 2-hydroxy-5-isopropenyl-2-methylcyclohexanone
The invention discloses a method for preparing carvacrol from 2-hydroxy-5-isopropenyl-2-methylcyclohexanone. The method uses 2-hydroxy-5-isopropenyl-2-methylcyclohexanone as a raw material and carries out intramolecular dehydration and intramolecular rearrangement in an organic solvent with phosphoric pentoxide as a dehydrating agent to prepare carvacrol. The method comprises the following concrete steps: (1) successively adding the organic solvent, phosphoric pentoxide and 2-hydroxy-5-isopropenyl-2-methylcyclohexanone into a reactor provided with a stirring device, carrying out stirring, then heating the obtained mixture to 98 to 108 DEG C, carrying out a reaction for 1 to 3 h with the temperature maintained, then cooling a reaction product to room temperature (in a range of 20 to 30 DEG C), washing the reaction product with water and then carrying out layering so as to separate a water layer; (2) extracting the water layer with ethyl acetate and combining organic phases; and (3) washing the combined organic phase with a saturated sodium bicarbonate solution and clear water in sequence, then drying the organic phase with anhydrous sodium sulfate and carrying out silica gel column chromatographic separation so as to obtain carvacrol. The method provided by the invention has the advantages of convenience in operation, mild reaction conditions, high yield, good product quality, etc.
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Paragraph 0008; 0013

(2016/10/20)

Production of nanocatalyst from natural magnetite by glow discharge plasma for enhanced catalytic ozonation of an oxazine dye in aqueous solution
Cheap natural magnetite (NM) was modified with oxygen plasma owing to its cleaning effect by chemical etching and with argon plasma due to its sputtering effect resulting in more surface roughness. These plasmas were utilized individually or in the order of first O2 and then Ar plasmas, respectively. The performance of the plasma treated magnetites (PTMs) was higher than NM for treatment of Basic Blue 3 (BB3) in catalytic ozonation (O3/PTM). The properties of NM and the most efficient treated magnetite (PTM4) samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Brunauer-Emmett-Teller (BET) and scanning electron microscopy (SEM) methods. The optimal values were chosen for operational parameters including ozone concentration (0.3 g/L), initial pH (6.7) and PTM4 dosage (600 mg/L). GC-Mass analysis was applied to detect intermediates. Environmentally-friendly treatment of the NM, simple separation of the catalyst, negligible leached iron concentration, successive reusability at milder pH and unaffected efficiency in the presence of inorganic salts are the main advantages of the PTM4.
Taseidifar, Mojtaba,Khataee, Alireza,Vahid, Behrouz,Khorram, Sirous,Joo, Sang Woo
p. 218 - 226
(2015/05/20)

Platinum(IV)-Catalyzed Synthesis of Unsymmetrical Polysubstituted Benzenes via Intramolecular Cycloaromatization Reaction
A one-pot synthesis of polysubstituted benzene derivatives was achieved via a platinum(IV)-catalyzed intramolecular cycloaromatization reaction. The reaction proceeds via a tandem skeletal rearrangment, dehydration and double bond isomerization, which proved to be very useful for the syntheses of a range of interesting polyalkyl-substituted benzenes.
Zheng, Shuyan,Zhang, Jinghua,Shen, Zhengwu
supporting information
p. 2803 - 2808
(2015/09/28)

Rapid Conventional and Microwave-Assisted Decarboxylation of L-Histidine and Other Amino Acids via Organocatalysis with R-Carvone under Superheated Conditions
This article reports a new methodology taking advantage of superheated chemistry via either microwave or conventional heating for the facile decarboxylation of alpha amino acids using the recoverable organocatalyst, R-carvone. The decarboxylation of amino acids is an important synthetic route to biologically active amines, and traditional methods of amino acid decarboxylation are time consuming (taking up to several days in the case of L-histidine), are narrow in scope, and make use of toxic catalysts. Decarboxylations of amino acids including L-histidine occur in just minutes while replacing toxic catalysts with green catalyst, spearmint oil. Yields are comparable to or exceed previous methods and purification of product ammonium chloride salts is aided by an isomerization reaction of residual catalyst to phenolic carvacrol. The method has been shown to be effective for the decarboxylations of a range of natural, synthetic, and protected amino acids.
Jackson, Douglas M.,Ashley, Robert L.,Brownfield, Callan B.,Morrison, Daniel R.,Morrison, Richard W.
p. 2691 - 2700
(2015/12/18)

A powerful tool for acid catalyzed organic addition and substitution reactions
A novel green chemistry tool for acid catalyzed reactions has been developed. The multipurpose tool is based on the ability of dry solid materials to donate protons (H+) to starting materials combined with the simultaneous use of a nucleophile (e.g. NaI). The methods enable the following reactions to be conducted at 20-50 °C: selective addition of iodine or alcohols to more substituted carbon in R2CCH2 systems (R ≠ H), esterification reactions, e.g. free fatty acids with methanol, and at higher temperatures, (60-100 °C): esterification of free fatty acids with hindered alcohols (isopropanol), addition of iodine to CC bonds, opening of oxygen(s) containing heterocyclic rings, selective substitution of primary OH groups to iodine in the presence of other functional groups or secondary alcohol groups, esterification of alcohols with nitriles (R-CN), transesterification of fatty acid triglycerides to biodiesel and selective derivatization of primary hydroxyl groups (-CH2OH) over secondary moieties of sugars without any protection. Most of the reactions were also performed by a re-used Dowex cation exchange resin.
Turhanen, Petri A.,Veps?l?inen, Jouko J.
p. 26218 - 26222
(2015/10/20)

A new approach for bio-jet fuel generation from palm oil and limonene in the absence of hydrogen
The traditional methodology includes a carbon-chain shortening strategy to produce bio-jet fuel from lipids via a two-stage process with hydrogen. Here, we propose a new solution using a carbon-chain filling strategy to convert C10 terpene and lipids to jet fuel ranged hydrocarbons with aromatic hydrocarbon ingredients in the absence of hydrogen.
Zhang, Jingjing,Zhao, Chen
p. 17249 - 17252
(2015/12/08)

METHOD FOR DECARBOXYLATION OF AMINO ACIDS VIA IMINE FORMATION
The present application provides methods for decarboxylation of amino acids via imine formation with a catalyst under superheated conditions in either a microwave or oil bath.
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Paragraph 0060

(2014/09/30)

High catalytic performance of palladium nanoparticles supported on multiwalled carbon nanotubes in alkene hydrogenation reactions
The synthesis of Pd nanoparticles (Pd-NPs) supported on multi-walled carbon nanotubes (MWCNTs) and the cataytic performance of the resulting material (Pd-NPs/MWCNTs) in hydrogenation reactions are presented. Facile preparation approaches based on the decomposition of Pd precursors in the presence of MWCNTs lead to homogeneous dispersions of supported Pd-NPs with an average size of 4 nm and Pd loads of about 12%. The catalytic performance of this material was evaluated in hydrogenation reactions of α,β-unsaturated ketones, alkenes, cyclic di-, tri- and tetraenes, aromatic compounds, terpenes and terpenoids, resulting in very high activity offering short reaction times, high conversion rates, notable selectivity, and acceptable recyclability under mild conditions.
Cano, Manuela,Benito, Ana M.,Maser, Wolfgang K.,Urriolabeitia, Esteban P.
p. 1968 - 1972
(2013/10/08)

Synthesis of 6-hydroxycarvone derivatives and their oxidative decyclization with lead tetraacetate
6-Hydroxy derivatives of R-(-)-carvone and 7,8-epoxycarvone were synthesized and subjected to oxidative ring cleavage by the action of lead tetraacetate. These reactions followed different patterns, depending on the substrate structure. Pleiades Publishing, Ltd., 2011.
Valeev,Bikzhanov,Selezneva,Gimalova,Miftakhov
experimental part
p. 1287 - 1292
(2011/12/04)

Advantageous heterogeneously catalysed hydrogenation of carvone with supercritical carbon dioxide
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.
Melo, Catarina I.,Bogel-Lukasik, Rafal,Da Silva, Marco Gomes,Bogel-Lukasik, Ewa
experimental part
p. 2825 - 2830
(2011/12/05)

Catalytic activity of iron-substituted polyoxotungstates in the oxidation of aromatic compounds with hydrogen peroxide
The tetrabutylammonium (TBA) salts of Keggin-type polyoxotungstates of the general formula [XW11FeIII(H2O)O39] n-, where X = P, B or Si, were evaluated as catalysts in the oxidation, under mild conditions, of ethylbenzene, cumene, p-cymene and sec-butylbenzene with aqueous H2O2 in CH3CN at 80 °C. The influence of various factors, such as the substrate/catalyst molar ratio, the amount of oxidant added or the reaction time, was investigated in a systematic way. Generally, the system exhibited moderate conversion, with good selectivity towards the corresponding acetophenone and hydroperoxide. In order to understand the reaction pathways, the oxidation of several products and presumed intermediates was also carried out in the presence of TBA 4[PW11Fe(H2O)O39]?2H 2O. Under the conditions used, the oxidation of styrene and styrene derivatives gave rise mainly to carbon-carbon double-bond cleavage, affording the corresponding products in very high yields (81-87%). Possible reaction pathways are presented.
Estrada, Ana C.,Simoes, Mario M. Q.,Santos, Isabel C. M. S.,Neves, M. Graca P. M. S.,Cavaleiro, Jose A. S.,Cavaleiro, Ana M. V.
experimental part
p. 1223 - 1235
(2011/09/12)

Desaturation of alkylbenzenes by cytochrome P450BM3 (CYP102A1)
A study was conducted to investigate the desaturation of alkylbenezenes by cytochrome P450BM3 (CYP102A1). It was observed during the study that oxidation of alkylbenzenes with CYP102A1 involves a gamut of P450 activity types that are terminal, sub-terminal benzylic and aromatic hydroxylation; terminal and sub-terminal desaturation; and epoxidation of the olefins. It was also found that the desaturation of cumene by CYP102A1 is sensitive to α-deuteration and insensitive to β-deuteration. Intramolecular deuterium isotope study revealed that the first abstraction in the desaturation of valproic acid and ezlopitant by microsomal P450s take place from activated carbon atoms. The increased β-hydroxylation percentages show that the β-carbon lies closer to the ferryl oxygen in the KT5.
Whitehouse, Christopher J.C.,Bell, Stephen G.,Wong, Luet-Lok
supporting information; scheme or table
p. 10905 - 10908
(2009/11/30)

Evolved CYP102A1 (P450BM3) variants oxidise a range of non-natural substrates and offer new selectivity options
The evolution of CYP102A1 variants with enhanced activity and altered specificity characteristics. The Royal Society of Chemistry.
Whitehouse, Christopher J. C.,Bell, Stephen G.,Tufton, Henry G.,Kenny, Richard J. P.,Ogilvie, Lydia C. I.,Wong, Luet-Lok
p. 966 - 968
(2008/09/21)

Using geminal dicationic ionic liquids as solvents for high-temperature organic reactions
(Chemical Equation Presented) Several organic reactions conducted at high temperatures, including the isomerization reaction, the Claisen rearrangement, and the Diels-Alder reaction, were investigated in three geminal dicationic ionic liquids with high thermal stability. High to moderate yields of the products for most entries were obtained. Advantages of these approaches are discussed. These ionic liquids were shown to be recyclable. The utility of these ionic liquid solvents for high-temperature organic reactions was demonstrated.
Han, Xinxin,Armstrong, Daniel W.
p. 4205 - 4208
(2007/10/03)

α- and β-thujone radical rearrangements and isomerizations. A new radical clock
Radical clocks have been extensively used in chemical and biochemical mechanistic studies. The C4 radicals of α- and β-thujone can undergo two distinct rearrangement reactions that could, in principle, serve as simultaneous but independent radical clocks. We have therefore generated these C4 radicals by photolysis of the corresponding N-hydroxypyridine-2-thione ester precursors and have investigated their fates and lifetimes. Photolysis of either α- or β-thujone generates the same 6:100 mixture of α- and β-thujone when the radicals are quenched by thiophenol. Hydrogen atom transfer from thiophenol to the radical thus occurs preferentially from the less sterically hindered α-face to give β-thujone. The third product formed in the photolysis via opening of the cyclopropyl ring is 2-methyl-5-isopropylcyclopent-2-enone. The ratio of ring opened to unopened products gives very similar values of krα = 4.4 × 10 7 S-1 and krβ = 1.0 × 108 S-1 for ring opening of the radicals generated from α- and β-thujone, respectively. If the C4 cation rather than radical is generated, it is converted to carvacrol, a phenol that is not obtained in the radical reactions. Thujone therefore differentiates between radical and cation pathways and provides a measure of the radical lifetime.
He, Xiang,Ortiz De Montellano, Paul R.
p. 5684 - 5689
(2007/10/03)

A practical route for the preparation of substituted 6-oxo-2-hexenoate derivatives
Reaction of 2-hydroxy-3-butenoates with a series of carbonyl derivatives gives substituted 6-oxo-2-hexenoates in good yields under mild acid conditions via Claisen rearrangement of the allyl alkenyl ether intermediate.
Freiría, Marta,Whitehead, Andrew J.,Motherwell, William B.
p. 805 - 808
(2007/10/03)

One-pot transformation of silyl enol ethers into 1,3-dienes: In situ generation of alkenyl nonaflates and subsequent Heck reactions - Scope and limitations
Palladium-catalysed reactions between methyl acrylate and the isolated alkenyl nonaflates 2a, 2d and 2e proceed without difficulties, furnishing the desired 1,3-dienes 3, 14 and 15 in good yields. The use of other alkenyl nonaflates and olefins in this Heck reaction was also examined. The main purpose of this study was the development of an in situ generation of the required alkenyl nonaflates 2 from the corresponding silyl enol ethers 1 and their one-pot transformation into 1,3-dienes. Thus, the previously described fluoride-promoted exchange of the trimethylsilyl substituent of typical enol ethers 1 for a nonafluorobutylsulfonyl group was directly combined with the palladium-catalysed coupling step. This sequence allowed the efficient transformation of a variety of silyl enol ethers 1 into highly substituted 1,3-dienes in a practical one-pot procedure. The scope and limitations, together with the chemo- and stereoselectivity, of this process are discussed. A particular intriguing example involves a one-pot synthesis of silyl enol ether 1j by means of a Diels-Alder reaction, subsequent nonaflation and a Heck reaction with tert-butyl acrylate, furnishing the highly functionalised 1,3-diene 30 in good overall yield. Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002.
Lyapkalo, Ilya M.,Webel, Matthias,Reissig, Hans-Ulrich
p. 3646 - 3658
(2007/10/03)

Compounds having protected hydroxy groups
The present invention relates to compounds with protected hydroxy groups of formula (I) These compounds are precursors for organoleptic agents, such as fragrances, and masking agents and for antimicrobial agents. When activated, the compounds of formula (I) are cleaved and form one or more organoleptic and/or antimicrobial compounds.
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(2008/06/13)

Salicylaldehyde-containing composition having antimicrobial and fragrancing properties and process for using same
Described are synergistic antimicrobial-fragrance compositions including broad spectrum antimicrobial compositions containing salicylaldehyde and at least one organoleptically-compatible antimicrobial synergism cofactor substance. The weight ratio range of salicylaldehyde:synergism cofactors substance is from 1:10 up to 10:1. The cofactor substance is such that the degree of synergism of the resultant mixture is defined according to the IFF Antimicrobial Synergism Test wherein the difference between the actual and expected antimicrobial values of the mixture is greater than or equal to a multiple of (i) 0.05 and (ii) the expected antimicrobial value of the mixture. Cofactor substances include phenolics such as cresol, caravacrol and thymol; ethyl vanillin; benzyl alcohol; indol; β-orcinol; and terpinenol-4. Microorganisms against which the synergistic compositions are effective include: Escherichia coli; Enterococcus hirae; Pseudomonas aeruginosa; Staphylococcus aureus;and Saccharomyces cerevisae. The compositions have application in all-purpose cleaning compositions, gel-type toilet rim articles, liquid-type toilet rim articles, personal shower cleaning compositions, and body and hair care products including shower gel compositions, shampoo compositions and foam bath compositions.
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(2008/06/13)

Microwave promoted selective preparation of acetals and esters from aldehydes
A new selective method of acetalization of aldehydes and cyclic ketones with 1,2-diols or alcohols catalyzed by iodine under microwave irradiation is reported. Depending upon the reaction conditions further oxidation of the arylidene acetals takes place in the system leading to the formation of products like iodoester 2 and hydroxy esters 3, 4 and 5. Both unsubstituted (1a) and substituted arylidene acetal with electron releasing group (1d) give high yield of iodoester 2 (70-80%) whereas the arylidene acetal substituted with an electron withdrawing group such as NO2 (1b) gives a low yield of the corresponding iodoester (2b, 25%).
Borah, Ruli,Kalita, Dipok J.,Sarma, Jadab C.
p. 1032 - 1038
(2007/10/03)

The Ritter reaction of terpenes. Part 3. Investigation of carvone and related compounds
The Ritter reaction of (R)-carvone (1), cis-carveol (2) and carvyl ethers 3 and 4 was investigated. For ketone 1 formation of 8-amido-6-p-menthen-2-ones (7-12) in moderate yields was observed. Alcohol 2 gave, depending on the reaction conditions, 2-amido-6,8(9)-p-menthadienes, 2-amido-4(8),6-p-menthadienes and/or 2,8-diamido-6-p-menthenes. Ethers 3 and 4 underwent cleavage to almost the same amides as it was observed for cis-carveol (2). Additionally, tertiary phenylcarveol (5) under similar conditions furnished 6-acetamido-2-phenyl-1,8(9)-p-menthadiene (28) as a result of dehydration, followed by migration of a double bond. The proposed mechanisms of the reactions are presented.
Welniak
p. 55 - 62
(2007/10/03)

Beta-ketoester compounds
The beta-ketoesters of formula I are useful as precursors for organoleptic compounds, especially for flavors, fragrances and masking agents and antimicrobial compounds.
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(2008/06/13)

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The aromatic hydroxyaldehydes 3a-3g, 5a-Sf, 8, 10 can be prepared by the action of BCl3, BBr3 or trifluoromethanesulfonic acid, on the aryl formates 1a-1f, 4a-e, 7, 9 via Fries rearrangement. BBr3 is more effective than BCl3. The activating ability of BBr3 can be improved by addition of FeCl3. Rearrangements which are induced by trifluoromethanesulfonic acid can give rise to the formations of regioisomers, which might be different from the products formed when the reaction is performed with Lewis acids. The yields of the aldehydes are lowered by subsequent condensation reactions. This view was confirmed by the isolation of a condensation product, which was characterized as a dibenzo[a,j]xanthene derivative 6 by crystal structure analysis. For the Fries rearrangement of formyl groups a new mechanism is proposed. 2-Hydroxy-1-naphthaldehyde 5c can be obtained in good yield from formic acid, BBr3, and 2-naphthol.
Ziegler, Georg,Haug, Erwin,Frey, Wolfgang,Kantlehner, Willi
p. 1178 - 1187
(2007/10/03)

Thermal degradation of terpenes: Camphene, Δ3-carene, limonene, and α-terpinene
Emissions from wood dryers have been of some concern for a number of years, and recent policy changes by the Environmental Protection Agency have placed emphasis upon the gaseous emissions that lead to the formation of particulate matter as small as 2.5 μm diameter. In this qualitative study, camphene, Δ3-carene, limonene, and α-terpinene were thermally degraded in the presence of air to determine the number and kind of oxidative degradation products that might be expected under drying conditions used in processing wood products. Various chromatographic methods were used to isolate the products for proof of structure by NMR and/or GC-MS. The degradation products resulted from dehydrogenations, epoxidations, double bond cleavages, allylic oxidations, and rearrangements. A number of compounds not previously associated with the thermal degradation of these terpenes were identified. Emissions from wood dryers have been of some concern for a number of years, and recent policy changes by the Environmental Protection Agency have placed emphasis upon the gaseous emissions that lead to the formation of particulate matter as small as 2.5 μm diameter. In this qualitative study, camphene, Δ3-carene, limonene, and α-terpinene were thermally degraded in the presence of air to determine the number and kind of oxidative degradation products that might be expected under drying conditions used in processing wood products. Various chromatographic methods were used to isolate the products for proof of structure by NMR and/or GC-MS. The degradation products resulted from dehydrogenations, epoxidations, double bond cleavages, allylic oxidations, and rearrangements. A number of compounds not previously associated with the thermal degradation of these terpenes were identified.
Mcgraw, Gerald W.,Hemingway, Richard W.,Ingram Jr., Leonard L.,Canady, Catherine S.,Mcgraw, William B.
p. 4029 - 4033
(2007/10/03)

A selective catalytic method of enol-acetylation under microwave Irradiation
Six-membered cyclic ketones on treatment with acetic anhydride and a catalytic amount of iodine under microwave irradiation give the corresponding enol acetates in good yield.
Kalita, Dipok J.,Borah, Ruli,Sarma, Jadab C.
p. 404 - 405
(2007/10/03)

Batch microwave reactor
An apparatus for performing batchwise chemical reactions using microwave energy (10-11-12) includes a vessel (15) within a microwave cavity (13). The vessel has a sealed cover (16), located outside cavity (13), which mounts a cold-finger type heat exchanger (24) for immersion in the vessel's contents (23). Cover (16) also mounts a pressure measuring device (17) and a temperature sensing device (20) for monitoring the vessel's contents during a chemical reaction. A pressure operable safety valve (18) and a sampling facility (19) are also mounted on the cover (16). The vessel also contains a magnetically operated stirrer (22). The reactor apparatus is constructed to withstand high pressures and temperatures that may be developed within the vessel (15). Various uses of the cold-finger (24) to facilitate the conduct or completion of a chemical reaction are described.
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(2008/06/13)

Applications of High-Temperature Aqueous Media for Synthetic Organic Reactions
Preparative organic synthesis was investigated in aqueous media at temperatures up to 300°C. Experiments were conducted with a recently disclosed pressurized microwave batch reactor (MBR) or in conventionally heated autoclaves. Thirty-six examples are presented. Among these, methods were developed for a Fischer synthesis, an intramolecular aldol condensation that was scaled up, decarboxylation of indole-2-carboxylic acid, Rupe rearrangement of 1-ethynyl-l-cyclohexanol, isomerization of carvone to carvacrol, and conversion of phenylacetylene to acetophenone. The applicability of high-temperature water was also demonstrated for biomimetic processes important in food, flavor, and aroma chemistry and for tandem reactions such as formation of 2-methyl-2,3- dihydrobenzofuran from allyl phenyl ether. When addition of acid or base was necessary, less agent was usually required for high-temperature processes than for those at and below boiling, and the reactions often proceeded more selectively. In some instances the requirement was orders of magnitude lower, with obvious consequences for safe, economic processing and for lowering costs of effluent disposal. The diversity of reactions indicates that high-temperature aqueous media could play an increasingly important role in the development of new preparative processes.
An, Jingyi,Bagnell, Laurence,Cablewski, Teresa,Strauss, Christopher R.,Trainor, Robert W.
p. 2505 - 2511
(2007/10/03)

Influence of a non-micelle-forming surfactant on the electrocatalytic hydrogenation of carvone and limonene in aqueous medium at Raney nickel electrodes
The electrocatalytic hydrogenation (ECH) of carvone (1) and limonene (8) at a Raney nickel cathode was studied in aqueous solutions containing a non-micelle-forming surfactant (didodecyldimethylammonium bromide, DDAB). The efficiency of ECH of these substrates was markedly increased compared to that observed previously with micelle-forming surfactants, and this for very low DDAB concentrations, as a consequence of strong adsorption of DDAB on the electrode. For the ECH of 8 in basic medium (pH 10), the major part of organic compounds (60-95%) was shown to be adsorbed on the electrode surface as an organic layer stabilized by an interfacial film of DDAB.
Beraud,Lessard,Thomalla
p. 1529 - 1535
(2007/10/03)

Trimethylchlorosilane and water. Convenient reagents for the regioselective hydrochlorination of olefins
The hydrochlorination of a series of simple and functionalized olefins in high yields was readily accomplished using a mixture of trimethylchlorosilane and water. Hydrochlorination by this procedure is chemoselective and regioselective.
Boudjouk, Philip,Kim, Beon-Kyu,Han, Byung-Hee
p. 3479 - 3484
(2007/10/03)

A New Microwave Reactor for Batchwise Organic Synthesis
A laboratory-scale microwave batch reactor (MBR) has been developed for organic synthesis or kinetic studies on the 20-100 mL scale, with upper operating limits of 260 deg C and 10 MPa (100 atm).The MBR complements a continuous microwave reactor which was the subject of a previous report from the author's laboratory.Microwave-assisted organic reactions were conducted safely and conveniently in the MBR, for lengthy periods when required, and in volatile organic solvents.The use of water as a solvent for organic reactions was also explored.Examples include oxidation, elimination, esterifications, hydrolysis of a tertiary amide, etherification, isomerization, Hofmann elimination, α-iodination of a carboxylic acid, Claisen rearrangement, aminoreductone formation, and Willgerodt reactions.Advantages of the new MBR include the capability for rapid heating and quenching of reaction mixtures, minimal temperature gradients within the sample, and elimination of wall effects.Safety aspects have been discussed.
Raner, Kevin D.,Strauss, Christopher R.,Trainor, Robert W.,Thorn, John S.
p. 2456 - 2460
(2007/10/02)