3858-49-9Relevant academic research and scientific papers
Simple H2-free hydrogenation of unsaturated monoterpenoids catalyzed by Raney nickel
Philippov, Alexey A.,Chibiryaev, Andrey M.,Martyanov, Oleg N.
, p. 380 - 381 (2019/08/20)
A series of monoterpenoids (citral, carvone, menthone, camphor) as well as cyclohexanone and hex-5-en-2-one were subjected to transfer hydrogenation with PriOH/Raney nickel system at 82 or 150 °C. Among monoterpenoids, citral and carvone underwent full conversion at 82 °C within 5 h.
P450-catalyzed regio- and stereoselective oxidative hydroxylation of disubstituted cyclohexanes: Creation of three centers of chirality in a single CH-activation event This paper is dedicated to the memory of Harry H. Wasserman
Ilie, Adriana,Agudo, Rubén,Roiban, Gheorghe-Doru,Reetz, Manfred T.
, p. 470 - 475 (2015/02/02)
Wild-type P450-BM3 is able to catalyze in a highly regio- and diastereoselective manner the oxidative hydroxylation of non-activated disubstituted cyclohexane derivatives lacking any functional groups, including cis- and trans-1,2-dimethylcyclohexane, cis- and trans-1,4-dimethylcyclohexane, and trans-1,4-methylisopropylcyclohexane. In all cases except chiral trans-1,2-dimethylcyclohexane as substrate, the single hydroxylation event at a methylene group induces desymmetrization with simultaneous creation of three centers of chirality. Certain mutants increase selectivity, setting the stage for future directed evolution work.
Radical chain reduction of alkylboron compounds with catechols
Villa, Giorgio,Povie, Guillaume,Renaud, Philippe
supporting information; experimental part, p. 5913 - 5920 (2011/06/16)
The conversion of alkylboranes to the corresponding alkanes is classically per-formed via protonolysis of alkylboranes. This simple reaction requires the use of severe reaction conditions, that is, treatment with a carboxylic acid at high temperature (>150 °C). We report here a mild radical procedure for the transformation of organoboranes to alkanes. 4-tert-Butylcatechol, a well-established radical inhibitor and antioxidant, is acting as a source of hydrogen atoms. An efficient chain reaction is observed due to the exceptional reactivity of phenoxyl radicals toward alkylboranes. The reaction has been applied to a wide range of organoboron derivatives such as B- alkylcatecholboranes, trialkylboranes, pinacolboronates, and alkylboronic acids. Furthermore, the so far elusive rate constants for the hydrogen transfer between secondary alkyl radical and catechol derivatives have been experimentally determined. Interestingly, they are less than 1 order of magnitude slower than that of tin hydride at 80 °C, making catechols particularly attractive for a wide range of transformations involving C-C bond formation.
Reduction of α, β-unsaturated ketones using a Zn/NiCl 2 system in aqueous media in the presence of anionic and cationic surfactants
Ilikti, Hocine,Benabdallah, Tayeb,Bentayeb, Kamel,Othman, Adil A.,Derriche, Zoubir
, p. 31 - 36 (2008/12/22)
The reduction of aromatic and aliphatic α,β-unsaturated ketones, namely acetophenone (1) and (-)-carvone (3) with a Zn/NiCl2 system in H2O or H2O/EtOH media in the absence or presence of anionic and cationic surfactants have been investigated and have shown remarkable results. The anionic sodium dodecyl sulphate (SDS), the cationic cetyltrimethylammonium bromide (CTAB) and the non-micelle-forming didodecyldimethylammonium bromide (DDAB) surfactants were utilized. The reduction of acetophenone in H2O medium gave only a low yield of 1-phenyl ethanol (2) in comparison with the yields which resulted when a H 2O/EtOH medium was employed. The yields increased relatively in a H2O medium in the presence of cationic surfactants which showed a gradual increase at low concentrations following different patterns and sharp increases at 60 °C and pH9. The reduction of (-)-carvone (3) with the same system in H2O medium gave relatively higher yields than that of acetophenone. In the presence of cationic surfactants CTAB and DDAB in aqueous medium the total reduction yield increased appreciably and sometimes reached 100 % in the presence of DDAB at a concentration of 0.98 × 10-2 mol L-1 at 60 °C. The effects of pH, combined metallic salts and different surfactant concentrations on the reduction of (-)-carvone have been also investigated. This paper focuses on the application of surfactants in the reduction of α,β-enones by metal/metallic chloride/H2O systems in the absence of organic solvents. This method displays regioselectivity and stereoselectivity. This method may also be considered as a contribution to the antipollution process by means of the elimination of organic solvents from the chemical process.
Antimicrobial therapeutic compositions for oral and topical use
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Page 7; 18, (2008/06/13)
The invention provides therapeutic antimicrobial compositions comprising natural phenolic compounds and essential oil alcohols and methods of use. The therapeutic antimicrobial compositions are useful to treat internal and external bacterial, fungal, and protozoan infections, as well as antibiotic resistant and secondary opportunistic infections.
Influence of a non-micelle-forming surfactant on the electrocatalytic hydrogenation of carvone and limonene in aqueous medium at Raney nickel electrodes
Beraud,Lessard,Thomalla
, p. 1529 - 1535 (2007/10/03)
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.
Enantioselectivity in the Biotransformation of Mono- and Bicyclic Monoterpenoids with the Cultured Cells of Nicotiana tabacum
Hamada, Hiroki
, p. 869 - 878 (2007/10/02)
The biotransformation of the enantiomeric pairs of p-menthane and bicyclo and heptane derivatives with the cultured cells of Nicotiana tabacum was investigated.It was found that (i) the cultured cells discriminate the enantiomers of p-menthan-2-ol and bicycloheptan-2-ol and bicycloheptan-3-ol derivatives, and enantioselectively convert these alcohols to the corresponding ketones, (ii) the cells reduce the carbonyl group of p-methan-2-one derivatives to a high extent, but not that of p-menthan-3-ones, and (iii) the cells discriminate the enantiomers of bicyclohept-2-en-4-one (verbenone) and enantioselectively reduce the C-C double bond of the (1S,5S)-enantiomer.
Terpenoid Ether Formation in Superacids
Carr, Graham,Dean, Cristopher,Whittaker, David
, p. 351 - 354 (2007/10/02)
A number of terpenoid bicyclic ethers have been prepared by cyclisation of suitable precursors in fluorosulphuric acid-sulphur dioxide.The products are formed under a mixture of thermodynamic and kinetic control, and five-, and six-, and seven-membered-ring ethers are obtained.Both primary and secondary alcohols have been cyclised by attack of the hydroxy group on carbocation centres generated by protonation of alkenes or ionisation of tertiary alcohols; tertiary alcohols ionise too readily to provide an etheral oxygen atom.Reaction of the unsaturated secondary alcohol dihydrocarveol (2) with antimony pentafluoride in sulphur dioxide gives the ether by a reaction which may not involve a carbocation, and hence may be suitable for ether formation from substrates which rearrange readily in acids.
Oxidoreduction between Cycloalkanols and Cycloalkanones in the Cultured Cells of Nicotiana tabacum. Simulation of the Time-courses in the Oxidation of (+)-Borneol and the Reduction of (-)-Carvomenthone
Suga, Takayuki,Izumi, Shunsuke,Hirata, Toshifumi,Hamada, Hiroki
, p. 425 - 428 (2007/10/02)
The time-courses in the oxidation of (+)-borneol and the reduction of (-)-carvomenthone in the cultured cells of Nicotiana tabacum were simulated on the basis of the permeability of 5- to 7-membered cycloalkanols and their corresponding cycloalkanones into the cultured cells and the 13C NMR chemical shifts of the carbonyl carbon of (+)-camphor which is the oxidation product of (+)-borneol and (-)-carvomenthone which is a substrate for the reduction, respectively.
Stereoselectivity in Oxidative and Reductive Transformations of p-Menthane Derivatives with the Cultured Cells of Nicotiana tabacum
Suga, Takayuki,Hamada, Hiroki,Hirata, Toshifumi,Izumi, Shunsuke
, p. 903 - 906 (2007/10/02)
The biotransformation of the enantiomeric pairs of 2- and 3-oxygenated p-methane derivatives with the cultured cells of Nicotiana tabacum was investigated.It was found that (I) the cultured cells transform only 2-oxygenated p-menthane derivatives to a great extent, (ii) the cultured cells cause the highly stereospecific reduction for (1R,4R)-2-oxo-p-menthane, whereas this is not the case for its enantiomer, and (iii) the cultured cells enantioselectively oxidize the hydroxyl group of 2-hydroxyl-p-methanes.
