3858-43-3Relevant 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.
Antimicrobial therapeutic compositions for oral and topical use
-
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.
Reduction of Organic Compounds with Rare-Earth Intermetallics Containing Absorbed Hydrogen
Imamoto, Tsuneo,Mita, Takeshi,Yokoyama, Masataka
, p. 5695 - 5699 (2007/10/02)
The hydrogenation of organic compounds with rare-earth intermetallic hydrides has been investigated.Alkynes,alkenes,aldehydes,ketones,nitriles,imines, and nitro compounds are hydrogenated in excellent yields with LaNi5H6 or LaNi4.5Al0.5H5 at 0-60 deg C.The present hydrogenation method has the following characteristic features. (1) The intermetallic compounds (alloys) are not poisoned by compounds containing an amino group or a halogen atom. (2) The alloys can be used repeatedly without decrease in activity. (3) The reaction conditions are mild, and selective hydrogenations of some organic functional groups can be achieved.The reaction mechanism of this hydrogenation is briefly discussed in terms of stereochemistry and H/D exchange reactions.
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.
