1195-93-3Relevant academic research and scientific papers
N,N′-Dichlorobis(2,4,6-trichlorophenyl)urea (CC-2): An efficient reagent for conversion of oximes to ketones
Gupta, Arvind K.,Acharya, Jyotiranjan,Pardasani, Deepak,Dubey, Devendra K.
, p. 411 - 414 (2008/02/12)
A method for the rapid conversion of oximes into the corresponding carbonyl compounds using N,N′-dichlorobis (2,4,6-trichlorophenyl)urea (CC-2) at room temperature is described. The method is economical as the solid by-product bis(2,4,6-trichlorophenyl)urea could be removed by filtration and recycled after re-chlorination.
Investigations into the selective oxidation of vicinal diols to α-hydroxy ketones with the NaBrO3/NaHSO3 reagent: PH dependence, stoichiometry, substrates and origin of selectivity
Bierenstiel, Matthias,D'Hondt, Paul J.,Schlaf, Marcel
, p. 4911 - 4917 (2007/10/03)
The NaBrO3/NaHSO3 reagent is one of the few oxidizing agents that chemoselectively oxidizes vicinal diols to α-hydroxy ketones with little overoxidation to the corresponding vicinal-dione or dicarboxylic acid. Oxidation reactions performed with this reagent showed strong pH dependence. cis-Vicinal diols reacted faster than trans-vicinal diols to the α-hydroxy ketone product. Hydroxy functional groups at axial ring positions were more readily oxidized than equatorial hydroxy groups. The application of the NaBrO3/NaHSO3 reagent for the chemoselective oxidation of vicinal diols was limited to simple systems and failed with more complex monosaccharide compounds probably due to acid catalyzed dehydrogenation reactions. Despite the simple reaction set-up and good selectivity towards the α-hydroxy ketone product, the actual oxidation reaction mechanism is highly complex and postulated to involve at least six different equilibria with a plethora of bromine containing species. A possible oxidation reaction mechanism is discussed.
Ozonolyses of 1-alkyl-substituted 1-tert-butylethylenes and highly methylated methylenecycloalkanes. The influence of the substituent steric bulk on the direction of cleavage of the primary ozonides
Kawamura, Shin-Ichi,Yamakoshi, Hideyuki,Abe, Manabu,Masuyama, Araki,Nojima, Masatomo
, p. 891 - 896 (2007/10/03)
Ozonolyses of 1-alkyl-substituted 1-tert-butylethylenes and of highly methylated methylenecycloalkanes were conducted in the presence of trifluoroacetophenone (7) in ether. The ozonolysis of 2,2,6-trimethyl-1-methylenecyclohexane provided only the crossed-ozonide 10 derived from capture of formaldehyde O-oxide with the ketone 7 in 42% yield, while in the case of the relevant 2,2,5-trimethyl-1-methylenecyclopentane the alternative crossed-ozonide 15e derived from cycloaddition of 2,2,5-trimethylcyclopentanone O-oxide with the ketone 7 was the sole isolable product. The total energies of two possible cycloreversion processes for the primary ozonide 12c and for 12e, calculated at B3LYP/6-31G**//B3LYP/3-21G* level of theory, seem to reproduce the observed difference in the regiochemistry of fragmentation between these two primary ozonides.
Oxidation of α-Substituted Cyclohexanols by Nitric Acid
Smith, John R. Lindsay,Thomas, C. Barry,Whittaker, Mark
, p. 2191 - 2194 (2007/10/02)
The influence of α-substituents on the oxidative cleavage of cyclohexanol by nitric acid in the presence of copper(II) and vanadium(V) ions has been investigated.Following the initial oxidation to give the cyclohexanone, further reaction, leading to ring opening of the ketone, requires at least one α-hydrogen.Thus 2,2,6,6-tetramethylcyclohexanol is converted to the corresponding ketone whilst 2,2,6-trimethylcyclohexanol is oxidised to a mixture of dicarboxylic acids.The mechanisms of the oxidations are discussed and enolisation is shown to be the key to oxidative cleavage.For ketones that can give two alternative enols, reaction occurs predominantly via the more stable tautomer.
The chemistry of thujone. XVI. Versatile and efficient routes to safronitrile, β-cyclogeranonitrile, β-cyclocitral, damascones, and their analogues
Kutney, James P.,Gunning, Philip J.,Clewley, Robin G.,Somerville, John,Rettig, Steven J.
, p. 2094 - 2114 (2007/10/02)
Thujone, a waste by-product of the Canadian forest industry, has been utilized as a starting material to develop a versatile synthetic route to the damascones (rose oil ketones) and related analogues.The synthetic sequence provides a route to β-cyclocitral (45), the latter having been previously converted to β-damascone (2).In addition, thujone-drived intermediates are converted to β-damascenone (48) and to intermediates that can be utilized for the preparation of damascone analogues.In conjunction with the above, an efficient route to safronitrile (42), β-cyclogeranonitrile (43), and β-cyclocitral (45) from 2,6-dimethylcyclohexanone has been developed.In summary, these studies afford an attractive versatile route to these important perfumery materials.
ALKYLATION OF KETONES BY USE OF SOLID KOH IN DIMETHYLSULFOXIDE
Langhals, Elke,Langhals, Heinz
, p. 859 - 862 (2007/10/02)
A mixture of solid KOH in dimethyl sulfoxide has a strong basicity, but only a low nucleophilicity and is used for α-methylation of ketones.With this simple and inexpensive reagent complete methylation with yields up to 90percent can be achieved.
A Convenient Procedure for Complete Methylation of the α-Positions of Some Ketones
Lissel, Manfred,Neumann, Beate,Schmidt, Stefan
, p. 263 - 264 (2007/10/02)
2,2,6,6-Tetramethylcyclohexanone (2a), Pivalophenone (4a), and other complete methylated ketones can be prepared by a simple procedure.Therefore the ketone was treated with methyl iodide and powdered KOH in the presence of catalytical amounts of crown-6.
Steric and Stereoelectronic Effects in the Hydrogenolysis and Birch Reduction of Some Hindered Tertiary-Benzylic Carbinols
Collins, David J.,Jacobs, Howard A.
, p. 1989 - 2004 (2007/10/02)
3-(4'-Methoxyphenyl)pentan-3-ol (3a) and 3-(4'-methoxyphenyl)-2,4-dimethylpentan-3-ol (3b) underwent catalytic hydrogenolysis over 10percent palladium/charcoal at moderate temperatures and pressures.The more hindered tertiary-benzylic carbinols 3-(4'-methoxyphenyl)-2,2,4-trimethylpentan-3-ol (6), 3-(4'-methoxyphenyl)-2,2,4,4-tetramethylpentan-3-ol (3c), 1-(4'-methoxyphenyl)-2,2,6,6-tetramethylcyclohexan-1-ol (8) and 1-(1',1'-dimethylethyl)-6-methoxy-2,2-dimethyl-1,2,3,4-tetrahydronaphthalen-1-ol (10) were completely resistant to hydrogenolysis, even under vigorous conditions.While the hindered tertiary-benzylic carbinols (6), (8) and (10) readily underwent Birch reduction, the analogous di-t-butyl anisyl carbinol (3c) was unchanged.The failure of (3c) to undergo Birch reduction is probably due to a hitherto unrecognized stereoelectronic effect: the C-OH bond of (3c) is constrained to lie more or less in the plane of the benzene ring, and addition of an electron to the benzene ring of the derived oxyanion (31) is inhibited in this conformation.
ENANTIOSELECTIVE CARBOXYLATION OF A PROCHIRAL ENOLATE IN THE PRESENCE OF A CHIRAL LITHIUM AMIDE
Hogeveen, H.,Menge, W. M. P. B.
, p. 2767 - 2770 (2007/10/02)
The prochiral lithium 2,2,6-trimethylcyclohexenolate (2) was prepared from ketone 1 by deprotonation with lithium (S,S)-α,α'-dimrthyldibenzylamide (4).Reaction of 2 with carbon dioxide at low temperature followed by methylation with methyl iodide yielded
