7077-04-5Relevant academic research and scientific papers
Catalytic hydrogenation products of aromatic and aliphatic dicarboxylic acids
Shinde, Sunil B.,Deshpande, Raj M.
, p. 1137 - 1142 (2019/04/05)
Hydrogenation of aromatic dicarboxylic acids gave 100 % selectivity to respective cyclohexane dicarboxylic acid with 5 % Pd/C catalyst. 5 % Ru/C catalyst was observed to give over hydrogenation products at 493 K and at lower temperature (453 K) the selectivity for cyclohexane dicarboxylic acids was increased. Hydrogenation of phthalic acid with Ru-Sn/Al2O3 catalyst was observed to give phthalide instead of 1,2-benzene dimethanol or 2-hydroxy methyl benzoic acid. Ru-Sn/Al2O3 catalyst selectively hydrogenated the carboxylic group of cyclohexane dicarboxylic acids to give cyclohexane dimethanol. Use of proper catalysts and reaction conditions resulted in desired products.
Epimerization of 2- or 4- substituted cyclohexanecarboxylic acids
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, (2008/06/13)
The present invention relates to a new method for obtaining a purity of about 93% to 100% of the trans form of 2- or 4-substituted cyclohexanecarboxylic acid or reactive derivatives thereof from the cis form or a mixture of the cis and trans forms by a single step, particularly, to a method for obtaining a purity of substantially 100% of the trans form of 4-substituted cyclohexanecarboxylic acid.
Selective heterogeneous palladium-catalyzed hydrogenations of watersoluble alkenes and alkynes
Tour, James M.,Pendalwar, Shekhar L.
, p. 4719 - 4722 (2007/10/02)
Treatment of water-soluble alkenes or alkynes with palladium(II) acetate and triethoxysilane at room temperature afforded the corresponding hydrogenated products in high yields. Simple introduction of a stoichiometric amount of hydrogen is accomplished by using triethoxysilane as the hydrogen source.
Lactone Formation in Superacidic Media
Carr, Graham,Whittaker, David
, p. 1877 - 1880 (2007/10/02)
The reaction of substituted 1-hydroxycyclohexanecarboxylic acids in fluorosulphuric acid has been studied.Cyclisation takes place around 0 deg C, accompanied by rearrangement in appropriate cases, yielding the thermodynamically stable lactone or mixture of lactones.An unexpected feature of these reactions is that the carboxy-substituted cyclohexyl carbocation does not undergo ring contraction, unlike the unsubstituted cyclohexyl carbocation, although the cycloheptyl system contracts to cyclohexyl.We suggest that the cyclohexyl carbocation is strongly stabilised by carboxyl substitution, as a result of through-space interaction between the carboxyl oxygen atom and the carbocation centre.
Poly(ethylene glycol) Promoted Reactions of Vinylic Dibromides. Dehydrohalogenation and Palladium(0)-Catalyzed Formal Oxidative Homologation
Li, Pei,Alper, Howard
, p. 4354 - 4356 (2007/10/02)
Aldehydes are converted to the homologous acids by a simple two-step procedure involving initial generation of a vinylic dibromide followed by Pd(diphos)2 catalyzed, poly(ethylene glycol) induced reaction with base.This reaction is useful for aromatic and α,β-unsaturated aldehydes and is also applicable to cyclic as well as alkyl aryl ketones. 1-Bromoalkynes are formed in good yields when the vinylic dibromide reaction is effected in the absence of the palladium(0) catalyst.
Stereochemistry of Decarbalkoxylation of Cyclic Geminal Diesters Effected by Water and Lithium Chloride in Me2SO
Krapcho, A. Paul,Weimaster, John F.
, p. 4105 - 4111 (2007/10/02)
The stereochemical consequences of the decarbalkoxylation of cyclic geminal diesters by LiCl-H2O-Me2SO have been examined.The norbornene diester 13 and the norbornane diester 16 lead predominantly to the exoesters 14 and 17, respectively.The 2-methylcyclohexane diester 22 leads to esters containing more cis (23) than trans (24) isomer.The diesters 19,25, and 28 lead to nearly equal amounts of the cis and trans esters.In these latter cases,the enolates generated from the esters (via LDA) are protonated in a nonstereoselective fashion on quenching with water.This is suggestive of an enolate intermediate in the decarbalkoxylation reaction.The implications of these sterochemical results are discussed.
Stereochemistry of Alkylation of Carboxylic Acid Salt and Ester α Anions Derived from Cyclic Systems.
Krapcho, A.Paul,Dundulis, Edward A.
, p. 3236 - 3245 (2007/10/02)
A stereochemical study of the alkylation of α-lithiated carboxylate salts and esters has been performed.The α anions derived from the bicyclic acids exo-1, endo-1, and 7 (R=H) and the esters 4 and 7 (R=CH3) yield predominantly exo alkylation.As an example, the α anion derived from ester 7 (R=CH3) on treatment with CH3I yields exo-8 (R=R'=CH3) and endo-9 (R=R'=CH3) in a 97:3 ratio, a highly stereoselective reaction.Addition of TMEDA to the reactions involving the α anions derived from exo- or endo-1 did not change the stereochemical alkylation results.The α anions derived from the substituted cyclohexanecarboxylic acids 10, 13, 16, 19, or 22 (where R=H in each case) on methylation yield more axial methylation (axial/equatorial ratios of 0.4-2.7) than the α anions derived from the methyl esters corresponding to these acids.The α anions from the esters yield predominantly equatorial methylated products (e/a ratios varying from 4 to 9).The reasons for the different stereochemical results are discussed.
