- Oxidative Esterification of Aldehydes and Alcohols Catalyzed by Camphor-Based Imidazolium Salts
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Abstract: Sixteen new camphor-based imidazolium salts have been synthesized with renewable camphorsulfonic acid as the starting material. The chemical shifts of the characteristic proton of C2 on the imidazolium ring (N?C=N) were discussed thoroughly and all of these imidazolium salts exhibit good thermal stability. Furthermore, the excellent catalytic performance of the synthesized imidazolium salts were observed in the oxidative esterification between aromatic or aliphatic aldehydes containing electron-withdrawing or electron-donating groups on aromatic ring and primary or secondary alcohol by air as the sole oxidant. Graphic Abstract: [Figure not available: see fulltext.].
- Bian, Tiancen,Feng, Li,Li, Danfeng,Huang, Jiaxin,Zhao, Yuxun,Xu, Xu,Yang, Yiqin,Wang, Shifa
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p. 1812 - 1820
(2020/01/11)
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- Camphoryl imidazole type ionic liquid and preparation method and application thereof
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The invention discloses a camphoryl imidazole type ionic liquid and a preparation method and application thereof. According to the preparation method, a derivative camphorsulfonic acid of a natural renewable resource camphor is taken as a raw material to prepare 10-iodocamphor; then the 10-iodocamphor and aryl imidazole are subjected to a quaterisation reaction to prepare camphoryl imidazole iodide; then the camphoryl imidazole iodide and sodium hexafluorophosphate, sodium tetrafluoroborate, bis(trifluorosulfonimide)lithium and the like are subjected to ion exchange to prepare camphoryl imidazole hexafluorophosphate, camphoryl imidazole tetrafluoroborate, camphoryl imidazole bis(trifluorosulfonimide)salt and other ionic liquids. The camphoryl imidazole type ionic liquid shows good catalytic activity for an oxidation esterification reaction of aldehyde-alcohol, has the advantages of short reaction time, good reaction selectivity and high product yield, and has a good application prospect.
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Paragraph 0060; 0064
(2019/10/05)
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- Efficient synthesis of esters through oxone-catalyzed dehydrogenation of carboxylic acids and alcohols
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Since esters are important organic synthesis intermediates, an environmentally friendly oxone catalyzed-esterification of carboxylic acids with alcohols has been developed. A series of carboxylic acid esters are obtained in high yield. This strategy requires mild reaction conditions, providing an attractive alternative for the construction of valuable carbonyl esters. Electron-rich and electron-deficient groups are compatible with the standard conditions and a variety of substrates are demonstrated. Moreover, the reaction could easily be adapted to typical prodrugs, drugs and gram-scale synthesis.
- Hou, Fei,Wang, Xi-Cun,Quan, Zheng-Jun
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supporting information
p. 9472 - 9476
(2019/01/03)
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- Facile Coupling of Aldehydes with Alcohols: An Evolved Tishchenko Process for the Preparation of Unsymmetrical Esters
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A facile coupling process between aldehydes and alcohols to afford unsymmetrical esters is presented herein. This transformation is complementary to the Tishchenko reaction and provides access to unsymmetrical esters under very mild conditions. Various aldehydes and alcohols are suitable in this reaction, and the addition of a sacrificial trifluoromethyl ketone allows the process to take place in a highly selective manner. A plausible mechanism based on details obtained by monitoring the reaction progress and deuterium-labeling studies has been proposed.
- Liu, Heng,Eisen, Moris S.
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p. 4852 - 4858
(2017/09/07)
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- Selective Actinide-Catalyzed Tandem Proton-Transfer Esterification of Aldehydes with Alcohols for the Production of Asymmetric Esters
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Actinide-catalyzed tandem proton-transfer esterification between aldehydes and alcohols is presented herein for the first time. It represents a novel convenient and external-oxidant-free methodology in the preparation of asymmetric ester compounds. Various kinds of aldehydes and alcohols can be applied to this reaction, affording the corresponding ester product in moderate to high yields. A plausible mechanism was proposed on the basis of the kinetic, stoichiometric, and deuterium-labeling studies.
- Liu, Heng,Eisen, Moris S.
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supporting information
p. 1461 - 1464
(2017/04/28)
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- Carbon-carbon bond cleavage and esterification of phenylacetonitrile and its derivatives affording the corresponding benzoic esters
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Phenylacetonitrile and its derivatives were treated with alcohols in the presence of potassium iodide and iodine affording the corresponding benzoate esters via degradation, oxidation and esterification under mild conditions. The products were characterised by IR, 1H NMR, MS and elemental analysis.
- Wang, Zhiyuan,Kang, Junhui,Yu, Mingxin
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p. 323 - 324
(2008/02/10)
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- A facile direct conversion of aldehydes to esters and amides using acetone cyanohydrin
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Aromatic aldehydes with electron-withdrawing groups undergo rapid reactions with a variety of alcohols and secondary amines to afford the corresponding esters and amides, respectively, in high yields, when treated with NaCN or acetone cyanohydrin and base under ambient reaction conditions. In case of α,β-unsaturated aldehydes, simultaneous reduction of the CC bond along with esterification occurred to produce the saturated esters in high yields.
- Raj, I. Victor Paul,Sudalai
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p. 8303 - 8306
(2007/10/03)
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- Oxidative conversion of aldoximes into carboxylic acid esters catalysed by polystyrene-bound phenylseleninic acid
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Aromatic and aliphatic aldoximes were catalytically oxidised to carboxylic acid esters in good to moderate yields with hydrogen peroxide as oxidant using polystyrene-bound phenylseleninic acid as catalyst.
- Sheng, Shou-Ri,Huang, Xian
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p. 491 - 492
(2007/10/03)
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