1871-67-6Relevant academic research and scientific papers
Reaction of a lysyl residue analogue with E-2-octenal
Alaiz, Manuel,Barragan, Santiago
, p. 43 - 50 (1995)
The reaction of E-2-octenal and N2-(carbobenzyloxy)-L-lysine was investigated and the products analyzed to identify the components that produce a significant loss of lysine residues in the reaction of E-2-octenal and proteins. When the mixture of N2-(carbobenzyloxy)-L-lysine and E-2-octenal was incubated at pH 7.0 and 37 deg C for 24 h, seven products were isolated, and their structures are suggested to be E-2-octenoic acid (4), 4-butyl-E-2-E-4-E-6-dodecatrien-1-al (3), 6-ethyl-5-pentyl-1,3-cyclohexadiene (1), 3,8-dibutyl-1-(2'-butyl-4'-formyl-1'-E-3'-E-butadien-1'-yl) -5-pentyl-2,6-dihydronaftalene (2), 1-(N2-(carbobenzyloxy)-L-lysyl)-2-(1'-carboxymethyl)-4-pentylpyridinium betaine (6), 1-(N2-(carbobenzyloxy)-L-lysyl)-2-(3'-carboxy-2'-E-propen-1'-yl)-4-pentylpyridinium betaine (7) and bis(1-(N2-(carbobenzyloxy)-L-lysyl)-2-(3'-carboxy-2'-propen-1',2'-diyl)-4-pentylpyridinium betaine) (5). Plausible mechanisms for the formation of those compounds are proposed. Keywords: N2-(Carbobenzyloxy)-L-lysine; E-2-Octenal; Pyridinium salts; Reaction
Ligand-controlled divergent dehydrogenative reactions of carboxylic acids via C–H activation
Wang, Zhen,Hu, Liang,Chekshin, Nikita,Zhuang, Zhe,Qian, Shaoqun,Qiao, Jennifer X.,Yu, Jin-Quan
, p. 1281 - 1285 (2021/12/10)
Dehydrogenative transformations of alkyl chains to alkenes through methylene carbon-hydrogen (C–H) activation remain a substantial challenge. We report two classes of pyridine-pyridone ligands that enable divergent dehydrogenation reactions through palladium-catalyzed b-methylene C–H activation of carboxylic acids, leading to the direct syntheses of a,b-unsaturated carboxylic acids or g-alkylidene butenolides. The directed nature of this pair of reactions allows chemoselective dehydrogenation of carboxylic acids in the presence of other enolizable functionalities such as ketones, providing chemoselectivity that is not possible by means of existing carbonyl desaturation protocols. Product inhibition is overcome through ligand-promoted preferential activation of C(sp3)–H bonds rather than C(sp2)–H bonds or a sequence of dehydrogenation and vinyl C–H alkynylation. The dehydrogenation reaction is compatible with molecular oxygen as the terminal oxidant.
Method for preparing alpha, beta-unsaturated carboxylic acid by reacting alkenyl boron compound with carbon dioxide under catalysis of cuprous halide
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Paragraph 0061-0062, (2020/06/17)
The invention discloses a method for preparing alpha, beta-unsaturated carboxylic acid through a carboxylation reaction of an alkenyl boron compound and carbon dioxide under the catalysis of cuprous halide. According to the method, carbon dioxide is used as a C1 source, the cuprous halide is adopted for catalysis, and alkoxide serves as alkali to react in an organic solvent, so the method is simple and easy to implement, has a wide substrate application range, converts various alkenyl boron compounds such as alkenyl boric acid, alkenyl borate and borate into corresponding alpha, beta-unsaturated carboxylic acid under mild conditions, and has a very high yield. The obtained product alpha, beta-unsaturated carboxylic acid is an important intermediate for preparing fine chemical products suchas perfumes, insecticides and the like.
Carboxylation of Alkenyl Boronic Acids and Alkenyl Boronic Acid Pinacol Esters with CO2 Catalyzed by Cuprous Halide
Hong, Junting,Nayal, Onkar S.,Mo, Fanyang
supporting information, p. 2813 - 2818 (2020/05/16)
A cuprous halide catalysed carboxylation of alkenyl boronic acids and alkenyl boronic acid pinacol esters under CO2, affording the corresponding α, β-unsaturated carboxylic acids in good yield, has been developed. The potassium (E)-trifluoro(styryl)borate is also compatible with this reaction. This simple and efficient copper(I) catalytic system showed good functional group tolerance.
Preparation method of (E, Z)-2, 4-ethyl decadienoate
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Paragraph 0040; 0041, (2019/05/15)
The invention provides a preparation method of (E, Z)-2, 4-ethyl decadienoate. According to the preparation method, n-hexyl aldehyde is taken as an initial raw material, and three step chemical conversion is adopted to prepare a key intermediate 1-bromo heptene; 1-bromo heptene and ethyl acrylate are subjected to coupling reaction under the catalytic effect of a metal catalyst so as to obtain (E,Z)-2, 4-ethyl decadienoate. According to the preparation method, metal catalytic coupling reaction is adopted to replace a step in the prior art that (E, Z)-2, 4-ethyl decadienoate is prepared throughpreparation of an organic copper lithium reagent, water-free oxygen-free harsh conditions are avoided, operation is simplified, reaction efficiency is increased, generation of waste water and waste salt is reduced greatly, equipment investment is reduced, and the preparation method is convenient for industrialization production.
Mild and versatile potassium fluoride/tetrabutylammonium fluoride protocol for ester hydrolysis
Vijayalakshmi,Balakrishna,Mustafa, Shaik
, p. 309 - 311 (2018/01/11)
A mild and versatile protocol of potassium fluoride/tetrabutylammonium fluoride (KF/TBAF) in aqueous tetrahydrofuran for ester hydrolysis has been developed. The method is applied on variety of aliphatic and aromatic ester moieties bearing acid or base sensitive functional groups. The conditions have been also applied on acetates to yield alcohols. The chirality of optically pure esters remained intact with the conditions of the reaction.
Unexpected AChE inhibitory activity of (2E)α,β-unsaturated fatty acids
Loesche, Anne,Wiemann, Jana,Al Halabi, Zayan,Karasch, Julia,Sippl, Wolfgang,Csuk, René
supporting information, p. 3315 - 3319 (2018/09/17)
A small library of (E) α,β-unsaturated fatty acids was prepared, and 20 different saturated and mono-unsaturated fatty acids differing in chain length were subjected to Ellman's assays to determine their ability to act as inhibitors for AChE or BChE. While the compounds were only very weak inhibitors of BChE, seven molecules were inhibitors of AChE holding IC50 = 4.3–12.8 M with three of them as significant inhibitors of this enzyme. The results have shown trans 2-mono-unsaturated fatty acids are better inhibitors for AChE than their saturated analogs. Furthermore, the screening results indicate that the chain length is crucial for obtaining an inhibitory efficacy. The best results were obtained for (2E) eicosenoic acid (14) showing inhibition constants Ki = 1.51 ± 0.09 M and Ki′ = 7.15 ± 0.55 M. All tested compounds were mixed-type inhibitors with a dominating competitive part. Molecular modelling calculations indicate a different binding mode of active/inactive compounds for the enzymes AChE and BChE.
Synthesis of α,β-unsaturated aldehydes as potential substrates for bacterial luciferases
Brodl, Eveline,Ivkovic, Jakov,Tabib, Chaitanya R.,Breinbauer, Rolf,Macheroux, Peter
, p. 1487 - 1495 (2017/02/18)
Bacterial luciferase catalyzes the monooxygenation of long-chain aldehydes such as tetradecanal to the corresponding acid accompanied by light emission with a maximum at 490?nm. In this study even numbered aldehydes with eight, ten, twelve and fourteen carbon atoms were compared with analogs having a double bond at the α,β-position. These α,β-unsaturated aldehydes were synthesized in three steps and were examined as potential substrates in vitro. The luciferase of Photobacterium leiognathi was found to convert these analogs and showed a reduced but significant bioluminescence activity compared to tetradecanal. This study showed the trend that aldehydes, both saturated and unsaturated, with longer chain lengths had higher activity in terms of bioluminescence than shorter chain lengths. The maximal light intensity of (E)-tetradec-2-enal was approximately half with luciferase of P. leiognathi, compared to tetradecanal. Luciferases of Vibrio harveyi and Aliivibrio fisheri accepted these newly synthesized substrates but light emission dropped drastically compared to saturated aldehydes. The onset and the decay rate of bioluminescence were much slower, when using unsaturated substrates, indicating a kinetic effect. As a result the duration of the light emission is doubled. These results suggest that the substrate scope of bacterial luciferases is broader than previously reported.
Allyl-Palladium-Catalyzed α,β-Dehydrogenation of Carboxylic Acids via Enediolates
Zhao, Yizhou,Chen, Yifeng,Newhouse, Timothy R.
supporting information, p. 13122 - 13125 (2017/09/13)
A highly practical and step-economic α,β-dehydrogenation of carboxylic acids via enediolates is reported through the use of allyl-palladium catalysis. Dianions underwent smooth dehydrogenation when generated using Zn(TMP)2?2 LiCl as a base in the presence of excess ZnCl2, thus avoiding the typical decarboxylation pathway of these substrates. Direct access to 2-enoic acids allows derivatization by numerous approaches.
MANUFACTURING METHOD OF α,β-UNSATURATED CARBOXYLIC ACID
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Paragraph 0050-0052, (2018/10/16)
PROBLEM TO BE SOLVED: To provide a manufacturing method which can get α,β-unsaturated carboxylic acid at a high yield by liquid phase oxidation of α,β-unsaturated aldehyde by oxygen or air with a handy metal catalyst under a mild reaction condition. SOLUTION: Preferably under a presence of organic solvent, α,β-unsaturated carboxylic acid is manufactured by oxidation of α,β-unsaturated aldehydes and oxygen or air under a presence of an iron salt catalyst and a catalyst of alkali metal salt of carboxylic acid. SELECTED DRAWING: None COPYRIGHT: (C)2017,JPOandINPIT
