1191-04-4Relevant articles and documents
Synthesis of Carboxylic Acid by 2-hexenal oxidation using gold catalysts Supported on MnO2
Alshammari, Hamed
, (2016)
Synthesis of carboxylic acid can be achieved by the oxidation of aldehyde using air as an oxidant in the presence of a potential catalyst. We demonstrated that 2-hexenal can be oxidized to carboxylic acid by Au, Pd, and Au-Pd catalysts and investigated the effects of catalyst support (graphite, TiO2, MgO, SiC, MnO2, CeO2, and Al2O3), preparation method for supported catalyst (sol immobilization, impregnation, and deposition precipitation), and choice of catalyst components. Analysis of conversion% and selectivity% for 2-hexenoic acid showed that MnO2-supported gold nanoparticles are the best catalysts for 2-hexenal oxidation. Moreover, catalysts prepared by sol immobilization are the most active possibly due to the much smaller gold nanoparticle size. Selectivity for 2-hexenoic acid is a major pathway of oxidation of 2-hexenal.
NHC-catalysed highly selective aerobic oxidation of nonactivated aldehydes
Moehlmann, Lennart,Ludwig, Stefan,Blechert, Siegfried
, p. 602 - 607 (2013)
This publication describes a highly selective oxidation of aldehydes to the corresponding acids or esters. The reaction proceeds under metal-free conditions by using N-heterocyclic carbenes as organocatalysts in combination with environmentally friendly oxygen as the terminal oxidation agent.
Catalytic hydrogenation of sorbic acid using pyrazolyl palladium(II) and nickel(II) complexes as precatalysts
Darkwa, James,Kumar, Gopendra,Makhubela, Banothile C. E.,Muyaneza, Apollinaire,Olaoye, Oluwasegun E.,Oyetunji, Olayinka
, p. 50 - 56 (2021/12/09)
We have prepared several pyrazolyl palladium and nickel complexes ([(L1)PdCl2] (1), [(L2) PdCl2] (2), [(L3) PdCl2] (3), [(L1) NiBr2] (4), [(L2) NiBr2] (5) and [(L3) NiBr2] (6)) by reacting 3,5-dimethyl-1H-pyrazole (L1), 3,5-di-tert-butyl-1H-pyrazole (L2) and 5-ferrocenyl-1H-pyrazole(L3) with [PdCl2(NCMe)2] or [NiBr2(DME)] to afford mononuclear palladium and nickel complexes, respectively. These complexes were then investigated as pre-catalysts in the hydrogenation of 2,4-hexadienoic acid (sorbic acid). The active catalysts from these complexes demonstrate significant activities under mild experimental conditions. Additionally, the active catalysts show that the hydrogenation of sorbic acid proceeds in a sequential manner, where the less hindered C=C bond (4-hexenoic acid) is preferentially reduced over the more hindered C=C bond (2-hexenoic acid).
Direct Enantioselective and Regioselective Alkylation of β,γ-Unsaturated Carboxylic Acids with Chiral Lithium Amides as Traceless Auxiliaries
Yu, Kai,Miao, Bukeyan,Wang, Wenqi,Zakarian, Armen
supporting information, (2019/03/19)
Efficient asymmetric alkylation of β,γ-unsaturated carboxylic acids without prior functionalization is enabled by chiral lithium amides. Enantioselectivity is imparted by a putative mixed lithium amide-enediolate aggregate that acts a traceless auxiliary formed in situ, allowing for a direct asymmetric alkylation and a simple recovery of the chiral reagent.
A biocatalytic method for the chemoselective aerobic oxidation of aldehydes to carboxylic acids
Knaus, Tanja,Tseliou, Vasilis,Humphreys, Luke D.,Scrutton, Nigel S.,Mutti, Francesco G.
supporting information, p. 3931 - 3943 (2018/09/11)
Herein, we present a study on the oxidation of aldehydes to carboxylic acids using three recombinant aldehyde dehydrogenases (ALDHs). The ALDHs were used in purified form with a nicotinamide oxidase (NOx), which recycles the catalytic NAD+ at the expense of dioxygen (air at atmospheric pressure). The reaction was studied also with lyophilised whole cell as well as resting cell biocatalysts for more convenient practical application. The optimised biocatalytic oxidation runs in phosphate buffer at pH 8.5 and at 40 °C. From a set of sixty-one aliphatic, aryl-Aliphatic, benzylic, hetero-Aromatic and bicyclic aldehydes, fifty were converted with elevated yield (up to >99%). The exceptions were a few ortho-substituted benzaldehydes, bicyclic heteroaromatic aldehydes and 2-phenylpropanal. In all cases, the expected carboxylic acid was shown to be the only product (>99% chemoselectivity). Other oxidisable functionalities within the same molecule (e.g. hydroxyl, alkene, and heteroaromatic nitrogen or sulphur atoms) remained untouched. The reaction was scaled for the oxidation of 5-(hydroxymethyl)furfural (2 g), a bio-based starting material, to afford 5-(hydroxymethyl)furoic acid in 61% isolated yield. The new biocatalytic method avoids the use of toxic or unsafe oxidants, strong acids or bases, or undesired solvents. It shows applicability across a wide range of substrates, and retains perfect chemoselectivity. Alternative oxidisable groups were not converted, and other classical side-reactions (e.g. halogenation of unsaturated functionalities, Dakin-Type oxidation) did not occur. In comparison to other established enzymatic methods such as the use of oxidases (where the concomitant oxidation of alcohols and aldehydes is common), ALDHs offer greatly improved selectivity.
Enantioselective Synthesis of N?H-Free 1,5-Benzothiazepines
Wang, Guojin,Tang, Yu,Zhang, Yu,Liu, Xiaohua,Lin, Lili,Feng, Xiaoming
supporting information, p. 554 - 557 (2017/01/18)
An enantioselective sulfa-Michael-cyclization reaction was developed for the synthesis of 1,5-benzothiazepines with versatile pharmacological activities. The reaction between 2-aminothiophenol and α,β-unsaturated pyrazoleamides gave direct access to N?H-free 1,5-benzothiazepines in the presence of a chiral N,N′-dioxide/Yb(OTf)3complex. Excellent enantioselectivities (up to 96 % ee) and high yields (up to 99 %) were obtained for a broad range of substrates under mild reaction conditions. This method provided a facile approach to the antidepressant drug (R)-(?)-Thiazesim.
Industrialization preparing method for 3-propyl-ethylene oxide-2-carbonyl cyclopropanecarboxamide
-
Paragraph 0019; 0020, (2017/04/29)
The invention discloses an industrialization preparing method for 3-propyl-ethylene oxide-2-carbonyl cyclopropanecarboxamide, and belongs to the field of pharmaceutical chemistry. The industrialization preparing method includes the steps that malonic acid serves as a initial raw material, malonic acid (A) is added into alkali, and then the mixture and butyric aldehyde (B) are condensed to prepare hexenic acid (C); an acylation reagent is added into the hexenic acid (C), an acylation reaction is carried out, then concentration is carried out, and hexenoyl chlorine (D) is obtained; the hexenoyl chlorine (D) and cyclopropylamine are reacted to obtain hexenoyl amine (E), the exenoyl amine (E) is subjected to an epoxidation reaction, and the 3-propyl-ethylene oxide-2-carbonyl cyclopropanecarboxamide is obtained. According to the industrialization preparing method, the malonic acid is used as a raw material; compared with the traditional technology, the materials are easy to obtain, the cost is only about 20% of the cost of 'a first path', the cost is greatly reduced, the yield is higher, is 90% or above, and is increased by 15% or above compared with the yield of 'the first path' and increased by 30% or above compared with the yield of 'a second path', the reaction condition is more mild, operating is more convenient, and the requirements of mass industrialization production can be met.
Enzyme cascade reactions: Synthesis of furandicarboxylic acid (FDCA) and carboxylic acids using oxidases in tandem
McKenna, Shane M.,Leimkühler, Silke,Herter, Susanne,Turner, Nicholas J.,Carnell, Andrew J.
supporting information, p. 3271 - 3275 (2015/06/25)
A one-pot tandem enzyme reaction using galactose oxidase M3-5 and aldehyde oxidase PaoABC was used to convert hydroxymethylfurfural (HMF) to the pure bioplastics precursor FDCA in 74% isolated yield. A range of alcohols was also converted to carboxylic acids in high yield under mild conditions.
On the role of CO2 in NHC-catalyzed oxidation of aldehydes
Chiang, Pei-Chen,Bode, Jeffrey W.
supporting information; experimental part, p. 2422 - 2425 (2011/06/23)
Chemical equations presented. NHC-catalyzed oxidations using carbon dioxide as the stoichiometric oxidant have been carefully investigated. These studies support a secondary role of CO2 in suppressing side reactions and exogenous oxygen as the actual oxidant.
On C-As bond formation: Preparation of aliphatic arsonic acids
Ioannou, Panayiotis V.
, p. 1 - 14 (2007/10/03)
A review of the attempts to create a C-As bond in aliphatic arsonic acids using a variety of As(III) nucleophiles and carbon electrophiles is presented together with our additional efforts on this subject. The results suggest that the Meyer reaction canno
