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1.
Using novel nitrite-containing resin as an NO source and Amberlyst-15 as cocatalyst, we developed aerobic oxidation of oximes to corresponding carbonyl compounds with molecular oxygen as a clean oxidant reagent. It was distinguished from the previous related reports, and the experimental results indicated that additional water obviously decreased the yield. This process provides a better choice for oxidative deoximation with many advantages, such as high yield, simple procedure, high catalytic performance, and recyclable catalyst. 相似文献
2.
An acceptor‐free catalysis protocol for the deoximation of ketoximes and aldoximes using RuCl3 as the catalyst has been developed. Under the optimized conditions, various oximes were converted to ketones and nitriles with excellent isolated yields. 相似文献
3.
《合成通讯》2013,43(10):1607-1612
A simple convenient procedure of oxidative deoximation has been developed using pyridinium fluorochromate (PFC), in combination with 30% hydrogen peroxide. The method has been found to be effective for a wide range of aliphatic and aromatic oximes, and may be used for selective cleavage of aldoximes in the presence of ketoximes. 相似文献
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Deoximation in metal chloride ionic liquids based on 1‐alkyl‐3‐methylimidazolium and triethylene ammonium cations, such as AmimBr(Cl)‐MClx(A=ethyl, butyl, benzyl; M=Al, Fe, Cu, Sn and Zn; x=2, 3) and Et3NHCl‐FeCl3 were investigated under mild conditions. Ferrate chloride ionic liquid was proved to be an effective catalyst for deoximation of cyclohexanone oxime, exhibiting high conversion of oximes and selectivity to cyclohexanone. Good performance for the deoximation of other oximes such as salicylald oxime, acetone oxime, benzophenone oxime, 4‐nitrobenzald oxime, acetophenone oxime, 2‐chlorobenzaldehyde oxime, Acetald oxime, 2‐butanone oxime and (1R)‐camphor oxime was also achieved with bmimBr‐FeCl3 as catalyst and solvent. The deoximation was determined to carry out via acid‐catalytic hydrolysis and the reaction mechanism was proposed. 相似文献
6.
Aldeydes and ketones are easily obtained in high yields by microwave promoted rapid oxidative deoximation of the corresponding oximes with zinc nitrate hexahydrate adsorbed on silica gel under solvent free conditions. 相似文献
7.
Alexander O. Terent’ev Igor B. Krylov Vera A. Vil’ Zhanna Yu. Pastukhova Sergey A. Fastov Gennady I. Nikishin 《Central European Journal of Chemistry》2012,10(2):360-367
It was found that oximes undergo deoximation in the presence of the H2O2aq-HBraq system to form ketones and bromo ketones. This reaction provided the basis for the synthesis of dibromo ketones in yields
varying from 40% to 94%. This method is environmentally friendly, sustainable, and easy to perform. The results of this investigation
extend the potential of the use of oximes for the protection of carbonyl group, thus offering the ability to perform not only
conventional deoximation but also the subsequent bromination of ketones. The reaction is easily scaled up and dibromo ketones
can be prepared in gram amounts.
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8.
Recent advances on the deoximation reactions are reviewed in this review. It was shown that catalytic deoximation with molecular oxygen as the mild oxidant should be the developing trend of the reaction. 相似文献
9.
The organic chemistry of polyvalent iodine compounds has experienced an unprecedented development during the last decade of 20th century.[1,2] On the other hand, despite its extensive use in industry, I2O5 (iodine pentoxide, IP) has rarely been employed in organic synthesis except as an alternative to iodoxybenzoic acid (IBX) for the dehydrogenation of aldehydes and ketones.[3] Generally, pentavalent iodine reagents, such as IBX and Dess-Martin periodinane (DMP)were used as mild and selective oxidants for oxidation of alcohols[1,2] and dehydrogenation of carbonyl compounds.[3] We wish to report herein that IP can serve as a mild and efficient reagent for the oxidative cleavage of oximes to aldehydes and ketones (Eq. 1). Most interestingly, IP can also activate hydrosilanes for reduction of alkenes. Hence, simultaneous deoximation and conjugate reduction of α,β-unsaturated ketoximes can be achieved by using IP and phenyldimethylsilane (Eq. 2). 相似文献
10.
研究了10种取代苯甲醛肟和5种取代苯乙酮肟的电化学氧化机理。这二类肟的氧化电位随取代基吸电子能力的增大而增高,并与它们相应的Hammett常数有线性关系。它们在电化学氧化过程中均有iminoxy自由基生成,但最后产物各不相同。用控制电位电解和紫外吸收光谱检法验证了部分电化学氧化产物。因此,电化学氧化法可作为由肟类产生iminoxy自由基的一种方法。 相似文献
11.
研究了7种取代查耳酮肟的电化学行为。用氢氧化钠底液热解石墨工作电极,取代查耳酮肟的电极过程为1e氧化不可逆吸附电极过程。它们的氧化电位随取代基吸电子能力的增强而增高,并与它们相应的Hammett常数呈线性关系。取代查耳酮肟的电化学氧化机理为先失去一个电子生成iminoxy自由基,然后由基对分子内烯键进行环化加成,脱氢后形成3,5-二聚代异恶唑。用控电位电解和紫外吸收光谱检测了部份电化学氧化产物,证 相似文献
12.
Chunhong Wang Qi Cui Zhixin Zhang Prof. Zhu-Jun Yao Dr. Shaozhong Wang Prof. Zhi-Xiang Yu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(42):9821-9826
1,3-Azaprotio transfer of propargylic α-ketocarboxylate oximes, a new type of alkynyl oximes featuring an ester tether, has been explored by taking advantage of gold catalysis. The incorporation of an oxygen atom to the chain of alkynyl oximes led to the formation of two different oxa-cyclic nitrones. It was found that internal alkynyl oximes with an E-configuration deliver five-membered nitrones, whereas terminal alkynyl oximes with an E-configuration afford six-membered nitrones. DFT calculations on four possible pathways supported a stepwise formation of C−N and C−H bonds, in which a 1,3-acyloxy-migration competes with the 1,3-azaprotio-transfer, especially in the case of internal alkynyl oximes. The relative nucleophilic properties of oxygen in the carbonyl group and the nitrogen in the oxime, the electronic effects of alkynes, and the influence of the ring system have been investigated computationally. 相似文献
13.
Oximes, O-benzoyloximes and sodium salt of aldoximes and ketoximes were deoximated to their parent carbonyl compounds with copper (II) chloride dihydrate in acetonitrile as well as water. This method works well with both aldoximes and ketoximes without any risk of overoxidation in the former case. In addition, sensitive groups like ester, acetamido, isolated as well as conjugated carbon-carbon double bond and phenolic and ether linkages could survive the reaction conditions. The yields and reaction rates were increased in case of aromatic oximes when the reaction was carried out in aqueous acetonitrile. A novel deoximation procedure using sodium oximate which showed considerable rate enhancement over that of oximes, and tolerance to hydrolytically labile ester and amide groups is also described. 相似文献
14.
The deoximation kinetics of some oximes was studied by using cetyltrimethylammonium dichromate (CTADC) in dichloromethane in the presence of acetic acid and a cationic surfactant. The rate of reaction is highly sensitive to the change in [CTADC], [oxime], [acid], [surfactant], polarity of the solvents, and reaction temperature. The reaction is found to be catalyzed by acid with an appreciable uncatalytic rate. The reaction is first order with respect to substrate. With increase in CTADC concentration, rate of the reaction increases with a fractional order dependency with respect to oxidant. Consistent to the observation, a mechanism has been proposed in which the substrate forms a complex with CTADC in the rate determining step followed by decomposition with a fast process to yield corresponding carbonyl compounds. The structure of the substituents has also a significant effect on the rate constant. © 2011 Wiley Periodicals, Inc. Int J Chem Kinet 43: 482–488, 2011 相似文献
15.
Sandeep Bhosale 《Tetrahedron》2010,66(50):9582-9588
Magtrieve™ (CrO2) and MnO2 mediated oxidation of aldoximes to nitrile oxides were studied in details. In presence of external radical source, TEMPO, these reagents did not furnish nitrile oxides, instead favoured deoximation to aldehydes. A common trend of deoximation was established from electronically tuned aldoximes, which is: aliphatic>aromatic>aldoximes with strong electron-withdrawing group, though the extent of deoximation was less in case of CrO2. Above effects were not observed with chloramine-T and diacetoxyiodobenzene, reagents known to produce nitrile oxides via hydroximoyl halide or equivalent ionic intermediates. A putative reaction mechanism is proposed for MO2 (M=Cr, Mn) mediated oxidation of aldoximes through formation of a nitroso-oxime tautomeric pair. Formation of nitrile oxide is possibly occurred from the oxime tautomer via a σ-type iminoxy radical intermediate. The deoximation process, dominating in presence of external radical environment, is explained following decomposition of the nitroso tautomer. 相似文献
16.
Novakov I. A. Nawrozkij M. B. Mkrtchyan A. S. Voloboev S. N. Vostrikova O. V. Vernigora A. A. Brunilin R.V. 《Russian Journal of Organic Chemistry》2019,55(11):1742-1748
The reduction of cage ketoximes under Schwenk–Papa reaction conditions was studied to establish that the d,l, d- and l-camphor oximes are smoothly reduced to the corresponding amines in high yields. At the same time, d,l-norcamphor and adamantan-2-one oximes undergo partial catalytic deoximation to form a mixture of the corresponding amines and alcohols.
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A mild, simple process for the effective deoximation of a wide range of ketoximes and aldoximes has been developed, which utilizes available NaNO(2) as the catalyst and molecular oxygen as the green oxidant. Notably Amberlyst-15, which acts as the initiator of NaNO(2), can be reused without regeneration. This environmentally benign protocol could provide a valuable synthetic method for practical applications. 相似文献
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20.
Pradeep K. Sharma 《国际化学动力学杂志》2006,38(6):364-368
The oxidative deoximination of several aldo‐ and keto‐oximes by pyridinium bromochromate (PBC), in dimethylsulfoxide, exhibited a first‐order dependence on both the reductant (oxime) and the oxidant (PBC). The oxidation of ketoximes is slower than that of aldoximes. The rates of oxidation of aldoximes correlated well in terms of the Pavelich–Taft dual substituent‐parameter equation. The low positive value of polar reaction constant indicated a nucleophilic attack by a chromate‐oxygen on the carbon. The reaction is subject to steric hindrance by the alkyl groups. The reaction of acetaldoxime has been studied in 19 different organic solvents. The solvent effect has been analyzed by Taft's and Swain's multiparametric equations. A mechanism involving the formation of a cyclic intermediate, in the rate‐determining step, has been proposed. © 2006 Wiley Periodicals, Inc. Int J Chem Kinet 38: 364–368, 2006 相似文献