- Copper(0)/PPh3-Mediated Bisheteroannulations of o-Nitroalkynes with Methylketoximes Accessing Pyrazo-Fused Pseudoindoxyls
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A copper(0)/PPh3-mediated cascade bisheteroannulation reaction of o-nitroalkynes with methylketoximes has been developed that provides viable access to a diverse range of pyrazo-fused pseudoindoxyl compounds. Synthetically useful functional groups including sensitive C-I bonds are compatible with this system. Mechanistic studies suggest a reaction cascade involving sequential PPh3-mediated deoxygenative cycloisomerization and copper-catalyzed [3 + 2] pyrazo-annulation.
- Meng, Huanxin,Xu, Zhenhua,Qu, Zhonghua,Huang, Huawen,Deng, Guo-Jun
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supporting information
p. 6117 - 6121
(2020/08/12)
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- Preparation method of pyrimidine salicylate oxime ester compound and application of compound as herbicide
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The invention discloses a preparation method of a pyrimidine salicylate oxime ester compound and application of the compound as a herbicide, belongs to the technical field of herbicides, and relates to the application of the herbicide in selectively controlling gramineous weeds and broadleaf weeds for crops. The compound is a pyrithiobac oxime ester compound. The preparation method includes the following steps that acids of pyrithiobac are condensed with substituted acetophenoxime in the presence of an organic solvent and a condensation agent to prepare a (I) compound. At 45 g a.i./hm, thecompound can effectively control echinochloa crusgalli, eleusineindica, setaria viridis, amaranthus retroflexus, portulaca oleracea, chenopodium album and other grassy weeds and broadleaf weeds, can serve as a candidate herbicide in a cotton field and has potential industrial application. Meanwhile, the compound is environmentally friendly, low in toxicity and highly safe for crops such as cotton.The invention provides a preparation technology of the efficient and safe novel pyrimidine salicylate oxime ester compound with the herbicidal activity, the compound can be massively produced, the yield is high and the purity is high.
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Paragraph 0099; 0100
(2019/10/22)
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- SO2F2-Activated Efficient Beckmann Rearrangement of Ketoximes for Accessing Amides and Lactams
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A novel, mild and practical protocol for the efficient activation of the Beckmann rearrangement utilizing the readily available and economical sulfuryl fluoride (SO2F2 gas) has been developed. The substrate scope of the operationally simple methodology has been demonstrated by 37 examples with good to nearly quantitative isolated yields (over 90 % yield in most cases) in a short time, including B(OH)2, COOH, NH2, and OH substituted substrates. A tentative mechanism was proposed involving formation and elimination of key intermediate, sulfonyl ester.
- Zhang, Guofu,Zhao, Yiyong,Xuan, Lidi,Ding, Chengrong
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supporting information
p. 4911 - 4915
(2019/07/31)
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- Catalyst free synthesis of mono- and disubstituted pyrimidines from O-acyl oximes
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Transition-metal or iodine catalyzed transformations of O-acyl oximes to various N-heterocycles are well established. Herein, we report a catalyst free, oxime carboxylate based, three-component condensation method to access mono- and disubstituted pyrimidines. A broad range of substituted pyrimidines were prepared in moderate to excellent yields. Control experiments reveal that in situ generated formamidine is the key intermediate.
- Upare, Atul,Sathyanarayana, Pochampalli,Kore, Ranjith,Sharma, Komal,Bathula, Surendar Reddy
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supporting information
p. 2430 - 2433
(2018/05/23)
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- TETRAZOLINONE COMPOUND AND USE THEREOF
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The compound represented by formula (1): wherein R4 and R5 each represents a hydrogen atom, a halogen atom, or a C1-C3 alkyl group; R6 represents a C1-C4 alkyl group, a C3-C6 cycloalkyl group, or the like; R7, R8, and R9 each represents a hydrogen atom, a halogen atom, or the like; R10 represents a C1-C3 alkyl group, or the like; R13 represents a C1-C3 alkyl group, or the like; and Q represents a phenyl group, or the like; has an excellent control effect on pests.
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Paragraph 0844-0845
(2015/11/16)
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- Direct oxidative coupling of enamides and 1,3-dicarbonyl compounds: A facile and versatile approach to dihydrofurans, furans, pyrroles, and dicarbonyl enamides
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An efficient manganese(III)-mediated oxidative coupling reaction between α-aryl enamides and 1,3-dicarbonyl compounds has been developed. A series of dihydrofurans and dicarbonyl enamides were synthesized in moderate to good yields. Moreover, these dihydrofurans could be readily transformed into the corresponding furans and pyrroles via the Paal-Knorr reaction.
- Li, Pan,Zhao, Jingjing,Xia, Chungu,Li, Fuwei
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supporting information
p. 5992 - 5995
(2015/01/08)
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- Synthesis of dibromo ketones by the reaction of the environmentally benign H2O2-HBr system with oximes
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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. Versita Sp. z o.o.
- Terentev, Alexander O.,Krylov, Igor B.,Vil, Vera A.,Pastukhova, Zhanna Yu.,Fastov, Sergey A.,Nikishin, Gennady I.
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experimental part
p. 360 - 367
(2012/08/08)
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- Facile and efficient enantioselective strecker reaction of ketimines by chiral sodium phosphate
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A facile and efficient enantioselective Strecker reaction of ketimines catalyzed by a chiral alkali-metal salt has been developed. When 10 mol% BNPNa (BNP=1,1'-binaphthyl-2,2'-diylphosphate) prepared in situ and 10 mol% para-tert-butylortho-adamantylphenol (PBAP) were introduced into the reaction, up to 96% yield and up to 95% ee (ee=enantiomeric excess) were obtained. Both aliphatic and aromatic ketimines, especially sterically bulky cyclic ketimines derived from β-acetonaphthone, α-indanone, and α-tetralone were found suitable for this reaction. On the basis of the experimental results and previous reports, trimethylsilyl cyanide (TMSCN) was indicated to be the real reactive nucleophile despite the existence of PBAP, and a possible working model was proposed to explain the origin of the asymmetric induction. The facile availability of 1,1'-binaphthyl-2,2'-diylphosphoric acid (BNPH) and the simplicity of the procedure are beneficial for practical applications.
- Shen, Ke,Liu, Xiaohua,Cai, Yunfei,Lin, Lili,Feng, Xiaoming
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supporting information; experimental part
p. 6008 - 6014
(2010/02/28)
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- Enantioselective Strecker reaction of phosphinoyl ketoimines catalyzed by in situ prepared chiral N,N′-dioxides
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The enantioselective Strecker reaction of N-diphenylphosphinoyl ketoimines has been achieved by use of in situ prepared chiral N,N′-dioxide catalyst from L-piperidinamide 3f and m-chloroperoxybenzoic acid (m-CPBA). Excellent yields (up to 99%) and high enantioselectivities (up to 92% ee) were obtained. In particular, in situ prepared catalyst with readily available chiral material made the procedure more convenient. Moreover, the L-piperidinamide 3f-derived N,N′-dioxide 9 could be recycled and reused at least five times without any loss of either catalytic activity or enantioselectivity.
- Huang, Jinglun,Liu, Xiaohua,Wen, Yuehong,Qin, Bo,Feng, Xiaoming
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p. 204 - 208
(2007/10/03)
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- Quinone-sensitized steady-state photolysis of acetophenone oximes under aerobic conditions: Kinetics and product studies
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Oxidation of oximes via photosensitized electron transfer (PET) results in the formation of the corresponding ketones as the major product via oxime radical cations and iminoxyl radicals. The influence of electron-releasing and electron-accepting substituents on these reactions was studied. The observed substituent effect strongly supports formation of iminoxyl radicals from the oximes via an electron transfer-proton transfer sequence rather than direct hydrogen atom abstraction. Correlation of the relative conversion of the oximes with Hammett parameters shows that radical effects dominate for the meta-substituted acetophenone oximes (ρrad/ ρpol = 5.4; r2 = 0.93), whereas the para-substituted oximes are influenced almost equally by radical and ionic effects (ρrad/ ρpol = -1.1; r2 = 0.98). From these data sets we conclude that the follow-up reactions proceed through a number of intermediates with both radical and ionic character. This was confirmed by product studies with the use of an isotopically labeled nucleophile. In addition to the major oxidation product (ketone), a chlorine-containing product was often identified as well. Studies on the formation of this product show that the most likely pathway is either via a direct nucleophilic addition in a complex formed between the oxime radical cation and the chloranil radical anion or via a radical substitution (SH2) mechanism. These studies show that with the increasing use of oximes as drugs and pesticides, intake of these chemicals followed by enzymatic oxidation may result in the formation of a variety of reactive intermediates, which may lead to cell and tissue damage.
- Park, Adriana,Kosareff, Nicole M.,Kim, Jason S.,De Lijser, H. J. Peter
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p. 110 - 118
(2008/02/12)
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- Solid-phase synthesis of oximes
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In an extremely fast, high efficient and novel method, the reaction of hydroxylamine hydrochloride with a number of aldehydes and ketones under solventless 'dry' condition gave oximes in quantitative yield.
- Hajipour,Mohammadpoor-Baltork,Nikbaghat,Imanzadeh
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p. 1697 - 1701
(2007/10/03)
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- A High-Yield Regiospecific Synthesis of Keto Oximes from Aryl-Conjugated Ethylenes and Ethyl Nitrite in the Presence of Cobalt Complex and BH4- Ion
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The title reaction of substituted styrenes, 1-phenyl-1,3-butadiene, and some cyclic aryl-conjugated ethylenes proceeds smoothly at room temperature, affording the corresponding oximes in moderate to nearly quantitative yields.The reaction mechanism is discussed on the basis of the formation of an alkylcobalt intermediate and its subsequent reaction with ethyl nitrite.
- Okamoto, Tadashi,Kobayashi, Kenji,Oka, Shinzaburo,Tanimoto, Shigeo
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p. 4897 - 4901
(2007/10/02)
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- Cobalt-Catalyzed Reaction of Nitric Oxide with Aryl-Substituted Olefins in the Presence of Tetrahydroborate Ion
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A new transition-metal-catalyzed reaction of nitric oxide with aryl-substituted olefins in the presence of BH4- has been reported, where the oximes of alkyl aryl ketones are the products.The most successful results were obtained by using styrene and its ring-substituted derivatives as the substrate and Co(DH)2(py)Cl as the catalyst.A process involving the intermediate formation of a metal-alkyl complexes and its subsequent decomposition alkyl radical followed by the reaction of the radical with NO was proposed as the reaction mechanism in relation to the already reported cobalt-catalyzed oxygenation of aryl-substituted olefins.
- Okamoto, Tadashi,Kobayashi, Kenji,Oka, Shinzaburo,Tanimoto, Shigeo
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p. 5089 - 5092
(2007/10/02)
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- REACTION D'OXIMATION DES CETONES V. MECANISME ET EFFETS DE STRUCTURE DANS LA REACTION DE DESHYDRATATION ACIDO-CATALYSEE DES CARBINOLAMINES
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The equilibrium constants of formation and the rate constants of dehydratation of carbinolamines resulting from the addition of hydroxylamine to 19 ketones, - 5 aliphatic, 5 aromatic and 9 cyclanic -, have been measured at 25 deg C in water/methanol 60/40 v/v.We show that the acid catalyzed process predominates in the range of pH 6 to 7 for acetophenones or pH 7 to 8.5 for saturated ketones.The rate constants ratios and Hammett ρ constant of the reaction suggest an sp3 (early) transition state.The changes in rate constant are discussed in terms of torsional and non-bonding steric effects.For several hindered ketones, e.g. 3,3,5,5-tetramethylcyclohexanone, we show the existence of a steric hindrance to the approach of the catalyst; in that case the result is a strong decrease of the rate of the dehydratation.
- Lamaty, G.,Roque, J. P.,Natat, A.,Silou, T.
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p. 2667 - 2676
(2007/10/02)
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