- A Visible-Light-Driven Iminyl Radical-Mediated C?C Single Bond Cleavage/Radical Addition Cascade of Oxime Esters
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A room-temperature, visible-light-driven N-centered iminyl radical-mediated and redox-neutral C?C single bond cleavage/radical addition cascade reaction of oxime esters and unsaturated systems has been accomplished. The strategy tolerates a wide range of O-acyl oximes and unsaturated systems, such as alkenes, silyl enol ethers, alkynes, and isonitrile, enabling highly selective formation of various chemical bonds. This method thus provides an efficient approach to various diversely substituted cyano-containing alkenes, ketones, carbocycles, and heterocycles.
- Yu, Xiao-Ye,Chen, Jia-Rong,Wang, Peng-Zi,Yang, Meng-Nan,Liang, Dong,Xiao, Wen-Jing
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supporting information
p. 738 - 743
(2017/12/26)
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- Copper-catalyzed synthesis of thiazol-2-yl ethers from oxime acetates and xanthates under redox-neutral conditions
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A novel copper-catalyzed annulation of oxime acetates and xanthates for the synthesis of thiazol-2-yl ethers with remarkable regioselectivity has been developed. Various oxime acetates, whether derived from aryl ketones or alkyl ketones, or natural product cores are suitable for this conversion. Unique dihydrothiazoles were also obtained when both reaction sites were methine. Mechanistic studies indicated that imino copper(iii) intermediates were involved. In addition, this protocol proceeded under redox-neutral conditions and did not require additives or ligands.
- Zhu, Zhongzhi,Tang, Xiaodong,Cen, Jinghe,Li, Jianxiao,Wu, Wanqing,Jiang, Huanfeng
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supporting information
p. 3767 - 3770
(2018/04/17)
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- IMPROVED METHOD FOR PRODUCING SPECIFIC OXIMES AND OXIMETHERS
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Method for preparing certain oximes and oxime O-methyl ethers by reacting poorly water-soluble carbonyl compounds with salts of hydroxylamine or hydroxylamine O-methyl ether or the free base of hydroxylamine in the presence of certain phosphoric esters or salts thereof of the formula (I) wherein R1, R2 and X are defined as specified in the description.
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Paragraph 0070; 0093-0096
(2016/05/11)
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- Kinetic studies on the reactions of O-(2′,4′-dinitrophenyl) 1,7,7-trimethylbicyclo[2.2.1]heptan-2-one oxime with nucleophiles in aprotic solvents - Mechanism for the uncatalysed pathway
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Kinetics of the reactions of the title compound with some amines as nucleophiles in aprotic solvents have been investigated at the λmax of the aminolysis product at 35 ± 0.1 °C under pseudo-first order conditions. The reaction is overall second order, first with respect to each reactant. The second order rate coefficients decreased with increase in [amine] in all cases. Formation of an electron donor-acceptor complex is indicated. The temperature effect on the reaction rate has been studied in the range (293-318 K). The entropy of activation parameters are large and negative in all cases indicating formation of a crowded transition state. Mechanistic interpretation is given.
- Bhattacharjee,Singh,Gupta, Anshu
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p. 365 - 369
(2008/09/16)
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- N-tert-Butyl-N-chlorocyanamide: A new reagent for the efficient preparation of gem-chloronitroso compounds
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A new reagent for the efficient preparation of gem-chloronitroso compounds has been developed. The reaction of ketoximes with N-tert-butyl-N- chlorocyanamide takes place instantaneously in carbon tetrachloride at room temperature with excellent yields under mild conditions.
- Kumar, Vinod,Kaushik
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p. 8121 - 8123
(2007/10/03)
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- Studies on the preparation of camphorylidene derivatives of α-amino acids
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An improved method has been developed for the efficient synthesis of stable camphor imine salts. Camphor imine readily undergoes transimination with α-amino acid ester hydrochlorides to yield camphorylidene amino acid derivatives with E stereochemistry about the C=N double bond. Sodium cyanoborohydride reduction of the derived ketimines gives exo-bornylamines.
- Gamble, David L.,Hems, William P.,Ridge, Brian
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p. 248 - 260
(2007/10/03)
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- Mono-deoxygenation of nitroalkanes, nitrones, and heterocyclic N-oxides by hexamethyldisilane through 1,2-elimination: Concept of 'counterattack reagent'
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Transformation of secondary nitroalkanes to ketoximes was achieved in 40-73% yields by treatment of the corresponding nitronate anions with hexamethyldisilane. In this new mono-deoxygenation process, hexamethyldisilane acted as a 'counterattack reagent'. The conversion of nitrones to imines was also achieved in 82-88% yields by use of trimethylsilyllithium. Similarly, heterocyclic N-oxides were converted to the corresponding N-heterocycles in 73-86% yields. These deoxygenation processes presumably involve a 1,2-elimination.
- Hwu, Jih Ru,Tseng, Wen Nan,Patel, Himatkumar V.,Wong, Fong Fuh,Horng, Den-Nan,Liaw, Ben Ruey,Lung Ching, Lin
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p. 2211 - 2218
(2007/10/03)
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- Effect of nucleophile on the kinetics of the reaction of N-(2,4-dinitrophenyl)-camphor oxime with cyclohexylamine and piperidine
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Kinetics of aminolysis of N-(2,4-dinitrophenyl)-camphor oxime has been carried out with cyclohexylamine (CHA) and piperidine (PIP) in 1:4 aqueous-acetonitrile (v/v) at 35 +/- 0.1deg C.N-(2,4-dinitrophenyl) piperidine and N-(2,4-dinitrophenyl) cyclohexylamine have been obtained in quantitative yield.Evidence for base catalysis has been obtained in the case of piperidine.Mechanistic interpretation is given.
- Bhattacharjee, Gurudas,Singh, Ashok Kumar,Gairola, Priti
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p. 129 - 132
(2007/10/02)
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- Structure/Odour Relationships of Bicyclic Oximes
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Bicycloheptan-2-one Derivatives, Bridge Homologated Norbornanes, Cassis Odour, Geminal Dimethyl Group Numerous bicyclic oximes are synthesized and for the first time the influence not only of the bicyclic nucleus but also of the α-geminal dimethyl group on the odourous character studied.The pleasant cassis odour of camphenilonoxime seems remarkable.
- Buchbauer, Gerhard,Spreitzer, Helmut,Kotlan, Ulla
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p. 1272 - 1274
(2007/10/02)
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- COUNTERATTACK REAGENTS: THIOSILANES IN THE CONVERSION OF NITRO COMPOUNDS TO THIOHYDROXAMIC ACIDS AND THIOHYDROXIMATES
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Various primary nitro compounds were reacted sequentially with KH and Me3SiSSiMe3 in THF to give thiohydroxamic acids in 56-92 percent yields.By the same strategy, a thiohydroxamic acid was obtained in 50 percent yield by treatment of trans-β-nitrostyrene with i-PrSLi in THF and then with Me3SiSSiMe3.Reaction of primary nitro compounds with n-BuLi and then with MeSSiMe3 or PhSSiMe3 produced the corresponding thiohydroximates in 61-78 percent yields.Secondary nitro compounds were converted to oximes in 68-96 percent yields by reaction with KH and Me3SiSSiMe3 or MeSSiMe3 in THF or 1,4-dioxane.In these "one-flask" reactions, thiosilanes Me3SiSSiMe3, MeSSiMe3, and PhSSiMe3 acted as "counterattack reagents".
- Hwu, Jih Ru,Tsay, Shwu-Chen
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p. 7413 - 7428
(2007/10/02)
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- LIQUID CHROMATOGRAPHIC RESOLUTION OF RACEMIC KETONES AS THEIR OXIME 3,5-DINITROPHENYL CARBAMATES ON A CHIRAL STATIONARY PHASE
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Cyclic and acyclic chiral ketones have been resolved as their oxime 3,5-dinitrophenyl carbamates on a chiral stationary phase derived from (S)-1-(6,7-dimethyl-1-naphthyl)isobutylamine.
- Hyun, Myung Ho,Park, Young -Whan,Baik, In-Kyu
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p. 4735 - 4738
(2007/10/02)
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- Novel Intramolecular Photorearrangement of Nitronate Anions
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The photochemistry of alkanenitronate anions is described.Irradiation of the alkanenitronate anions leads to hydroxamic acids by oxygen photorearrangement via ?-?* triplet excited states.The stoichiometry of reaction, anion structure and selectivity of migration, the nature of the excited state, the quantum yield of reaction, rehybridization on excitation, and the base dependency are discussed.From the results of a detailed structural study of 19 products it was found that this photorearrangement is a highly regio- and stereospecific reaction.
- Yamada, Kazutoshi,Tanaka, Seiji,Naruchi, Kiyoshi,Yamamoto, Makoto
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p. 5283 - 5289
(2007/10/02)
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- Stereochemical Assignment of Camphoroxime by PMR Spectroscopy Using Tris(dipivalomethanato)europium(III)
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Stereochemistry of camphoroxime has been deciphered with the help of PMR spectroscopy using tris(dipivalomethanato)europium (III) as a shift reagent.The hydroxyl group in the oxime has been shown to be syn to γ-methyl on the basis of its anisotropic effect as well as the pronounced paramagnetic induced shift of the γ-methyl.Three methyl (α-, β- and γ-) resonances have also been rationalised using various concentrations of the shift reagent.
- Singh, Ashok Kumar,Verma, Shiva Mohan
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