- Practical bromination of arylhydroxylamines with SOBr2 towards ortho-bromo-anilides
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A facile approach for synthesizing ortho-bromoanilides from readily available aryhydroxylamines and thionyl bromide is demonstrated in this work. Mild reaction conditions and broad scope of substrates ranging from heterocyclic structures to pharmaceutics-potential motifs are used in the reactions of this paper. Efficient bromination of ortho C–H bonds of the aryhydroxylamines has been achieved. Ortho-bromoanilide products were obtained in good to excellent yields, and model scaled-up reactions of this synthetic approach are shown in this work.
- Du, Yuanbo,Feng, Lei,Gao, Hongyin,Guo, Lirong,Lu, Haifeng,Xi, Zhenguo
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- Interrupted fischer-indole intermediates via oxyarylation of alkenyl boronic acids
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The oxyarylation of alkenyl boronic acids with N-arylbenzhydroxamic acids has been achieved under both copper-mediated and copper-catalyzed conditions to provide access to interrupted Fischer-indole intermediates. This transformation is believed to proceed through a copper-promoted C-O bond forming event followed by a [3,3] rearrangement. The scope of the method is described and mechanistic experiments are discussed.
- Wang, Heng-Yen,Anderson, Laura L.
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p. 3362 - 3365
(2013/07/26)
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- Reaction of aromatic nitroso compounds with chemical models of 'thiamine active aldehyde'
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Aromatic nitroso compounds in the presence of base and 2-(α-hydroxyalkyl)-3,4-dimethylthiazolium trifluoromethanesulfonate and related salts furnish in variable yields O- and N-acyl-aryl hydroxylamines and 3,4-dimethylthiazolium trifluoromethanesulfonate. A primary kinetic isotope effect of 4.9, obtained for the appropriate 2α-deuterated thiazolium salt, points to the C2α-H bond cleavage as the rate determining step. Radical species detected by ESR were unambiguously identified as phenylhydronitroxide, but attempted trapping of the corresponding C-heterocyclic radicals by TEMPO was not successful, and substrates incorporating a potential cyclopropyl radical clock gave products with the cyclopropyl ring intact. Theoretical calculations revealed a large activation energy for such reaction, which thus cannot per se exclude the intervention of such radical species. Evidence for the likely operation of two concurrent mechanisms, a radical and a preponderant ionic pathway, involving the conjugate base of the thiazolium salt, as the chemical model for 'active thiamine', and ArNO is presented for the formation of the products of the reaction.
- Ferreira, Luísa M.,Marques, M. Manuel B.,Glória, Paulo M.C.,Chaves, Humberto T.,Franco, Jo?o-Pedro P.,Mourato, Isabel,Antunes, José-Rafael T.,Rzepa, Henry S.,Lobo, Ana M.,Prabhakar, Sundaresan
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p. 7759 - 7770
(2008/12/21)
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- An unusual case of carbon-nitrogen bond formation. Reactivity of a C-nitroso group toward acyl chlorides
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Acyl chlorides react with nitrosobenzene in 99.9% acetonitrile and in the presence of catalytic amounts of HCl giving the corresponding N-p-chlorophenylhydroxamic acids. The spectroscopic and kinetic evidence obtained indicates that the reaction is initia
- Pilepi?, Viktor,Lovrek, Monika,Viki?-Topi?, Dra?en,Ur?i?, Stanko
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p. 8519 - 8522
(2007/10/03)
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- Preparation and Properties of N-Methyl- and N-(4-Chlorophenyl)-Substituted Hydroxamic Acids
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The preparation and properties of several new N-methyl- and N-(4-chlorophenyl)-substituted hydroxamic acids are described.The proton magnetic resonance and mass spectra of a typical N-methyl-substituted hydroxamic acid have also been recorded for characte
- Choudhary, Tilak R.,Tandon, Shiv G.
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p. 237 - 239
(2007/10/02)
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