- N-Methylation of poorly nucleophilic aromatic amines with dimethyl carbonate
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Abstract: Dimethyl carbonate (DMC), an environmentally friendly methylation agent, is a substitute for traditional methylation agents such as methyl halides (CH3X, X?=?I, Br, Cl) or dimethyl sulfate. An efficient, convenient, and green method has been developed for N-methylation of poorly nucleophilic aromatic amines with DMC. It was found that the couple PEG400/K2CO3 provides good selectivity for the N-methylation product. Finally, the mechanism for reaction of amines with DMC was investigated, and a plausible multistep mechanism proposed and verified. Graphical Abstract: [Figure not available: see fulltext.]
- Yan, Huidong,Zeng, Liufang,Xie, Yaqiang,Cui, Yu,Ye, Liyi,Tu, Song
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p. 5951 - 5960
(2016/06/01)
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- The first intramolecular Heck-Matsuda reaction and its application in the syntheses of benzofurans and indoles
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In this Letter, we report, for the first time, the development of an efficient method for the intramolecular Heck reaction of arenediazonium salts in the synthesis of benzofuran and indole derivatives. In addition, this methodology allowed the synthesis of a series of dihydrobenzofuran acetic acid derivatives via a domino Heck-Matsuda coupling-carbonylation reaction.
- Siqueira, Fernanda A.,Taylor, Jason G.,Correia, Carlos Roque D.
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supporting information; experimental part
p. 2102 - 2105
(2010/06/14)
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- Microwave-assisted reductive cyclization of N-allyl 2-nitroanilines: A new approach to substituted 1,2,3,4-tetrahydroquinoxalines
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N-Allyl 2-nitrophenyl amines can be efficiently cyclized to yield alkenyl-1,2,3,4-tetrahydroquinoxalines in a single reaction step by means of a new microwave-assisted reductive domino process. Georg Thieme Verlag Stuttgart.
- Merisor, Elena,Conrad, Jürgen,Mika, Sabine,Beifuss, Uwe
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p. 2033 - 2036
(2008/02/09)
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- Flow cell electrosynthesis of o-substituted nitrosobenzenes. In situ reaction with sulfinic acids. Attempt to prepare heterocycles.
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Nitrosobenzenes with CO2H 1b, CO2CH3 2b, CONR2 3b-6b, CH2CO2H 7b, CHOHCO2H 8b and NHCO2CH3 9b ortho-substituted were prepared, in a "redox" cell, from the corresponding nitro compounds.Addition of sulfinic acids to the solution after electrolyses leads to
- Guilbaud-Criqui, A.,Moinet, C.
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p. 295 - 300
(2007/10/02)
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- Basic Hydrolysis of Some N-Phenylcarbamates and Basic Methanolysis of Some N-Phenylacetamides Containing an ortho Nitro Substituent.
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Kinetic studies of the basic methanolysis of N-(2-nitrophenyl)acetamides indicate that unlike the 4-nitro isomer, no change of mechanism occurs on inclusion of N-methyl group.Reaction occurs with rate-determining C-N bond breaking for both the N-H and N-methyl compounds.Basic hydrolysis of some methyl N-(2-nitrophenyl)carbamates occurred by the BAC2 mechanism and the tetrahedral intermediate formed during the hydrolysis decomposed with preferential C-O bond breaking.This is in contrast to the basic hydrolysis of methyl N-methyl-N-4-nitrophenylcarbamate, which has previously been shown to occur with preferential C-N bond breaking.For the hydrolysis of methyl N-methyl-N-(2-nitrophenyl)carbamate, an induction period in amine production was detected at 0.45 M hydroxide ion.This was interpreted to mean that the tetrahedral intermediate breaks down by loss of methoxide ion.At 0.93 M hydroxide ion, however, no induction period in amine production was observed.The possibility of reaction through a dianionic intermediate was raised to explain this observation.The amide ion (2-NO2C6H4NMe-) is poorer leaving group than its 4-nitro isomer thi is explained by steric crowding in the 2-nitro compound, resulting in twisting of the nitro group out of the plane of the benzene ring and a consequent reduction in the electron-withdrawing resonance effect of the 2-nitro group compared to the 4-nitro gruop.
- Broxton, Trevor J.
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p. 2005 - 2011
(2007/10/02)
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