144181-67-9Relevant academic research and scientific papers
Metal-free chemoselective ortho -C(sp2)-F bond hydroxylation and N-trifluoroacylation of fluoroarylamines for domino synthesis of 2-(N-trifluoroacyl)aminophenols
Venkateswarlu, Vunnam,Balgotra, Shilpi,Aravinda Kumar,Vishwakarma, Ram A.,Sawant, Sanghapal D.
supporting information, p. 1258 - 1262 (2015/06/02)
Abstract A novel chemoselective reaction for the formation of C-O bonds by C(sp2)-F bond cleavage and concomitant N-trifluoroacylation of fluoroanilines using trifluoroacetic acid and Oxone is presented. This domino reaction gives o-hydroxy-N-trifluoroacetanilides in good yields under metal-free conditions in a single step. Selective ortho-directed monohydroxylation and N-trifluoroacylation of 2- and 6-fluoro- or 2,6-difluoro-substituted anilines takes place in this transformation.
C-H oxygenation and N-trifluoroacylation of arylamines under metal-free conditions: A convenient approach to 2-aminophenols and N-trifluoroacyl-ortho- aminophenols
Venkateswarlu, Vunnam,Kumar, K. A. Aravinda,Balgotra, Shilpi,Reddy, G. Lakshma,Srinivas,Vishwakarma, Ram A.,Sawant, Sanghapal D.
supporting information, p. 6641 - 6645 (2014/06/09)
Direct ortho-hydroxylation through C-H oxygenation and N-trifluoroacylation of anilines was achieved in a single step under metal-free conditions by using a combination of TFA and oxone. The method allowed the formation of functionalised amino phenolic compounds such as ortho-hydroxy-N- trifluoroacetanilides in good yields with broad substrate scope.
Synthesis of 2-aminophenols and heterocycles by Ru-catalyzed C-H mono- and dihydroxylation
Yang, Xinglin,Shan, Gang,Rao, Yu
supporting information, p. 2334 - 2337 (2013/07/04)
A novel and efficient synthesis of 2-aminophenols, 2-aminobenzene-1,3- diols, and heterocycles through Ru-catalyzed C-H mono- and dihydroxylation of anilides has been developed with a new directing group strategy. The reaction demonstrates excellent reactivity, regioselectivity, good functional group tolerance, and high yields.
Acid-catalyzed amino-migration of O-phenylhydroxylamines
Haga, Naoki,Endo, Yasuyuki,Kataoka, Ken-Ichiro,Yamaguchi, Kentaro,Shudo, Koichi
, p. 9795 - 9806 (2007/10/02)
The mechanism of amino-migration of O-phenylhydroxylamine (1a) was studied. It was found that 1 rearranges to give 2-aminophenol (50%) and 4-aminophenol (7%) in trifluoroacetic acid (TFA). The predominance of the ortho rearrangement of 1 clearly distinguishes this process from the Bamberger rearrangement. From cross-coupling experiments employing stable isotopes, it was clarified that the ortho rearrangement proceeds intramolecularly and the para rearrangement involves both intra- and intermolecular processes. Good first-order kinetics were obtained for the rearrangement. The Hammett plot (σ+) with a large negative slope (ρ = -7.8) indicates that initial heterolytic N-O bond cleavage of 1 occurs and generates a positive charge on the oxygen atom with considerable delocalization into the aromatic ring. An ion-molecule pair involving a phenoxenium ion and an ammonia molecule as an intermediate rationalizes all of the results. In this pair, intramolecular combination to the ortho position proceeds preferentially over that to the para position. Formation of catechol and hydroquinone can be explained in terms of nucleophilic attack of TFA on the phenoxenium ion in a solvent-separated pair.
2-(Trifluoroacetyloxy)pyridine as a Mild Trifluoroacetylating Reagent of Amines and Alcohols
Keumi, Takashi,Shimada, Masakazu,Morita, Toshio,Kitajima, Hidehiko
, p. 2252 - 2256 (2007/10/02)
A new trifluoroacetylating reagent, 2-(trifluoroacetyloxy)pyridine (TFAP), was prepared by the reaction of 2-pyridinol and trifluoroacetic anhydride.TFAP has been found to be effective in the trifluoroacetylation of aliphatic and aromatic amines and alcohols including phenol under mild conditions.The reaction of p-nitrophenol with TFAP in ether gave the hydrogen-bonded complex between the phenol and 2-pyridone.This reagent has also been shown to be useful for the intramolecular dehydration of aldehyde oximes and amides to give nitriles in high yields.
