- One-Pot Generation of Benzynes from Phenols: Formation of Primary Anilines by the Deoxyamination of Phenols
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Benzynes were selectively generated in situ from phenols and trapped regioselectively with potassium hexamethyldisilazide to form primary anilines following acidic workup. The direct conversion of a phenolic hydroxyl group into a free amino group is a useful method for the preparation of primary aryl amines that are hard to synthesize by using coupling reactions involving phenol derivatives with ammonia. Whereas reactions of ortho- and meta-substituted phenols produced meta-substituted anilines exclusively, those of para-substituted phenols provided ortho-silylanilines.
- Akai, Shuji,Ikawa, Takashi,Masuda, Shigeaki
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- C-H Amination of Arenes with Hydroxylamine
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This Letter describes the development of a TiIII-mediated reaction for the C-H amination of arenes with hydroxylamine. This reaction is applied to a variety of electron-rich (hetero)arene substrates, including a series of natural products and pharmaceuticals. It offers the advantages of mild conditions (room temperature), fast reaction rates (30 min), compatibility with ambient moisture and air, scalability, and the use of inexpensive commercial reagents.
- See, Yi Yang,Sanford, Melanie S.
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supporting information
p. 2931 - 2934
(2020/04/09)
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- Pyridyl Radical Cation for C?H Amination of Arenes
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Electron-transfer photocatalysis provides access to the elusive and unprecedented N-pyridyl radical cation from selected N-substituted pyridinium reagents. The resulting C(sp2)?H functionalization of (hetero)arenes furnishes versatile intermediates for the development of valuable aminated aryl scaffolds. Mechanistic studies that include the first spectroscopic evidence of a spin-trapped N-pyridyl radical adduct implicate SET-triggered, pseudo-mesolytic cleavage of the N?X pyridinium reagents mediated by visible light.
- R?ssler, Simon L.,Jelier, Benson J.,Tripet, Pascal F.,Shemet, Andrej,Jeschke, Gunnar,Togni, Antonio,Carreira, Erick M.
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supporting information
p. 526 - 531
(2019/01/04)
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- Copper mediated C-H amination with oximes: En route to primary anilines
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Here we report an efficient Cu(i)-mediated C-H amination reaction with oximes as amino donors to introduce NH2 groups directly. Various strongly coordinating heterocycles including quinoline, pyrimidine, pyrazine, pyrazole and triazole were tolerated well. The potential utility was further demonstrated in a late-stage modification of telmisartan (an antagonist for the angiotensin II receptor).
- Xu, Lin-Lin,Wang, Xing,Ma, Biao,Yin, Ming-Xing,Lin, Hai-Xia,Dai, Hui-Xiong,Yu, Jin-Quan
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p. 5160 - 5164
(2018/06/21)
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- Preparation method of m-alkylaniline
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A preparation method of m-alkylaniline employs reduction of m-alkylazobenzene to prepare m-alkylaniline, and the reduction may be carried out in two ways; to be specific, in the first way, m-alkylazobenzene, a metal, an acid and a solvent are added directly into a reactor, wherein the metal is iron or zinc, the acid is acetic acid or hydrochloric acid, the solvent is methanol or ethanol, reacting proceeds at room temperature for 24 h, and a product is separated to obtain the m-alkylaniline; in the second way, the reduction is carried out through catalytic hydrogenation to obtain the product m-alkylaniline. The preparation method of the invention is simple and has few steps.
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Paragraph 0009
(2017/10/31)
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- A synthesis method of uncle-butyl phenol
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The invention relates to a method for synthesizing 3-(tert-butyl)phenol. The method includes the following steps that 4-tert-butyl-1-chlorobenzene serves as a raw material and is nitrated to obtain 1-chlorine-4-tert-butyl-2-nitrobenzene; the 1-chlorine-4-tert-butyl-2-nitrobenzene is reduced to generate 3-tert-butylaniline; the 3-tert-butylaniline is diazotized and subjected to a hydrolysis reaction, and the 3-(tert-butyl)phenol is obtained. According to the path, the raw material is cheap and easy to get, elementary reaction conditions of the steps are mild, after-treatment is simple, the four-step reaction total yield is high, the 3-(tert-butyl)phenol with the purity higher than 97% can be obtained through distilling, and industrial production prospects are achieved.
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Paragraph 0021; 0023
(2017/09/12)
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- Ruthenium-catalyzed meta/ortho-selective C-H alkylation of azoarenes using alkyl bromides
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meta/ortho-Selective CAr-H (di)alkylation reactions of azoarenes have been achieved via [Ru(p-cymene)Cl2]2 catalyzed ortho-metalation using various types of alkyl bromides. Particularly, dual meta-alkylation of azoarene and reduction offer an attractive strategy for the synthesis of meta-alkylanilines, which are difficult to access via traditional aniline functionalization methods.
- Li, Gang,Ma, Xingxing,Jia, Chunqi,Han, Qingqing,Wang, Ya,Wang, Junjie,Yu, Liuyang,Yang, Suling
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p. 1261 - 1264
(2017/02/05)
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- Selective reduction of halogenated nitroarenes with hydrazine hydrate in the presence of Pd/C
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A large variety of halogenated nitroarenes have been selectively reduced with hydrazine hydrate in the presence of Pd/C to give the corresponding (halogenated) anilines in good yield.
- Li, Fang,Frett, Brendan,Li, Hong-Yu
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p. 1403 - 1408
(2014/06/23)
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- An enantioselective fluorescence sensing assay for quantitative analysis of chiral carboxylic acids and amino acid derivatives
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A chiral 1,8-diacridylnaphthalene-derived fluorosensor exhibiting a C 2-symmetric cleft designed for stereoselective interactions with hydrogen bond donors has been used for the determination of both concentration and enantiomeric composition of carboxylic acids and amino acid derivatives. The Royal Society of Chemistry 2006.
- Wolf, Christian,Liu, Shuanglong,Reinhardt, Brian C.
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p. 4242 - 4244
(2007/10/03)
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- HIV protease inhibitors
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The present invention relates to novel dihydropyrones with tethered heterocycles having improved pharmacologic properties which potently inhibit the HIV aspartyl protease blocking HIV infectivity. The dihydropyrones are useful in the development of therapies for the treatment of viral infections and diseases, including AIDS. The present invention is also directed to methods of synthesis of the dihydropyrones and intermediates useful in the preparation of the final compounds.
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- Thiocyanation of alkylanilines. A simple and efficient synthesis of thiosulfonates containing 2-aminobenzothiazole
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Thiocyanation of anilines was used to introduce a thiol functionality and to construct the aminothiazole ring, all in a single step. A systematic study of thiocyanation of alkyl anilines was investigated to understand the regio-chemistry of the reaction. X-Ray crystal structures of two 2- aminobenzothiazoles were determined to assign the structures without any ambiguity. The intermediates obtained were further expanded to thiosulfonates containing 2-aminobenzothiazoles, which are extremely valuable intermediates to synthesize HIV protease inhibitors. (C) 2000 Elsevier Science Ltd.
- Vara Prasad,Panapoulous,Rubin, John R.
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p. 4065 - 4068
(2007/10/03)
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- Preparation of aromatic amines
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Aromatic amines (anilines) are obtained directly or via the corresponding cycloaliphatic amines by an aminating/hydrogenating reaction of phenols with ammonia and hydrogen over a supported palladium catalyst which also contains elements from group 1b, 2b or 7b of the periodic table as well as iron, cobalt or nickel, as such or in the form of their compounds, and, preferably, an inorganic base, said catalysts also having dehydrogenating properties.
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- Polar Effects in Free Radical Reactions. Homolytic Aromatic Amination by the Amino Radical Cation, +NH3: Reactivity and Selectivity
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Small amounts of Fe(II) salt initiate redox chains with hydroxyamino-O-sulfonic acid (HSA) and aromatic compounds leading to the amination of the aromatic ring.The positional and substrate selectivity with a variety of substituted benzenes show the important role of the electrophilic character of the radical +NH3.Hammett relationships with ? and ?+ are roughly observed.The lower sensitivity to polar effects of the radical +NH3 compared with (CH3)2+NH is explained by the different reaction enthalpies.The different positional selectivity obtained with anisole and the redox system +NH3OH/Ti(III) is discussed.
- Citterio, Attilio,Gentile, Anna,Minisci, Francesco,Navarrini, Valter,Serravalle, Marco,Ventura, Susanna
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p. 4479 - 4482
(2007/10/02)
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- Preparation of primary aromatic amines from cyclic alcohols and/or ketones
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Aromatic amines, in particular substituted amines, are obtained from corresponding alicyclic alcohols or ketones, in one step, by amination and dehydrogenation with ammonia in the presence of hydrogen and of a palladium catalyst which also contains zinc or cadmium.
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