- Nickel(ii)-catalyzed asymmetric thio-Claisen rearrangement of α-diazo pyrazoleamides with thioindoles
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A nickel(ii) catalyzed enantioselective thio-Claisen rearrangement of α-diazo pyrazoleamides with thioindoles was realized with modified chiral N,N′-dioxide ligands, affording a variety of C3-substituted indole derivatives in high yields (up to 95%) with excellent enantioselectivities (up to 96% ee) under mild reaction conditions. A possible transition state model was proposed based on previous reports and the X-ray crystal structure of the catalyst.
- Yang, Wei,Lin, Xiaobin,Zhang, Yongyan,Cao, Weidi,Liu, Xiaohua,Feng, Xiaoming
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p. 10002 - 10005
(2020/09/15)
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- Kolbe-Schmitt type reaction under ambient conditions mediated by an organic base
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The combined use of an organic base for resorcinols realized a Kolbe-Schmitt type reaction under ambient conditions. When resorcinols (3-hydroxyphenol derivatives) were treated with DBU under a carbon dioxide atmosphere, nucleophilic addition to carbon dioxide proceeded to afford the corresponding salicylic acid derivatives in high yields.
- Sadamitsu, Yuta,Okumura, Akira,Saito, Kodai,Yamada, Tohru
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p. 9837 - 9840
(2019/08/20)
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- Photocatalytic Cleavage of Aryl Ether in Modified Lignin to Non-phenolic Aromatics
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Depolymerization of lignin meets the difficulty in cleaving the robust aryl ether bond. Herein, through installing an internal nucleophile in the β-O-4′ linkage, the selective cleavage of aryl ether was realized by the intramolecular substitution on aryl rings affording non-phenolic arylamine products. In particular, nitrogen-modified lignin models and lignin samples were employed to generate the iminyl radical under photocatalytic reduction, which acted as the internal nucleophile inducing aryl migration from O to the N atom. The following hydrolysis released primary arylamines and α-hydroxy ketones. Mechanism studies including electron spin resonance (ESR), fluorescence quenching experiments, and density functional theory (DFT) calculations proved the aryl migration pathway. This method enables access to non-phenolic arylamine products from lignin conversion.
- Li, Hongji,Bunrit, Anon,Lu, Jianmin,Gao, Zhuyan,Luo, Nengchao,Liu, Huifang,Wang, Feng
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p. 8843 - 8851
(2019/09/30)
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- Deacetylative Amination of Acetyl Arenes and Alkanes with C-C Bond Cleavage
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The Br?nsted acid-catalyzed synthesis of primary amines from acetyl arenes and alkanes with C-C bond cleavage is described. Although the conversion from an acetyl group to amine has traditionally required multiple steps, the method described herein, which uses an oxime reagent as an amino group source, achieves the transformation directly via domino transoximation/Beckmann rearrangement/Pinner reaction. The method was also applied to the synthesis of γ-aminobutyric acids, such as baclophen and rolipram.
- Hyodo, Kengo,Hasegawa, Genna,Maki, Hiroya,Uchida, Kingo
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supporting information
p. 2818 - 2822
(2019/04/25)
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- Cu(II)-Mediated N-H and N-Alkyl Aryl Amination and Olefin Aziridination
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Cu(II)-mediated direct NH2 and NH alkyl aryl aminations and olefin aziridinations are described. These room-temperature, one-pot, environmentally friendly procedures replace costly Rh2 catalysts and, in some instances, display important differences with comparable Rh2- and Fe-supported reactions.
- Munnuri, Sailu,Anugu, Raghunath Reddy,Falck, John R.
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supporting information
p. 1926 - 1929
(2019/03/11)
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- Expanding the Balz–Schiemann Reaction: Organotrifluoroborates Serve as Competent Sources of Fluoride Ion for Fluoro-Dediazoniation
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The Balz–Schiemann reaction endures as a method for the preparation of (hetero)aryl fluorides yet is eschewed due to the need for harsh conditions or high temperatures along with the need to isolate potentially explosive diazonium salts. In a departure from these conditions, we show that various organotrifluoroborates (RBF3?s) may serve as fluoride ion sources for solution-phase fluoro-dediazoniation in organic solvents under mild conditions. This methodology was successfully extended to a one-pot process obviating aryl diazonium salt isolation. Sterically hindered (hetero)anilines are fluorinated under unprecedentedly mild conditions in good-to-excellent yields. Taken together, this work expands the repertoire of RBF3?s to act as fluorine ion sources in an update to the classic Balz–Schiemann reaction.
- Mohy El Dine, Tharwat,Sadek, Omar,Gras, Emmanuel,Perrin, David M.
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supporting information
p. 14933 - 14937
(2018/09/25)
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- Staudinger reaction using 2,6-dichlorophenyl azide derivatives for robust aza-ylide formation applicable to bioconjugation in living cells
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Efficient formation of water- and air-stable aza-ylides has been achieved using the Staudinger reaction between electron-deficient aromatic azides such as 2,6-dichlorophenyl azide and triarylphosphines. The reaction proceeds rapidly and has been successfully applied to chemical modification of proteins in living cells.
- Meguro, Tomohiro,Terashima, Norikazu,Ito, Harumi,Koike, Yuka,Kii, Isao,Yoshida, Suguru,Hosoya, Takamitsu
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supporting information
p. 7904 - 7907
(2018/07/25)
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- Site-Selective Copper-Catalyzed Amination and Azidation of Arenes and Heteroarenes via Deprotonative Zincation
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Arene amination is achieved by site-selective C-H zincation followed by copper-catalyzed coupling with O-benzoylhydroxylamines under mild conditions. Key to this success is ortho-zincation mediated by lithium amidodiethylzincate base that is effective for a wide range of arenes, including nonactivated arenes bearing simple functionalities such as fluoride, chloride, ester, amide, ether, nitrile, and trifluoromethyl groups as well as heteroarenes including indole, thiophene, pyridine, and isoquinoline. An analogous C-H azidation is also accomplished using azidoiodinane for direct introduction of a useful azide group onto a broad scope of arenes and heteroarenes. These new transformations offer rapid access to valuable and diverse chemical space of aminoarenes. Their broad applications in organic synthesis and drug discovery are demonstrated in the synthesis of novel analogues of natural product (-)-nicotine and antidepressant sertraline by late-stage amination and azidation reactions.
- Hendrick, Charles E.,Bitting, Katie J.,Cho, Seoyoung,Wang, Qiu
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p. 11622 - 11628
(2017/08/30)
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- Preparation method of 4-acetamidoanisole
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The invention discloses a preparation method of 4-acetamidoanisole. The preparation method comprises the following step: performing an acetylation reaction on acetic anhydride and a compound as shown in a formula 3 to obtain a compound as shown in a formula 4, wherein the acetylation reaction is performed in the absence of glacial acetic acid. The preparation method is low in pollution, low in cost, short in reaction time, low in reaction temperature and mild in reaction condition.
- -
-
Paragraph 0088; 0089
(2017/11/04)
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- Sonication and Microwave-Assisted Primary Amination of Potassium- Aryltrifluoroborates and Phenylboronic Acids under Metal-Free Conditions
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The transition-metal-free generation of a series of primary arylamines from potassium aryltrifluoroborates and phenylboronic acids- is reported. The method uses a mild, inexpensive source of nitrogen (hydroxylamine-O-sulfonic acid) in cooperation with aqueous sodium hydroxide in acetonitrile. Both a sonication and a microwave-assisted method were developed, which are capable of converting ArBF3K functionalities into primary arylamines (ArNH2) in isolated yields of up to 78% (10 examples for each method). This report represents the first general method for the conversion of aryltrifluoroborates into primary arylamines under mild, transition-metal-free conditions in moderate to very good yields. The method is applicable to a wide array of substrates containing electron-donating, electron-neutral, or electron-withdrawing substituents. Both the sonication and microwave methods were also applied to the generation of anilines from phenylboronic acids in isolated yields of up to 96% (12 examples for each method) that were superior to existing room temperature methods in terms of yield, while also offering much shorter reaction times (15 min vs 16 h). In particular, the microwave method is the first to allow for the conversion of arylboronic acids containing strongly electron-withdrawing substituents into the corresponding anilines in good yields, along with electron-donating- substituents in very good to excellent yields.
- Kuik, Dale,McCubbin, J. Adam,Tranmer, Geoffrey K.
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p. 2555 - 2561
(2017/05/22)
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- Fe-Catalyzed Amination of (Hetero)Arenes with a Redox-Active Aminating Reagent under Mild Conditions
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A novel and efficient Fe-catalyzed direct C?H amination (NH2) of arenes is reported using a new redox-active aminating reagent. The reaction is simple, and can be performed under air, mild, and redox-neutral conditions. This protocol has a broad substrate scope and could be used in the late-stage modification of bioactive compounds. Mechanistic studies demonstrate that a radical pathway could be involved in this transformation.
- Liu, Jianzhong,Wu, Kai,Shen, Tao,Liang, Yujie,Zou, Miancheng,Zhu, Yuchao,Li, Xinwei,Li, Xinyao,Jiao, Ning
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supporting information
p. 563 - 567
(2017/01/18)
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- A base-mediated self-propagative Lossen rearrangement of hydroxamic acids for the efficient and facile synthesis of aromatic and aliphatic primary amines
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A variety of aromatic and aliphatic hydroxamic acids were converted to the corresponding primary amines via base-mediated rearrangement. This rearrangement could proceed with less than 1 equiv. of K2CO3 in polar solvents under thermal conditions with no external reagents. This rearrangement has several features including no external activating agents needed for promoting the rearrangement, less than one equivalent of a base is sufficient for the reaction, and a clean reaction in which only carbon dioxide is produced as a by-product. A self-propagating mechanism via an isocyanate intermediate is proposed and elementary reaction steps, namely, chain propagation reactions are supported by experiments.
- Ohtsuka, Naoya,Okuno, Moriaki,Hoshino, Yujiro,Honda, Kiyoshi
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p. 9046 - 9054
(2016/10/05)
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- Compounds for modulating TRPV3 function
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The present application relates to compounds and methods for treating pain and other conditions related to TRPV3.
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Page/Page column 155
(2016/11/24)
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- Transition-metal-free access to primary anilines from boronic acids and a common +NH2 equivalent
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Diversely substituted anilines are prepared by treatment of functionalized arylboronic acids with a common, inexpensive source of electrophilic nitrogen (H2N-OSO3H, HSA) under basic aqueous conditions. Electron-rich substrates are found to be the most reactive by this method. However, even moderately electron-poor substrates are well tolerated under the room temperature conditions. Sterically hindered substrates appear to be equally effective compared to unhindered ones. Highly electron-deficient substrates afford product in very low yields at room temperature, but moderate to good yields are obtained at refluxing temperatures. Our method is also amenable to electrophilic amination of several common boronic acid derivatives (e.g., pinacol esters). We demonstrate that it can be combined with metal-halogen exchange reactions or a variety of directed ortho metalation protocols in a "one-pot" sequence for the synthesis of aromatic amines with unique substitution patterns. DFT studies, in combination with experimental results, suggest that the reaction occurs via base-mediated activation of HSA, followed by 1,2 aryl B-N migration. This mode of activation appears to be critical for the success of the reaction and allows, for the first time, a general, electrophilic amination of boronic acids at ambient temperature.
- Voth, Samantha,Hollett, Joshua W.,Mccubbin, J. Adam
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p. 2545 - 2553
(2015/03/18)
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- Self-propagated Lossen rearrangement induced by a catalytic amount of activating agents under mild conditions
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A mild self-propagated Lossen rearrangement induced by a catalytic amount of activating agents in medium to high polar organic solvents has been developed. The rearrangement of aromatic and aliphatic hydroxamic acids in the presence of a catalytic amount (0.01 equiv) of acetic anhydride and an equimolar amount of base such as well-dried potassium carbonate afforded the corresponding amines in high yields. This alternative to traditional Lossen rearrangement provides a simple and mild method for the synthesis of amines from free hydroxamic acids.
- Hoshino, Yujiro,Shimbo, Yuki,Ohtsuka, Naoya,Honda, Kiyoshi
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supporting information
p. 710 - 712
(2015/01/30)
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- A molecular balance for measuring aliphatic CH-π interactions
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A series of conformationally flexible bicyclic N-arylimides were employed as molecular balances to study the weak aliphatic CH-π interaction between alkyl and arene groups. The formation of intramolecular CH-π interactions in the folded conformers was characterized by X-ray crystallography. The strengths of the interactions were characterized in CDCl3 by the changes in the folded/unfolded ratios, as measured by 1H NMR. The CH-π interaction between a methyl group and an aromatic surface was ~1.0 kcal/mol and was easily disrupted or masked by conformational entropy and repulsive steric interactions.
- Carroll, William R.,Zhao, Chen,Smith, Mark D.,Pellechia, Perry J.,Shimizu, Ken D.
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supporting information; experimental part
p. 4320 - 4323
(2011/10/05)
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- Synthesis and biological evaluation of phenstatin metabolites
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Previous investigations on the incubation of phenstatin with rat and human microsomal fractions revealed the formation of nine main metabolites. The structures of eight of these metabolites have been now confirmed by synthesis and their biological properties have been reported. Eaton's reagent was utilized as a convenient condensing agent, allowing, among others, a simple multigram scale preparation of phenstatin. Synthesized metabolites and related compounds were evaluated for their antiproliferative activity in the NCI-60 cancer cell line panel, and for their effect on microtubule assembly. Metabolite 23 (2′-methoxyphenstatin) exhibited the most potent in vitro cytotoxic activity: inhibition of the growth of K-562, NCI-H322M, NCI-H522, KM12, M14, MDA-MB-435, NCI/ADR-RES, and HS 578T cell lines with GI50 values 50 = 3.2 μM vs 15.0 μM) and induced G2/M arrest in murine leukemia DA1-3b cells. The identification of this active metabolite led to the design and synthesis of analogs with potent in vitro cytotoxicity and inhibition of microtubule assembly.
- Ghinet, Alina,Rigo, Beno?t,Hénichart, Jean-Pierre,Le Broc-Ryckewaert, Delphine,Pommery, Jean,Pommery, Nicole,Thuru, Xavier,Quesnel, Bruno,Gautret, Philippe
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supporting information; experimental part
p. 6042 - 6054
(2011/11/29)
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- Base-mediated rearrangement of free aromatic hydroxamic acids (ArCO-NHOH) to anilines
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Without using activating agents, a variety of free aromatic hydroxamic acids could be rearranged to aromatic amines in the presence of base alone. The Royal Society of Chemistry 2009.
- Hoshino, Yujiro,Okuno, Moriaki,Kawamura, Eri,Honda, Kiyoshi,Inoue, Seiichi
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supporting information; experimental part
p. 2281 - 2283
(2009/09/06)
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- Compounds for modulating TRPV3 function
-
The present application relates to compounds and methods for treating pain and other conditions related to TRPV3.
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Page/Page column 56
(2010/11/28)
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- Endothelin antagonists
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A compound of the formula (I): or a pharmaceutically acceptable salt thereof is disclosed, as well as processes for and intermediates in the preparation thereof, and a method of antagonizing endothelin.
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- Synthesis of novel orthoalkylaminophenol derivatives as potent neuroprotective agents in vitro.
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A series of orthoalkylaminophenol derivatives was synthesized and tested in vitro with respect to their neuroprotective effect. Some of these compounds exhibited a potent antioxidant activity close to that of standard α-tocopherol.
- Larget, Ronan,Lockhart, Brian,Pfeiffer, Bruno,Neudorffer, Anne,Fleury, Maurice-Bernard,Largeron, Martine
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p. 2929 - 2934
(2007/10/03)
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- New Methods and Reagents in Organic Synthesis. 60. A New Synthesis of Aromatic and Heteroaromatic Amines Using Diphenyl Phosphorazidate (DPPA)
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Aromatic and heteroaromatic organometallics (Grignard and lihium compounds) reacts with diphenyl phosphorazidate (DPPA) to give labile phosphinyltriazenes.A study of the conversion of phosphinyltriazenes into amines has revealed that reductive work-up with aluminum hydride gives much better results than acidic or alkaline work-up.Sequential treatment of aromatic and heteroaromatic organometallics with DPPA, followed by aluminum hydride provides a convenient new method for the preparation of aromatic and heteroaromatic amines.Keywords - organometallic; aromatic halide; Grignard compound; organolithium compound; aromatic amine; heteroaromatic amine; phosphinyltriazene; hydride reduction; diphenyl phosphorazidate
- Mori, Shigehiro,Aoyama, Toyohiko,Shioiri, Takayuki
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p. 1524 - 1530
(2007/10/02)
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- NEW METHODS AND REAGENTS IN ORGANIC SYNTHESIS. 40. AMINATION OF AROMATIC AND HETEROAROMATIC ORGANOMETALLICS USING DIPHENYL PHOSPHORAZIDATE (DPPA)
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Amination of aromatic and heteroaromatic organometallics is efficiently achieved by sequential treatment with diphenyl phosphorazidate (DPPA) and sodium bis(2-methoxyethoxy)aluminium hydride in a one-pot process.
- Mori, Shigehiro,Aoyama, Toyohiko,Shioiri, Takayuki
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p. 429 - 432
(2007/10/02)
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- The Thermolysis of Polyazapentadienes. Part 4. Formation of Indoles and Quinoxalines from 5-(2,6-Disubstituted phenyl)-1,2,5-triazapentadienes and Related Compounds
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7-Methylindole and 5-substituted quinoxalines are the principal cyclised products from the qas-phase thermolyses of the hydrazones (2) and (5) and the oxime ester (7).Both heterocyclic systems arise by competitive decomposition of the spirodienyl radical, e.g. (18), the indole by loss of MeCN and a hydrogen atom, and the quinoxalines by loss of a methyl radical.
- McNab, Hamish
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p. 377 - 380
(2007/10/02)
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- A NOVEL AMINATION OF AROMATIC AND HETEROAROMATIC COMPOUNDS
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Vinyl azides act as NH2(+) equivalents in reaction with aromatic or heteroaromatic lithium derivatives thus providing a direct method for amination of such compounds.
- Hassner, Alfred,Munger, Paul,Belinka, A. Benjamin, Jr
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p. 699 - 702
(2007/10/02)
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