- Ring-chain tautomerism of the novel 2-ferrocenyl-2,4-dihydro-1H-3,1- benzoxazine
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The synthesis and the study of the spectroscopic and electrochemical properties as well as the solution behavior of the novel 2-ferrocenyl-2,4- dihydro-1H-3,1-benzoxazine (1a) are described. NMR studies reveal the existence of a tautomeric equilibria between the cyclic (1a) and the open-chain form (2a). Electrochemical studies based on cyclic voltametry and 57Fe Moessbauer spectroscopy as well as a comparative study of the ring-chain tautomerism of 1a and that of 2-phenyl-2,4-dihydro-1H-3,1-benzoxazine (3a) are also reported.
- Perez, Sonia,Lopez, Concepcion,Caubet, Amparo,Roig, Anna,Molins, Elies
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- Synthesis of (η6-arene)tricarbonylchromium derivatives of 1,4-dihydro-3,1-benzoxazines
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A series of (η6-arene)tricarbonylchromium derivatives of 1,4-dihydro-3,1-benzoxazines was synthesized and characterized. The compounds were obtained by two alternative methods, namely, by the reaction of triammine(tricarbonyl)chromium with 1,4-dihydro-3,1-benzoxazines (method A) and by the condensation of (η6-2-aminobenzyl alcohol)tricarbonylchromium with various aldehydes and ketones (method B). The composition and structure of obtained compounds were established by different physicochemical methods of analysis, such as HPLC, UV, IR, 1H NMR spectroscopy, mass spectrometry, and X-ray diffraction.
- Sazonova,Artemov,Faerman,Aksenova,Timofeeva,Zaytseva, Yu. A.,Somov,Grishina, N. Yu.
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p. 171 - 178
(2021/03/02)
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- Phosphine-Catalyzed Reaction between 2-Aminobenzaldehydes and Dialkyl Acetylenedicarboxylates: Synthesis of 1,2-Dihydroquinoline Derivatives and Toward the Development of an Olefination Reaction
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A series of 1,2-dihydroquinolines were synthesized in good to excellent yields by reacting 2-aminobenzaldehyde derivatives and dialkyl acetylenedicarboxylates with catalytic amounts of phosphine. This reaction was rendered catalytic by the selective in situ phosphine oxide reduction with the use of phenylsilane. Furthermore, with the same starting materials and with an additional role of the reducing agent, a new olefination reaction was discovered. Hydrogen/deuterium (H/D) exchange experiments revealed the possible mechanism of this reaction.
- Han, Xu,Saleh, Nidal,Retailleau, Pascal,Voituriez, Arnaud
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p. 4584 - 4588
(2018/08/09)
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- Iron-catalyzed cascade reaction of 2-aminobenzyl alcohols with benzylamines: Synthesis of quinazolines by trapping of ammonia
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A novel approach to construct 2-aryl/heteroaryl quinazolines was developed through an iron-catalyzed cascade reaction of 2-aminobenzyl alcohols with benzylamines under aerobic oxidative conditions. The reaction proceeds via the formation of N-benzylideneb
- Gopalaiah, Kovuru,Saini, Anupama,Devi, Alka
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p. 5781 - 5789
(2017/07/22)
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- ABNO-Catalyzed Aerobic Oxidative Synthesis of 2-Substituted 4H-3,1-Benzoxazines and Quinazolines
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A new transition-metal-free 9-azabicyclo[3.3.1]nonan-N-oxyl (ABNO) catalyzed aerobic oxidative synthesis of 2-substituted 4H-3,1-benzoxazines and quinazolines has been developed through cascade reaction of aldehydes with 2-aminobenzyl alcohols and 2-amino
- Ma, Jiaqi,Wan, Yan,Hong, Chao,Li, Meichao,Hu, Xinquan,Mo, Weimin,Hu, Baoxiang,Sun, Nan,Jin, Liqun,Shen, Zhenlu
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p. 3335 - 3342
(2017/06/29)
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- Simple grinding-induced reactions of 2-aminobenzyl alcohol and benzaldehyde derivatives, a rapid synthetic route to 3,1-benzoxazines
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The grinding-induced reactions of 2-aminobenzyl alcohol and benzaldehyde derivatives in the presence of 30 mol% of acetic acid to give 3,1-benzoxazines are described. The reactions were performed at room temperature affording 3,1-benzoxazines in yields above 95% and high purity when benzaldehyde and its chloro and nitro derivatives were used.
- Masesane, Ishmael B.,Muriithi, Eva,Tabane, Tebogo H.
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p. 301 - 304
(2014/06/24)
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- Synthesis of 2-substituted quinazolines via iridium catalysis
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An iridium-catalyzed hydrogen transfer reaction was successfully applied in the synthesis of 2-substituted quinazolines in moderate yields starting from aldehydes or alcohols with 2-aminobenzylamines.
- Fang, Jie,Zhou, Jianguang,Fang, Zhijie
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p. 334 - 336
(2013/03/28)
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- CuCl/DABCO/4-HO-TEMPO-catalyzed aerobic oxidative synthesis of 2-substituted quinazolines and 4 H -3,1-benzoxazines
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The Cu/N-ligand/TEMPO catalytic system was first applied to the aerobic oxidative synthesis of heterocycles. As demonstrated, 2-substituted quinazolines and 4H-3,1-benzoxazines were synthesized efficiently from the one-pot reaction of aldehydes with 2-aminobenzylamines and 2-aminobenzyl alcohols, respectively, by employing CuCl/DABCO/4-HO-TEMPO as the catalysts and oxygen as the terminal oxidant.
- Han, Bing,Yang, Xiu-Long,Wang, Chao,Bai, Yong-Wei,Pan, Tai-Chao,Chen, Xin,Yu, Wei
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experimental part
p. 1136 - 1142
(2012/02/16)
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- Synthesis of 3h-quinazolin-4-ones and 4h-3,1-benzoxazin-4-ones via benzylic oxidation and oxidative dehydrogenation using potassium iodide-tert-butyl hydroperoxide
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A simple and elegant method for benzylic activation was demonstrated employing the potassium iodide/tert-butyl hydrogen peroxide catalytic system. This methodology was further extended for the synthesis of biologically important heterocycles namely, 3H-quinazolin-4-ones and 4H-3,1-benzoxazin-4-ones including mecloqualone and etaqualone which are important quinazolinone-based drugs used for the treatment of insomnia in good yields.
- Kumar, R. Arun,Maheswari, C. Uma,Ghantasala, Satheesh,Jyothi,Reddy, K. Rajender
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supporting information; experimental part
p. 401 - 410
(2011/04/18)
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- Highly efficient one-pot synthesis of 2-substituted quinazolines and 4H-benzo[d][1,3]oxazines via cross dehydrogenative coupling using sodium hypochlorite
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This communication describes a catalyst-free synthesis of 2-substituted quinazolines and 4H-benzo[d][1,3]oxazines using commericially available sodium hypochlorite as oxidant. Operational simplicity, mild reaction conditions and the ability to construct structurally diverse 2-quinazolines and 2-substituted 4H-benzo[d][1,3]oxazines by this method render it to be a practical alternative for the synthesis of these heterocycles.
- Maheswari, C. Uma,Kumar, G. Sathish,Venkateshwar,Kumar, R. Arun,Kantam, M. Lakshmi,Reddy, K. Rajender
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supporting information; experimental part
p. 341 - 346
(2010/04/28)
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- Application of daugulis copper-catalyzed direct arylation to the synthesis of 5-aryl benzotriazepines
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A method for the direct arylation of benzotriazepines is reported, employing an aryl iodide as the coupling partner, copper iodide as the catalyst, and lithium tert-butoxide as the base. A variety of electron-rich, electron-poor, and sterically hindered aryl iodides are compatible with the reaction conditions. The arylation reaction can also be performed outside a glovebox in air without a significant decrease in yield. Furthermore, convenient microwave conditions for carrying out this transformation are reported.
- Yotphan, Sirilata,Bergman, Robert G.,Ellman, Jonathan A.
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supporting information; experimental part
p. 1511 - 1514
(2009/08/07)
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- Synthesis and structure-activity relationship of 2-(aminoalkyl)-2,3,3a,8-tetrahydrodibenzo[c,f]isoxazolo[2,3-a]azepine derivatives: A novel series of 5-HT2A/2C receptor antagonists. Part 1
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The synthesis of a series of novel 2-(aminoalkyl)-2,3,3a,8-tetrahydrodibenzo[c,f]isoxazolo[2,3-a]azepine derivatives as well as their 5-HT2A/2C and H1 receptor binding affinities are described. The in vivo activity as potential anxiolytics of the synthesised compounds was measured in a mCPP challenge test. One of the compounds, 2a, proved to be a potent 5-HT2A/2C receptor antagonist showing as well oral activity and therefore could be considered as a potential anxiolytic/antidepressant agent.
- Andres,Alcazar, Jesus,Alonso, Jose M.,Diaz, Adolfo,Fernandez, Javier,Gil, Pilar,Iturrino, Laura,Matesanz, Encarna,Meert, Theo F.,Megens, Anton,Sipido, Victor K.
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p. 243 - 248
(2007/10/03)
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- Ring-Chain Tautomerism in 1,3-Oxazines
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A comparative study on the ring-chain tautomerism of 49 2-(substituted-phenyl) tetrahydro-1,3-oxazines of seven different types, namely, tetrahydro-1,3-oxazines 3,r-8a,c-2,c-4a- and r-8a,c-2,t-4a-1,3-perhydrobenzoxazines 5 and 7,r-8a,c-2,c-4- and r-8a,c-2,t-4a-1,3-perhydrobenzoxazines 9 and 11, 3,4-dihydro-2H-1,3-benzoxazines 12, and 1,2-dihydro-4H-3,1-benzoxazines 13, pointed out that in all cases the equilibria can be described with a simple equation, log Kx = (0.76 +/- 0.04)?+ + logKX=H where Kx = /(X/H).A factor c illustrating the sum of ster ic and electronic effects of substituents at C-4,C-5, and C-6 has also been introduced
- Fueloep, Ferenc,Pihlaja, Kalevi,Mattinen, Jorma,Bernath, Gabor
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p. 3821 - 3825
(2007/10/02)
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- Effect of p-Substitution on the Spectroscopic Properties of 1,2-Dihydro-4H-2-phenyl-3,1-benzoxazines
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A series of 1,2-dihydro-4H-2-phenyl-3,1-benzoxazines (I) were obtained by condensation of o-aminobenzyl alcohol and substituted benzaldehyde.The effect of p-substitution on their spectroscopic properties was investigated by uv and mass spectroscopy.
- Saeed, Ali A. H.
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p. 113 - 115
(2007/10/02)
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