- 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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- 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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- Studies on the Benzoxazine Series. 2- Preparation and 1H and 13C NMR Structural Study of Some Substituted 1,2-Dihydro-4H-3,1-benzoxazines
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In addition to the parent compounds, nine methyl-substituted 1,2-dihydro-4H-3,1-benzoxazines with and without N-methyl substitution were prepared.The chain tautomer could only be detected in the case of 1,2-dihydro-2-(p-nitrophenyl)-4H-3,1-benzoxazine in
- Neuvonen, Kari,Pohtola, Riitta,Pihlaja, Kalevi
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p. 725 - 733
(2007/10/02)
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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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