- A simple method for the reduction of Schiff bases using biosynthesized nickel oxide nanoparticles
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An innovative and simple approach for the reduction of aldimines to the corresponding secondary amines was described using biosynthesized nickel oxide nanoparticles as heterogeneous catalyst and ammonium formate as the hydrogen donor. This catalytic trans
- Muthuvinothini, Alagesan,Stella, Selvaraj
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p. 267 - 271
(2020/07/07)
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- Screening of simple carbohydrates as a renewable organocatalyst for the efficient construction of 1,3-benzoxazine scaffold
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A convenient protocol for the two component preparation of 1,3-benzoxazines by using several protected and unprotected carbohydrate molecules as organocatalysts have been developed which is broadly applicable to condensation reaction between variety of Ma
- Y?ld?r?m, Ayhan,Kaya, Yunus,G?ker, Mustafa
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- Metal-Free Diaryl Etherification of Tertiary Amines by Ortho-C(sp2)-H Functionalization for Synthesis of Dibenzoxazepines and -ones
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A phenyliodine(III) diacetate mediated umpolung reactivity of the tertiary amines with suitably substituted o-hydroxybenzyl and phenyl groups is exploited to facilitate o-C(sp2)-H functionalization to afford diaryl ethers. The presence of an o-
- Jamsheena, Vellekkatt,Mahesha, Chikkagundagal K.,Joy, M. Nibin,Lankalapalli, Ravi S.
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supporting information
p. 6614 - 6617
(2017/12/26)
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- Influence of substituent on equilibrium of benzoxazine synthesis from Mannich base and formaldehyde
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N-Substituted aminomethylphenol (Mannich base) and 3,4-dihydro-2H-3- substituted 1,3-benzoxazine (benzoxazine) were synthesized from substituted phenol (p-cresol, phenol, p-chlorophenol), substituted aniline (p-toluidine, aniline, p-chloroaniline) and formaldehyde to study influence of substituent on equilibrium of benzoxazine synthesis from Mannich base and formaldehyde. 1H-NMR and charges of nitrogen and oxygen atoms illustrate effect of substituent on reactivity of Mannich base, while oxazine ring stability is characterized by differential scanning calorimetry (DSC) and C-O bond order. Equilibrium constants were tested from 50 °C to 80 °C, and the results show that substituent attached to phenol or aniline has same impact on reactivity of Mannich base; however, it has opposite influence on oxazine ring stability and equilibrium constant. Compared with the phenol-aniline system, electron-donating methyl on phenol or aniline increases the charge of nitrogen and oxygen atoms in Mannich base. When the methyl group is located at para position of phenol, oxazine ring stability increases, and the equilibrium constant climbs, whereas when the methyl group is located at the para position of aniline, oxazine ring stability decreases, the benzoxazine hydrolysis tends to happen and equilibrium constant is significantly low. the Partner Organisations 2014.
- Deng, Yuyuan,Zhang, Qin,Zhou, Qianhao,Zhang, Chengxi,Zhu, Rongqi,Gu, Yi
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p. 18341 - 18348
(2014/09/30)
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- A quick route for the synthesis of 3-Aryl-3,4-dihydro-2H-benz[e]-1,3- oxazin-2-ones
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N-(2-Hydroxy)-benzyl-arylamines (1) gave substantially pure 3-aryl-3,4-dihydro-2H-benz[e]-1,3-oxazin-2-one 2 on cyclization with carbonyldiimidazole in DMSO in 20-30 min at 20-25 °C in excellent yields.
- Shukla, Davender Kumar,Rani, Manju,Khan, Arif Ali
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p. 4537 - 4540
(2013/06/27)
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- Efficient synthesis of 2,3-disubstituted-1,3-benzoxazines by chlorotrimethylsilane-mediated aza-acetalizations of aromatic aldehydes
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A series of novel substituted 3,4-dihydro-2H-1,3-benzoxazines were prepared in moderate to good yields by aza-acetalizations of aromatic aldehydes with 2-(N-substituted aminomethyl)phenols in the presence of chlorotrimethylsilane or SnCl4. It w
- Tang, Zilong,Zhu, Zhonghua,Yan, Lin,Chang, Shuhong,Liu, Hanwen
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p. 1116 - 1120
(2013/10/21)
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- Synthesis and biological activity of some 3-aryl-3,4-dihydro-2h-benz[e]-1, 3-oxazines/6-bromo-3-aryl-3,4-dihydro-2h-benz[e]-1,3-oxazines
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N-(2-Hydroxy)-benzyl-arylamine (1) gives substantially pure 3-aryl-3,4-dihydro-2H-benz[e]-1,3-oxazines/6-bromo-3-aryl-3,4-dihydro-2H-benz[e] -1,3-oxazines (2) on cyclization with formaldehyde in methanol within 0.5-1.0 h at 65-68 C in excellent yields. Th
- Shukla, Davender Kumar,Rani, Manju,Khan, Arif Ali,Tiwari, Kavita,Gupta, Rajinder K.
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p. 5921 - 5924
(2013/07/26)
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- SnCl4-catalyzed aza-acetalization of aromatic aldehydes: Synthesis of aryl substituted 3,4-dihydro-2H-1,3-benzoxazines
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Stannic tetrachloride was an efficient Lewis acid catalyst for the aza-acetalization of aromatic aldehydes with o-arylaminomethyl phenols, and a series of novel aryl substituted 3,4-dihydro-2H-1,3-benzoxazines were prepared in good yields under mild condi
- Tang, Zilong,Chen, Weiwen,Zhu, Zhonghua,Liu, Hanwen
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scheme or table
p. 1372 - 1383
(2012/04/04)
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- Synthesis and fungicidal activity of novel 2,3-disubstituted-1,3- benzoxazines
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A series of new 2,3-disubstituted-3,4-dihydro-2H-1,3-benzoxazines were prepared in moderate to excellent yields by aza-acetalizations of aromatic aldehydes with 2-(N-substituted aminomethyl)phenols in the presence of TMSCl. Their structures were confirmed
- Tang, Zilong,Zhu, Zhonghua,Xia, Zanwen,Liu, Hanwen,Chen, Jinwen,Xiao, Wenjing,Ou, Xiaoming
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scheme or table
p. 8174 - 8185
(2012/09/25)
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- Synthesis of 2,3-diaryl-3,4-dihydro-2H-1,3-benzoxazines and their fungicidal activities
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A series of novel 2,3-diaryl-3,4-dihydro-2H-1,3-benzoxazines have been prepared in high yields from o-arylaminomethylphenols and aromatic aldehydes in the presence of SnCl4 for the first time, and their fungicidal activities were investigated t
- Tang, Zilong,Chen, Weiwen,Zhu, Zhonghua,Liu, Hanwen
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p. 255 - 260
(2011/06/19)
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- Indium-mediated tandem dimerization and cyclization of nitrqones and aldimines to 3-arylaminodihydrobenzofurans under aqueous conditions
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Nitrones undergo deoxygenative reductive coupling and subsequent cyclization to 3-arylamino-2,3-dihydrobenzofuran derivatives in the presence of indium under aqueous conditions at ambient temperature in good yields.
- Jeevanandam, Arumugasamy,Ling, Yong-Chien
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p. 4361 - 4362
(2007/10/03)
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- The Condensation of Cyclic Anhydrides with Schiff Bases. A Convenient Synthesis of 1,4,6-Triaryl-5-carboxy-2-oxo-1,2-dihydropyridines and 2,3-Diaryl-4-carboxy-1-oxo-1,2-dihydroisoquinolines
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Condensation of Schiff bases of o-hydroxyarenecarboxaldehydes with 3-arylpentenedioic or homophthalic acid anhydrides was found to give 1,4,6-triaryl-5-carboxy-2-oxo-1,2-dihydropyridines and 2,3-diaryl-4-carboxy-1-oxo-1,2-dihydroisoquinolines, respectivel
- Mayadeo, M. S.,Kulkarni, S. J.,Deodhar, K. D.
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- New Route for the Preparation of 2H-3-Aryl-3,4-dihydro-1,3-benzoxazines and 2H-3-Aryl-3,4-dihydro-4-methyl-1,3-benzoxazines
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2-Hydroxybenzaldehyde (1) and 1-(2-hydroxyphenyl)ethanone (2) on reaction with different primary aromatic amines gave 2-(arylimino)methylphenols (3) and 2-phenols (4), respectively. 3 and 4 on reduction with sodium borohydride gave 2-(arylamino)methylphenols (5) and 2-phenols (6), which underwent cyclisation with formaldehyde to form 2H-3-aryl-3,4-dihydro-1,3-benzoxazines (7) and 2H-3-aryl-3,4-dihydro-4-methyl-1,3-benzoxazines (8), respectively.
- Joglekar, S. J.,Samant, S. D.
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p. 110 - 111
(2007/10/02)
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- BORCHELATE VON SALICYLALDEHYDNITRONEN
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Nitrones of salicylaldehyde react as bidentate ligands with various chelate-forming boron compounds resulting in seven-membered heterocycles with B,N-betaine structure.During the chelate-forming cyclization of the instable intermediate nitrone-adducts of the boron compounds suitable leaving groups from the boron are easily eliminated together with the phenolic proton of the salicylaldehyde moiety.
- Kliegel, Wolfgang,Nanninga, Dierk
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p. 373 - 386
(2007/10/02)
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