- A highly diastereoselective [3+3] annulation reaction of aza-oxyallyl cations and nitrones
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An efficient synthesis of 1,2,4-oxadiazinan-5-ones via [3+3] cycloaddition of in situ generated aza-oxyallyl cations with nitrones has been developed. The protocol features easy operation, excellent yields, excellent diastereo-control, broad substrate sco
- Chen, Rongxing,Sun, Shaofa,Wang, Gangqiang,Guo, Haibin
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supporting information
p. 1916 - 1920
(2018/04/19)
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- 1,3-Dipolar cycloadditions. Part XVII: Experimental and theoretical spectroscopic investigations of C-aryl-N-methyl nitrones
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Detailed experimental and theoretical spectroscopic studies of C-aryl-N-methyl nitrones have been reported. The optimized geometries have been calculated by DFT/B3LYP level of theory with 6-31+G(d,p) basis set. The theoretically computed frontier orbital
- Acharjee, Nivedita,Banerji, Avijit,Banerjee, Manas,Das, Tapas K.
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body text
p. 1627 - 1637
(2010/06/17)
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- Rapid, efficient, and room temperature synthesis of nitrones in excellent yields over MgO under solvent-free conditions
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A large variety of C-aryl and C-alkyl nitrones were synthesized within 0.5-15 min via the condensation of aldehydes with N-(methyl, phenyl, or t-butyl)hydroxylamines over MgO by hand-grinding with an agate mortar. These reactions were investigated under d
- Valizadeh, Hassan,Dinparast, Leila
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experimental part
p. 177 - 181
(2009/10/04)
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- 1,3-Dipolar cycloadditions. Part-XV: Systematic spectroscopic investigations of C-aryl-N-methylnitrones
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Several C-aryl-N-methylnitrones have been synthesised during the course of our work on 1,3-dipolar cycloadditions. Detailed systematic spectroscopic investigations of all these nitrones have been undertaken. These are reported along with some generalisati
- Banerji, Avijit,Acharjee, Nivedita,Biswas, Pizush Kanti
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scheme or table
p. 63 - 67
(2010/05/02)
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- Synthesis of 5-trichloromethyl-Δ4-1,2,4-oxadiazolines and their rearrangement into formamidine derivatives
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A series of 5-trichloro-Δ4-1,2,4-oxadiazolines have been synthesised by 1,3-dipolar cycloaddition of nitrones to trichloroacetonitrile. These oxadiazolines rearrange into formamidine derivatives, via ring opening and a 1,2-aryl shift from carbo
- Wagner, Gabriele,Garland, Tim
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p. 3596 - 3599
(2008/09/21)
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- Oxidation of secondary amines by molecular oxygen and cyclohexanone monooxygenase
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Cyclohexanone monooxygenase from Acinetobacter calcoaceticus catalyzed the oxidation of tertiary and secondary amines to N-oxides and nitrones, respectively. The formation of a hydroxylamine intermediate was involved with secondary amines as starting substrates.
- Colonna, Stefano,Pironti, Vincenza,Carrea, Giacomo,Pasta, Piero,Zambianchi, Francesca
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p. 569 - 575
(2007/10/03)
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- 1,3-Dipolar cycloadditions: Part VIII1-Microwave irradiation assisted synthesis of N-methyl-C-aryl nitrones
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N-Methyl-C-arylnitrones have been synthesized in very high yields within a few minutes from N-methyl-hydroxylamine hydrochloride and aryl aldehydes in presence of sodium hydrogen carbonate in methylene chloride using the microwave irradiation technique.
- Banerji, Avijit,Biswas, Pizush Kanti,Sengupta, Piyali,Dasgupta, Saugandha,Gupta, Maya
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p. 880 - 881
(2007/10/03)
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- The effects of lewis acid on the 1,3-dipolar cycloaddition reaction of C-arylaldonitrones with alkenes
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The regio- and stereoselectivity of the 1,3-dipolar cycloaddition reactions of C-aryl-N-alkylaldonitrones (1a-e) with some alkenes were found to be affected significantly by the addition of Lewis acid. The rate of the reaction was also affected by adding the Lewis acid. In the reactions using allyl alcohol as a dipolarophile an addition of Lewis acid caused a remarkable acceleration of the reaction and a great change in the stereoselectivity. In the reactions using ethyl acrylate as a dipolarophile the regioselectivity was reversed whether the reaction was performed in the presence or the absence of Lewis acid; i.e. isoxazolidine-5-carboxylates were obtained mainly in the absence of Lewis acid although isoxazolidine-4-carboxylates were obtained mainly in the presence of Lewis acid. When the reaction of C,N-diarylaldonitrones (1k, 1m, 1n) with ethyl acrylate was carried out in the presence of Lewis acid, the cleavage of the N-O bond of the cycloadducts giving γ-aminoalcohols was also observed besides a reverse phenomenon of regioselectivity.
- Shimizu, Tomio,Ishizaki, Masaya,Nitada, Nobuo
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p. 908 - 921
(2007/10/03)
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- Oxidation of N-benzyl-N-methylhydroxylamines to nitrones. A mechanistic study
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Oxidation of various N-(o-, m-, p- substituted benzyl)- N-methylhydroxylamines has been carried out using mercury(II) oxide and p-benzoquinone (p-BQ) as oxidants. Hammett plots have been obtained with negative ρ values, showing the development of a positive centre in the transition state. The unstable E nitrones, which readily isomerize to the more stable Z nitrones, are obtained in appreciable quantities and in some cases as the major product. A considerable deuterium isotope effect is observed in the oxidation process. The overall picture of the mechanistic pathway involves electron transfer from nitrogen to the oxidant followed by hydrogen abstraction.
- Hassan, Azfar,Wazeer, Mohammed I. M.,Ali, Sk. Asrof
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p. 393 - 399
(2007/10/03)
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