A DFT Study on Formation of Bisaryl Oxime Ether from Benzaldehyde and Phenoxyamine

Wang, Guilei; Chen, Yue; Zhong, Ai-Guo; Du, Hongguang; Lei, Ming

doi:10.1246/cl.2008.656

Cited by 3 publications

(1 citation statement)

References 11 publications

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“…Elimination of the protonated hydroxyl group results in the formation of hydrochloride salts of ( E )- and ( Z )-stereoisomers (fast reaction step). In acidic conditions, the protonation of the nitrogen atom follows with the transfer of the proton via an explicit water molecule to the hydroxyl group [ 26 , 27 ].…”

Section: Resultsmentioning

confidence: 99%

Polytopal Rearrangement Governing Stereochemistry of Bicyclic Oxime Ether Synthesis

Spahić¹,

Hrenar²,

Primožič³

2022

IJMS

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In the present study, four O-substituted oximes of quinuclidin-3-one were synthesized using appropriate O-substituted hydroxylamine hydrochlorides. In order to perform these reactions in a solvent, a mixture of (E) and (Z) products was yielded. Using mechanochemical and microwave synthesis, we then obtained pure (E) oximes. In almost all cases, the conversion to oxime ethers was completed. Reactions were monitored by ATR spectroscopy and the ratios of (E) and (Z) oxime ethers were deduced from 1H NMR data. Several reactions were very rapid (1 min) with 100% conversion and stereospecificity. To investigate the reaction mechanisms, full conformational analyses of the reaction intermediates were performed and the lowest energy conformers were determined. These conformers differed in spatial arrangement around the nitrogen atom of the amino group and were in the correct orientation for reactions to occur. Calculated standard Gibbs energies of the formation were in agreement with the experimentally obtained ratios of (E) and (Z) isomers. This work shows alternatives to the classical synthesis of O-substituted oxime ether precursors and highlights the fast reaction rate and stereoselectivity of microwave synthesis as well as the “green” aspects of mechanochemistry.

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Section: Resultsmentioning

confidence: 99%

Polytopal Rearrangement Governing Stereochemistry of Bicyclic Oxime Ether Synthesis

Spahić¹,

Hrenar²,

Primožič³

2022

IJMS

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Mechanistic study on the Knorr pyrazole synthesis-thioester generation reaction

et al. 2019

Tetrahedron Letters

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Understanding the Role of Water in Promoting E-Isomer Production and Photochromism of Solid Schiff Base: A DFT and Td-DFT Study

Zhong

Chen

Lei

et al. 2008

J. Theor. Comput. Chem.

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The formation mechanism and photochromic property of a novel solid state Schiff base compound (E-isomer, C 21 H 18 I 2 N 3 O 2) derived from 4-aminoantipyrine and 3,5-diiodosalicylaldehyde is investigated in this work using density functional theory at the B3LYP/6-31l++G** level with and without solvent water presence. Our computational results show that the conversion in the gas phase is unlikely to occur and the solvent water is involved in the reaction to decrease the barrier height. We considered one to three water molecule participations in the water-catalyzed mechanism to produce the E-isomer. Time-dependent density functional theory (B3LYP/6-311+G*) is employed to examine the photochromic property of the molecule. A large Stokes shift between absorption and emission has been attributed to the intramolecular H-transfer ( O – H ⋯ N to O ⋯ H – N ) following photoexcitation of the enol species, suggesting that the keto form of the photoproduct structure plays the key role, in agreement with the experimental finding of stereoselectivity. Conceptual DFT reactivity indices are employed to rationalize the findings from the present study.

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A DFT Study on Formation of Bisaryl Oxime Ether from Benzaldehyde and Phenoxyamine

Cited by 3 publications

References 11 publications

Polytopal Rearrangement Governing Stereochemistry of Bicyclic Oxime Ether Synthesis

Polytopal Rearrangement Governing Stereochemistry of Bicyclic Oxime Ether Synthesis

Mechanistic study on the Knorr pyrazole synthesis-thioester generation reaction

Understanding the Role of Water in Promoting E-Isomer Production and Photochromism of Solid Schiff Base: A DFT and Td-DFT Study

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