A study on the Kabachnik–Fields reaction of benzaldehyde, propylamine, and diethyl phosphite by in situ Fourier transform IR spectroscopy

Keglevich, György; Fehérvári, András; Csontos, István

doi:10.1002/hc.20676

Cited by 17 publications

(17 citation statements)

References 25 publications

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“…All compounds prepared (1aee, 2aed, 3aed and 6aed) were characterized by 31 P, 13 Crystal structure of ring platinum complex 5b was determined by single crystal X-ray analysis. The resulting structure ( Fig.…”

Section: Synthesis Of New Bis(phospha-mannich Adducts)mentioning

confidence: 99%

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N-Benzyl and N-aryl bis(phospha-Mannich adducts): Synthesis and catalytic activity of the related bidentate chelate platinum complexes in hydroformylation

Bálint

Fazekas

Pongrácz

et al. 2012

Journal of Organometallic Chemistry

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Section: Synthesis Of New Bis(phospha-mannich Adducts)mentioning

confidence: 99%

“…One of the authors of this article with co-workers could prove the intermediacy of the imine intermediate in a few cases studied utilizing the method of in situ Fourier Transform Infrared spectroscopy [13,14].…”

Section: Introductionmentioning

confidence: 98%

N-Benzyl and N-aryl bis(phospha-Mannich adducts): Synthesis and catalytic activity of the related bidentate chelate platinum complexes in hydroformylation

Bálint

Fazekas

Pongrácz

et al. 2012

Journal of Organometallic Chemistry

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“…To investigate the reaction mechanism,o nline mass spectrometry was used to detect if any ammonia gas was produced in the reaction. [33][34][35][36][37][38][39] Benzylamine was adsorbed on the surfaceo f Bi 24 O 31 Br 10 .W ith light, the intensities of all vibrations were increaseda nd the coupling reactiono fa mines took place. To determine the origin of the hydrogen atoms in the produced ammonia,H 2 Ow as replaced with D 2 Oa nd the reaction repeated ( Figure 1b).…”

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confidence: 99%

“…As shown in Figure 1a,N H 3 was detected. [33][34][35][36][37][38][39] In contrast, the CÀHs ymmetric stretching vibrations of methylene (2850, 2922 and 2957 cm À1 ) were decreased. Both NH 3 and NDH 2 were generated during the reactionp rocess.…”

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confidence: 99%

“…To determine the origin of the hydrogen atoms in the produced ammonia,H 2 Ow as replaced with D 2 Oa nd the reaction repeated ( Figure 1b). [33][34][35][36][37][38][39] This indicated that benzaldehyde and benzoica cid were the important intermediates foro xidative coupling of amines to imines.B ased on the above findings, we have proposed ap hotocatalytic mechanism of oxidative coupling in water as follows: ( 1) Bi À O À Br þ hv ! This indicates that water is involved in the photocatalytic selective oxidative coupling of amines.I na ddition, in situ infrared spectroscopy revealed the intermediates of photocatalytic selectiveo xidative coupling of amines.A ss hown in Figure 1c, After 40 min adsorptiono fb enzylamineo ver Bi 24 O 31 Br 10 ,N H 2 rocking( 1263cm À1 ), CÀNs tretching vibration (1316 and 1342 cm À1 ), CÀCr ing stretching (1392 and 1458 cm À1 ), CÀH stretching (1426 cm À1 ), NÀHd eformationa nd CÀNs tretching (1521 cm À1 ), and absorbed water vibrations (1640 cm À1 )w ere detected.…”

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Visible‐Light‐Driven Selective Oxidative Coupling of Amines to Imines by Bismuth‐Rich Bismuth Oxybromide in Water

et al. 2019

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Photocatalytic selective oxidative coupling of amines is a promisingm ethod for imine synthesis. Bismuth-rich bismuth oxybromide photocatalysts have been found to exhibit improvedc onversion and selectivity for the visible-light-driven selectiveo xidative coupling of amines to imines in water.B enzylaminesw ith either electron-withdrawing or electron-donating groups undergo good conversion (94-99 %) and excellent selectivity (93-98 %) to the corresponding imines. The average apparent quantum efficiency at 455 nm is 57.4 %. Active species trapping experiments, isotope experiments, and in situ infrared spectroscopy reveal that water both serves as solvent and participates in the coupling reactiona sareactant. This work provides ag reen and environmentally friendly method for the efficient synthesis of imines with bismuth-richb ismuth oxyhalides and reveals water is involved in the oxidative coupling mechanismo fbenzylamines.Imines are an active intermediate in organic synthesis and can participate in reactions such as reductions, additions, condensations, and cycloadditions. [1] In addition, imine compounds show good antibacterial activities and have applicationsi n medicine and biology,o wing to their excellent pharmacological and biological activities. [2] Therefore, there is increased interest in the synthesis of imines by the hydrogenationo fn itro compounds, [3,4] oxidation and condensation of amines and alcohols, [5,6] and oxidative dehydrogenation of secondary amines. [7] However,t he above synthetic strategies are very difficult on an industrial scale because of the need for expensive reagentso rt oxic materials, and produce stoichiometric byproducts.T he oxidative coupling of amines to imines is an efficient route due to the high atomice conomy and environmentally friendly nature.This reactionist raditionally catalyzed thermally rather than photochemically,w hich is am ild, clean effi-cient method in organic synthesis. [8,9] Therefore, the photocatalytic oxidative coupling of amines was investigated asa promising methodf or imine synthesis.Optimized catalysts, solvents, andl ight sources are very important to achieveh igh selectivity and conversion in photocatalytic reactions. Currently,t he photocatalytic oxidative conversion of amines to imines has been investigated with several semiconductor systems, such as TiO 2 , [10][11][12][13][14] g-C 3 N 4 , [15][16][17] Nb 2 O 5 , [18,19] CdS, [20] ZnIn 2 S 4 , [21] MoS 2 , [22] and metal-organic frameworks MOFs). [23] However,t here are many shortcomings with these photocatalysts,s uch as UV excitation forT iO 2 and Nb 2 O 5 ,ahigh pressure of O 2 or high reaction temperatures requiredf or good conversion with g-C 3 N 4 and MoS 2 ,a nd the low photocatalytic stabilityo fC dS and ZnIn 2 S 4 .M ore importantly, the above systems typically require organic solvents, such as acetonitrile, benzene, or dichloromethane. Environmentally friendly approaches, according to the tenets of green chemistry,s hould limit the use of such organic solvents. Therefore, our approac...

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A study on the kabachnik‐‐fields reaction of benzaldehyde, cyclohexylamine, and dialkyl phosphites

Keglevich

Kiss

Menyhárd

et al. 2012

Heteroatom Chemistry

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The Kabachnik–Fields reaction of benzaldehyde, cyclohexylamine, and dimethyl phosphite carried out at 80°C in acetonitrile takes place via an imine (PhCNcHex) intermediate, as the monitoring by in situ Fourier transform IR spectroscopy suggested. The corresponding α‐hydroxyphosphonate was also formed in a quantity of 13% that was not converted to α‐aminophosphonate under the conditions applied. The outcome was similar to the Kabachnik–Fields reaction with diethyl phosphite as the P‐component. Molecular modeling and subsequent DFT calculations carried out under solventless conditions supported the experimental results and indicated the formation of a high number of ideally positioned H bonds as the key determinant for the conformation of the starting, intermediate, and product states. The relative energies of the possible intermediates were in accord with the observation that the formation of the α‐hydroxyphosphonate is a “dead‐end” route. © 2011 Wiley Periodicals, Inc. Heteroatom Chem 23:171–178, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/hc.20767

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A study on the Kabachnik–Fields reaction of benzaldehyde, propylamine, and diethyl phosphite by in situ Fourier transform IR spectroscopy

Abstract: The phospha-Mannich condensation of benzaldehyde, n-propylamine, and diethyl phosphite carried out at 80

Cited by 17 publications

References 25 publications

N-Benzyl and N-aryl bis(phospha-Mannich adducts): Synthesis and catalytic activity of the related bidentate chelate platinum complexes in hydroformylation

N-Benzyl and N-aryl bis(phospha-Mannich adducts): Synthesis and catalytic activity of the related bidentate chelate platinum complexes in hydroformylation

Visible‐Light‐Driven Selective Oxidative Coupling of Amines to Imines by Bismuth‐Rich Bismuth Oxybromide in Water

A study on the kabachnik‐‐fields reaction of benzaldehyde, cyclohexylamine, and dialkyl phosphites

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