Transformations de N-acylaziridines catalysées par des supports à base de silice et d’alumine : une élucidation mécanistique

Besbes, Néji; Jellali, Houyem; Pale, Patrick; Srasra, Ezzeddine

doi:10.1016/j.crci.2009.09.014

Cited by 11 publications

(13 citation statements)

References 25 publications

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“…The natural clay powder used in this work was withdrawn from the center region of Gabes, the South-East of Tunisia [30][31][32]. The purification process of clay went through several unit operations starting by crushing using a mortar.…”

Section: Purification Of Claymentioning

confidence: 99%

“…Some heterogeneous catalysts that have been applied for the acetalization of glycerol are Amberlyst-46, Amberlyst-36 [26], Amberlyst-15 [27], beta-zeolite [28], montmorillonite [18], acidic clay supported heteropolycatalyst [29] and acidic VMCM-41 [6]. Within this context, we studied the application of acid-activated clay as a heterogeneous catalyst owing to easy external adsorption and desorption of chemicals during the reaction, its low price, the small effort to apply for its separation from the liquid media and its low environmental impact [30]. Clays and modified clays are widely included in chemical reactions such as synthesis and rearrangements of heterocycles, additions reactions, condensations reactions, Diels-Alders reaction, imine synthesis, epoxidation and several more [29,31,32].…”

Section: Introductionmentioning

confidence: 99%

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Green Production of Glycerol Ketals with a Clay-Based Heterogeneous Acid Catalyst

et al. 2019

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Glycerol remains a bottleneck for the biodiesel industry as well as an opportunity from the biorefinery perspective, having a notable reactivity as a platform chemical. In particular, glycerol ketals can be envisaged as oxygenates for fuel formulation. In this study, we have focused on the green synthesis of glycerol ketals by reacting glycerol with acyclic (acetone, butanone) and cyclic (cyclohexanone) ketones in the presence of an acid activated clay Tunisian AC in homogeneous systems under quasi-solventless conditions. These reactions were followed by on-line Fourier Transform Infrared Spectroscopy (FTIR) (namely, ReactIR 10). Firstly, the contacting time was selected studying the activity, stability and chemical characteristics of a set of catalysts. The 1-h activated clay AC was further characterized by X-Ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electronic Microscopy with Energy Dispersive Spectroscopy (SEM/EDS). Finally, the effect of the main operational variables (catalyst concentration, reagents molar ratio, time and temperature) were checked and we reflected on adequate second-order kinetic models with partial first-order deactivation.

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Section: Purification Of Claymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Green Production of Glycerol Ketals with a Clay-Based Heterogeneous Acid Catalyst

et al. 2019

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“…Such a treatment resulted in the formation of three compounds 2, 3 and 4 and we conclude that the acid hydrolysis of aziridines 1a-c with acidified water (39-81%) is more efficient than the acid-activated clay (26-38%) as previously reported. 17,18 In addition, the reaction of N-benzoyl-2,2-dimethylaziridine 1c with 9% H 2 SO 4 by wt. in water leads to a mixture of products 2c, 3c and 4c with a combined yield of 50% which is much higher than the one obtained by the acid activated clay (30% yield).…”

Section: Resultsmentioning

confidence: 99%

“…A mixture of oxazolines, methallylamides and amidoalcohols was formed and the yields closely depended upon the aziridines 1. 17,18 In order to improve the selectivity of the reaction and to increase in the overall yield, we have now studied the acid hydrolysis reaction of N-acyl-2,2dimethylaziridines.…”

Section: Introductionmentioning

confidence: 99%

Experimental and theoretical rearrangement of N-acyl-2,2- dimethylaziridines in acidic medium

et al. 2016

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The acid isomerization of N-acyl-2,2-dimethylaziridines 1 in concentrated sulfuric acid at room temperature leads to oxazolines 2 but the neutral hydrolysis of 1 in pure water at room temperature leads to amidoalcohols 3. However, the use of aqueous solutions of H 2 SO 4 at different concentrations at room temperature leads to a mixture of oxazolines 2, amidoalcohols 3 and allylamides 4 with yields depending on the acidity of the medium and the nature of the acyl group. A mechanism has been suggested to explain the formation of these three products. DFT calculations employing the Gaussian 09 program with DFT/B3LYP methods and 6-311++G(2d,2p) basis set were carried out which gave the most stable geometry as well as their atomic charge distributions of compounds 1-4.

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“…This cyclization step could involve the formation of a carbocation and/or an aziridinic intermediate (Fig. 4) as recent studies demonstrated that Nacyl-2,2-dimethylaziridines could evolve into oxazolinic forms [26]. These two potential intermediates characterized by very short half-lifes, are difficult to observe in a biological context but it has been established that the aziridinium structures were clearly involved in DNA alkylation by N-nitrosoureas and nitrogen mustards [27].…”

Section: Discussionmentioning

confidence: 99%

Intramolecular cyclization of N-phenyl N′(2-chloroethyl)ureas leads to active N-phenyl-4,5-dihydrooxazol-2-amines alkylating β-tubulin Glu198 and prohibitin Asp40

Trzeciakiewicz¹,

Fortin²,

Moreau³

et al. 2011

Biochemical Pharmacology

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The cyclization of anticancer drugs into active intermediates has been reported mainly for DNA alkylating molecules including nitrosoureas. We previously defined the original cytotoxic mechanism of anticancerous N-phenyl-N'-(2-chloroethyl)ureas (CEUs) that involves their reactivity towards cellular proteins and not against DNA; two CEU subsets have been shown to alkylate β-tubulin and prohibitin leading to inhibition of cell proliferation by G₂/M or G₁/S cell cycle arrest. In this study, we demonstrated that cyclic derivatives of CEUs, N-phenyl-4,5-dihydrooxazol-2-amines (Oxas) are two- to threefold more active than CEUs and share the same cytotoxic properties in B16F0 melanoma cells. Moreover, the CEU original covalent binding by an ester linkage on β-tubulin Glu198 and prohibitin Asp40 was maintained with Oxas. Surprisingly, we observed that Oxas were spontaneously formed from CEUs in the cell culture medium and were also detected within the cells. Our results suggest that the intramolecular cyclization of CEUs leads to active Oxas that should then be considered as the key intermediates for protein alkylation. These results will be useful for the design of new prodrugs for cancer chemotherapy.

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Transformations de N-acylaziridines catalysées par des supports à base de silice et d’alumine : une élucidation mécanistique

Cited by 11 publications

References 25 publications

Green Production of Glycerol Ketals with a Clay-Based Heterogeneous Acid Catalyst

Green Production of Glycerol Ketals with a Clay-Based Heterogeneous Acid Catalyst

Experimental and theoretical rearrangement of N-acyl-2,2- dimethylaziridines in acidic medium

Intramolecular cyclization of N-phenyl N′(2-chloroethyl)ureas leads to active N-phenyl-4,5-dihydrooxazol-2-amines alkylating β-tubulin Glu198 and prohibitin Asp40

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