Understanding nucleophilicity of pyridine-N-oxides towards 2,4,6-trinitrophenylbenzoate through simple absorption spectroscopic studies

IF 0.9 Q4 CHEMISTRY, PHYSICAL

Current Organocatalysis Pub Date : 2023-08-08 DOI:10.2174/2213337210666230808152832

Sarifuddin Gazi, Ladapborlang Mawrie, Fazlur Rahman

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Abstract

Understanding nucleophilicity of poor nucleophiles like pyridine-N-oxides. Nucleophilicity plays a vital role in substitution reactions. It helps to determine the possibility and extent of the substitution reactions. The study of the nucleophilicity of poor nucleophiles is challenging, and it has limited substrate scope. Understanding the strength of nucleophilicity of such poor nucleophiles in a quantitative way is important. Understanding the strength of nucleophilicity of such poor nucleophiles in a quantitative way. Selection of appropriate electrophile for the reactions with the poor nucleophiles-pyridine-N-oxides. Development of suitable methodology for kinetic studies of the reaction. UV-Vis spectroscopic methods for monitoring the reactions. The kinetic studies revealed that the second-order rate constants of the nucleophilic reactions are 1.67× 102 L mol-1 minute-1, 2.51 L mol-1 minute-1, 29.8 L mol-1 minute-1, where the nucleophiles are p-methylpyridine-N-oxide, pyridine-N-oxide, and p-nitropyridine-N-oxide, respectively. The UV-Vis spectroscopic analysis revealed the nucleophilicity of p-methylpyridine-N-oxide > pyridine-N-oxide > p-nitropyridine-N-oxide. This comparative study suggests that the strength of nucleophilicity of the p-methylpyridine-N-oxide is 5.6 times and 66.53 times more than that of pyridine-N-oxide and p-nitropyridine-N-oxide, respectively, whereas the strength of nucleophilicity of the pyridine-N-oxide is 11.87 times more than that of p-nitropyridine-N-oxide.

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简单吸收光谱研究吡啶-N-氧化物对2,4,6-三硝基苯甲酸酯的亲核性

了解贫亲核试剂如吡啶-N-氧化物的亲核性。亲核性在取代反应中起着至关重要的作用。它有助于确定取代反应的可能性和程度。研究贫亲核试剂的亲核性具有挑战性，并且其底物范围有限。以定量的方式了解这种较差的亲核试剂的亲核性强度是很重要的。以定量的方式理解这种较差的亲核试剂的亲核性强度。选择合适的亲电试剂与贫亲核试剂吡啶-N-氧化物反应。开发合适的反应动力学研究方法。紫外-可见光谱法监测反应。动力学研究表明，亲核反应的二阶速率常数分别为1.67×102L mol-1 minute-1、2.51L mol-1 minute和29.8L mol-1 minute-1，其中亲核试剂分别为对甲基吡啶-N-氧化物、吡啶-N-氧化物和对硝基吡啶-N-氧化物。紫外-可见光谱分析揭示了对甲基吡啶-N-氧化物>吡啶-N-氧化物>对硝基吡啶-N-氧物的亲核性。该比较研究表明，对甲基吡啶-N-氧化物的亲核强度分别是吡啶-N-和对硝基吡啶-N-的5.6倍和66.53倍，而吡啶-N-氧化物的亲核性强度是对硝基吡啶-N氧化物的11.87倍。

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来源期刊

Current Organocatalysis CHEMISTRY, PHYSICAL-

CiteScore

2.00

自引率

0.00%

发文量

期刊介绍： Current Organocatalysis is an international peer-reviewed journal that publishes significant research in all areas of organocatalysis. The journal covers organo homogeneous/heterogeneous catalysis, innovative mechanistic studies and kinetics of organocatalytic processes focusing on practical, theoretical and computational aspects. It also includes potential applications of organocatalysts in the fields of drug discovery, synthesis of novel molecules, synthetic method development, green chemistry and chemoenzymatic reactions. This journal also accepts papers on methods, reagents, and mechanism of a synthetic process and technology pertaining to chemistry. Moreover, this journal features full-length/mini review articles within organocatalysis and synthetic chemistry. It is the premier source of organocatalysis and synthetic methods related information for chemists, biologists and engineers pursuing research in industry and academia.