Quaternary salts of pyridoxal oxime have been synthesized by the quaternization of pyridoxal oxime with substitutedphenacylbromides using microwave heating. Microwave-assisted rapid synthesis was done both in solvent (acetone) and under solvent-free conditions. Good to excellent yields (58%-94%) were obtained in acetone in very short reaction times (3-5 min) as well as in the solvent-free procedure
吡哆醛肟的季盐已通过使用微波加热将吡哆醛肟与取代的苯甲酰溴季铵化而合成。微波辅助快速合成在溶剂(丙酮)和无溶剂条件下进行。在丙酮中在非常短的反应时间(3-5 分钟)以及在无溶剂程序中(42%-78%)在非常短的反应时间(7- 10 分钟)。介绍了制备吡哆醛肟季盐的有效方法,具有环保、易于处理和反应时间较短的优点。通过单晶 X 射线衍射法明确证实了化合物 7 的结构,其中 4-氟苯酰基部分与吡啶环氮原子键合。
Menshutkin Reaction in Choline Chloride-based Deep Eutectic Solvents
作者:V. Bušić、D. Gašo-Sokač
DOI:10.1080/00304948.2022.2117968
日期:2023.3.4
Published in Organic Preparations and Procedures International: The New Journal for Organic Synthesis (Vol. 55, No. 2, 2023)
发表于国际有机制剂和程序:有机合成新期刊(印刷前,2022 年)
Novel and Cleaner Synthesis of Pyridinium Salts from Pyridoxal Oxime and Substituted Phenacyl Bromides
An efficient green synthesis of quaternary pyridinium salts by liquid-assisted grinding (LAG) is reported. A series of reactions of pyridoxal oxime with substituted phenacyl bromides was carried out in a mortar and pestle. This new and cleaner method provides several advantages such as being environmentally friendly, using a simple workup procedure, and affording moderate to excellent yields. All products were deduced from their IR, NMR spectroscopic and elemental analysis data.
Synthesis and evaluation of novel analogues of vitamin B6 as reactivators of tabun and paraoxon inhibited acetylcholinesterase
A series of novel pyridinium oximes was prepared by reactions of quaternization of pyridoxal oxime with substituted phenacyl bromides in acetone at room temperature. The structures of compounds were determined according to the data obtained by IR spectroscopy, mass spectrometry, H-1 and C-13 nuclear magnetic resonance spectroscopy as well as by elemental analysis. We tested pyridoxal oxime (1) and five prepared oximes in 1 mM concentration as reactivators of human erythrocytes acetylcholinesterase (AChE) inhibited by organophosphorus compounds tabun and paraoxon: 1-phenacyl-3-hydroxy-4-hydroxyiminomethyl-5-hydroxymethyl-2-methylpyridinium bromide (2), 1-(4'-chlorophenacyl)-3-hydroxy-4-hydroxyiminomethyl-5-hydroxymethyl-2-methylpyridinium bromide (3), 1-(4'-fluorophenacyl)-3-hydroxy-4-hydroxyiminomethyl-5-hydroxymethyl-2-methylpyridinium bromide (4), 3-hydroxy-4-hydroxyiminomethyl-5-hydroxymethyl-2-methyl-1-(4'-methylphenacyl)pyridinium bromide (5), 3-hydroxy-4-hydroxyiminomethyl-5-hydroxymethyl-2-methyl-1-(4'-methoxyphenacyl)pyridinium bromide (6). However, tested oximes were not efficient in reactivation of either tabun or paraoxon inhibited AChE. The maximum restored enzyme activity in 24 h was below 25%. Therefore, this class of compounds cannot be considered as potential improvement in a search for new and more efficient antidotes against OP poisoning. (C) 2010 Elsevier Ireland Ltd. All rights reserved.