Novel Synthetic Routes to Quaternary Pyridinium Salts and their Antifungal Activity

Autor: Valentina Bušić, Karolina Vrandečić, Tamara Siber, Sunčica Roca, Vice Tomičić, Dajana Gašo Sokač
Jazyk: angličtina
Rok vydání: 2022
Předmět:
Zdroj: Croatica Chemica Acta
Volume 95
Issue 1
ISSN: 0011-1643
1334-417X
Popis: Eleven pyridine derivatives were prepared by quaternization reactions by different synthetic routes: conventional, microwave, and ultrasound. Since acetone and other solvents used in conventional quaternization reactions are harmful, attempts were made to replace the organic solvents with more environmentally friendly alternative - deep eutectic solvents. The reactions were carried out using pyridine-3-aldoxime, pyridine-4- aldoxime, isonicotinamide and nicotinamide as nucleophiles and three different dihaloalkanes as electrophiles: diiodopropane, dibromopropane and diiodohexane. The results showed that the microwave method using acetone as solvent was significantly faster and gave higher yields than the conventional method. In contrast, synthesis in the eutectic solvents choline chloride : urea gave significantly lower yields. The structures of the synthesized compounds were confirmed by 1H and 13C NMR spectroscopy, mass spectrometry and elemental analysis. The antifungal activity of all compounds was tested at two different concentrations (10 and 100 µg mL–1) against Botrytis cinerea, Fusarium culmorum, Macrophomina phaseolina and Sclerotinia sclerotiorum in vitro. All tested compounds showed excellent inhibitory activity against the studied phytopathogenic fungal species at a concentration of 100 µg mL–1.
Databáze: OpenAIRE