Antimicrobial and antimycotic activity of some derivatives of 3-arylpyridin-2-one and 3-arylpyran-2-one

Abstract

2-Pyridones and 2-pyrones are a well-known heterocyclic compounds having significant biological and medical application. The molecular structures and various activities of 2-pyridone derivatives as well as their syntheses and natural occurrence are analyzed and discussed. Previously, we developed an effective method for the synthesis of 3-aryl-substituted derivatives of 2-pyranone. This method consists in the interaction of commercially available starting reagents with comercially available arenediazonium salts via the Meerwein reaction conditions. In this paper, we report on an effective method for the synthesis of 3-arylpyridin-2-ones starting from 3-arylpyranones. Reaction of methyl or ethyl esters of 4,6-dimethyl-3-aryl-2-oxo-2 H -5-pyrancarboxylic acids with ammonium acetate in acetic acid gave methyl or ethyl esters of 2,4-dimethyl-6-oxo-5-aryl-1,6-dihydropyridine-3-carboxylic acids in high yields. For some compounds (ethyl 4,6-dimethyl-3-(2-nitrophenyl)-2-oxo-2 H -pyran-5-carboxylate ( 1c ), ethyl 2,4-dimethyl-5-(4-nitrophenyl)-6-oxo-1,6-dihydropyridine-3-carboxylate ( 2c ), 6-methyl-3-(3-nitrophenyl)-2-oxo-2 H -pyran-5-carboxylic acid ( 5 ), 4-methyl-6-(2-methylprop-1-en-1-yl)-3-(4-nitrophenyl)-2 H -pyran-2-one ( 6 ), methyl 4,6-dimethyl-3-(2-nitrophenyl)-2-oxo-2 H -pyran-5-carboxylate ( 7 )) we investigated antifungal and antimicrobial activity. The antimicrobial activity of the obtained compounds ( 1c , 2c , 5 , 6 , 7 ) was studied by a micromethod using disposable 96-well sterile polystyrene tablets and Takachi microtiters. The test strains of bacteria were grown for 18–20 h on beveled meat-peptone agar (MPA) at a temperature of +37 ºС. The highest activity, especially of compound 6 , was found against "true" fungi ‑ strain № 7 (S. cerevisiae 61). Compounds 5 and 6 act on strain B. subtilis ATCC6633 at a concentration of 31.3 μg/ml. Keywords: pyran-2-one, pyridin-2-one, recyclization, antimicrobial activity, antifungal activity.