REACTION OF 1-ANTIPYRYL-4-AROYL-5-METHOXYCARBONYL-1H-PYRROLE-2,3-DIONES WITH ARYLAMINES

Abstract

In this work, we investigated the reaction of 1-antipyryl-4-aroyl-5-methoxycarbonyl-1H-pyrrole-2,3-diones with aromatic amines, which resulted in the production of 1-antipyryl-5-arylamino-4-aroyl-3-hydroxy-5-methoxycarbonyl-1H-pyrrol-2-ones. The reactivity of previously synthesized antipyryl-substituted monocyclic 1H-pyrrole-2,3-diones was studied using the example of reactions with NH-mononucleophilic reagents such as aniline, p-toluidine and 1-naphthylamine. The studied 1-antipyryl-4-aroyl-5-methoxycarbonyl-1H-pyrrole-2,3-diones are generated by boiling 1-antipyryl-4-aroyl-3-hydroxy-5-chloro -1,5-dihydro-1H-pyrrol-2-ones in an absolute toluene environment for 20-30 min, followed by distillation of part of the solvent and hydrogen chloride. Arylamines were added to the resulting concentrated hot solution in a 1:1 ratio. The resulting adduct is a light yellow crystalline substance. Apparently, the reaction of 1-antipyryl-4-aroyl-5-methoxycarbonyl-1H-pyrrole-2,3-diones with aromatic amines occurs through a nucleophilic attack by the amino group at the most electron-deficient position of the pyrrole ring. For all synthesized compounds, physical properties are given, such as solubility, melting points. The elemental composition was determined, and the structure of the molecules is established using NMR and IR spectroscopy. The 1H NMR spectra of solutions of the obtained compounds contain two singlets of the protons of the methyl groups of the antipyryl fragment in the region of 2.17-2.18 ppm. and 3.17-3.19 ppm, singlet of protons of the methoxycarbonyl group in the region of 3.69-3.71 ppm, singlet of protons of the amino group in the region of 6.53-6.68 ppm (1H, NH). The IR spectra of the products contain stretching vibrations of the ketone group in the region of 1653-1658 cm-1, the ester carbonyl group in the region of 1716-1718 cm-1, as well as a signal in the region of 3375-3388 cm-1 (NH). The described interaction proceeds quickly and with high yields. The reaction is a convenient preparative method for the synthesis of 1-antipyryl-5-arylamino-4-aroyl-3-hydroxy-5-methoxycarbonyl-1H-pyrrol-2-ones, which are of interest for further study of various types of biological activities, such as antimicrobial, anti-inflammatory, analgesic and others.