Polyfunctional dithiocarbamato-containing pyrroles: Synthesis and evaluation of antimicrobial and antioxidant activities

Abstract

A new effective method for the synthesis of 4- and 2-dithiocarbamato methyl substituted polyfunctional pyrroles 5 and 8 that is based on reduction of the corresponding 5-chloro-4-chloromethyl-1H-pyrrol-3-carboxylates 3 and 2-bromomethyl-5-chloro-4-cyano-1H-pyrrol-3-carboxylates 7 with dithiocarbamates of alkali metals or zinc 4 in a solution of DMF at 50 °C has been developed. The structural composition of all synthesized compounds was established by IR, ¹H NMR, and ¹³C NMR spectroscopy and chromatography combined with mass spectrometry. Then the antimicrobial activity of all synthesized compounds was checked against the bacterial strains (Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, Proteus vulgaris АТСС 4636, Pseudomonas aeruginosa АТСС 27853, and Klebsiella pneumoniae АТСС 13883) and fungi (Candida albicans АТСС 885/653 and Aspergillus niger K9). In addition, the inhibition ability of the compounds against radicals has also been checked. As can be seen from the obtained results, the MIC of the synthesized compounds against the germs ranges between 31.25 and 125 µg/mL, MBC – 31.25–250 µg/mL, and MFC – 62.5–125 µg/mL. On the other hand, the absorption value for the DPPH radicals in ethyl 5-chloro-4-cyano-2-{[(thiomorpholin-4-ylcarbonothioyl)thio]methyl}-1-methyl-1H-pyrrole-3-carboxylate 8b was 97.3%, while for ethyl 5-chloro-4-cyano-2-({[(dimethylamino)carbonothioyl]thio}methyl)-1-butyl-1H-pyrrole-3-carboxylate 8e it was 95.6%.