Utilization of 5‐Chloro‐2‐(cyanoacetamido)pyridines in the Synthesis of Biologically Active Heterocyclic Hybrids

Abstract

A simple synthesis for a series of chloropyridine derivatives incorporating heterocyclic hybrids has been accomplished. The key reaction involving employment of 5-chloro-2-(cyanoacetamido)pyridines 3 in the synthesis of chloropyridinyl-pyridone, chloropyridinyl-pyrazole, chloropyridinyl-thiazole and chloropyridinyl-thiophene hybrids. The newly synthesized heterocycles were evaluated for their antioxidant and antibacterial activities against Gram-positive and Gram-negative bacterial strains. 3-Amino-N-(3,5-dichloropyridin-2-yl)-1H-pyrazole-4-carboxamide (12 b) was found to be the most potent compound against Escherichia coli and Staphylococcus aureus exhibiting inhibition percent of 92.3 % and 100 %, respectively, when compared to the standard drug ampicillin. Moreover, compound 12 b displayed the most significant antioxidant activity with percent inhibition 87.8 % which is close to the antioxidant activity of ascorbic acid.

Thiophene‐containing compounds with antimicrobial activity

“…They were prepared through the thiophene ring closure of the corresponding α‐cyanoketene‐ N , S ‐acetals derived from 5‐chloro‐2‐(cyanoacetamido)pyridines, phenyl isothiocyanate and either ethyl bromoacetate or chloroacetone in the usual manner. [ 108 ] The activity of the four synthesized compounds 121 against E. coli was inferior to their activity against S. aureus (the activity of ampicillin against the same strains was used as reference), while the most potent compound among these thiophene–pyridine conjugates was 121 (R = CH 3; R 1 = H), whose activity index against S. aureus reached 95.8%.…”