A facile synthesis of novel 5‐substituted pyridine 2 carboxamide derivatives and their biological evaluation and 3D QSAR studies

Abstract

A variety of novel 5‐substituted pyridine 2 carboxamides were designed and synthesized using both normal and solvent‐free microwave (MW) irradiation techniques. The results revealed that MW protocol proceeded smoothly under mild reaction conditions in short reaction times, thus avoiding the use of toxic organic solvents. Structural elucidation of the synthesized compounds was carried out on the basis of various spectroscopic methods, such as 1H NMR, 13C NMR, LCMS, and IR. The synthesized compounds were evaluated for their in vitro antimicrobial activity (MIC) using the agar disk diffusion method. Among the various synthetic compounds, compound 3b showed higher potential activity against Escherichia coli than the other compounds. The order of activity against E. coli of the studied compounds is 3b > 3e > 3g > 3h > 3d > 3c > 3a > 3f. Additionally, 2D and 3D structural features of the synthesized derivatives were recognized by the 3D‐QSAR model. This validated model exhibited good internal (r2, 0.924) and external prediction (r2pred, 0.851) correlation. The results of QSAR studies concluded that Alog P, the number of hydrogen bond acceptors, and the number of rotatable bonds were necessary features for the activity of the pyridine carboxamide derivatives.

Design, Synthesis, and Herbicidal Activity of Substituted 3-(Pyridin-2-yl)Phenylamino Derivatives

“…Compounds 3b and 3c were prepared using the same method. 27 The 1 H NMR characterization data for compounds 3a−3c are provided in the Supporting Information.…”

“…The solvent was evaporated, and the resulting mixture was subjected to column chromatography to isolate compound 3a . Compounds 3b and 3c were prepared using the same method . The 1 H NMR characterization data for compounds 3a – 3c are provided in the Supporting Information.…”