Synthesis, characterization and cytotoxicity of new nicotinonitriles and their furo[2,3-b]pyridine derivatives

Abstract

The present research work describes the synthesis of new series of nicotinonitrile (2) and furo[2,3-b]pyridine (3) heterocycles bearing thiophene substituent. The nicotinonitrile derivatives were prepared from the corresponding 3-cyano-(2H)-pyridones (1a–f) in excellent yields. The ring cyclization of the nicotinonitrile derivatives (2a–f) in the presence of sodium methoxide provided the furo[2,3-b]pyridines (3a–f) in moderate to good yields. All the newly synthesized compounds were characterized by extensive NMR analysis data, including 1D-NMR experiments (¹H and ¹³C) and 2D-NMR experiments (COSY, HMBC, HSQC), as well as HRESIMS data. All the final products were subjected for cytotoxic activity against five different tumour cell lines including HeLa (cervical), DU145 (prostate), HepG2 (liver), MDA-MB-231 (breast-ER negative) and MCF7 (breast-ER positive), in addition to HSF1184 (normal human fibroblast) using the MTT assay. Compounds 2d and 3e were found to exhibit promising cytotoxicity with IC₅₀ of < 20 µM against all different tested tumour cell lines. In addition, these compounds showed high selectivity (40–287 folds) for tumour cells over normal cells.

Graphical abstract