SYNTHESIS, CHARACTERIZATION, ANTIBACTERIAL AND CYTOTOXIC EVALUATION OF NEW 6-(CHLOROTHIOPHENYL)-2-(2-OXOPROPOXY)PYRIDINE-3-CARBONITRILE DERIVATIVES AND THEIR CORRESPONDING FURO[2,3-b]PYRIDINE DERIVATIVES

The synthesis of a new series of 6-(chlorothiophenyl)-2-(2-oxopropoxy)pyridine-3-carbonitrile compounds 2 and 5 and their furo[2,3-b]pyridines bearing heteroaryl substituents 3 and 6 in high yield is reported. The 6-(chlorothiophenyl)-2-(2-oxopropoxy)pyridine-3-carbonitrile derivatives (2a-f) and (5a-d) were prepared from the corresponding 3-cyano-(2H)-pyridones (1a-f) and (4a-d) followed by the Thorpe-Ziegler ring cyclization in the presence of sodium methoxide to give the target furo[2,3-b]pyridine derivatives (3a-f) and (6a-d). Proposed structures of the new compounds are based on NMR and mass spectral data. Antibacterial evaluation of (2a-d), (2f), (5a-d), (3a-d), (3f), and (6a-d) derivatives against eight different microorganisms shows no activity towards any of the tested bacteria while compounds (6a) and (6c) showed weak antibacterial activity with inhibition zone of 10 mm. Cytotoxic assessment against MCF7 breast cancer cells reveals that 10 of the derivatives were found to decrease cell viability in a dose dependent manner at concentration of 100 mu M, but six of them decreased it to less than 50% and had IC50's ranging from 23.3 to 41.2 mu M.