Synthesisand Characterization of Benzothiophene‐3‐carbonitrile Derivative and Its Interactions with Human Serum Albumin (HSA)

A series of biologically active compounds, i. e ., benzothiophene‐3‐carbonitrile derivatives, were synthesized from 1,3‐cyclohexanediones and malononitrile in the presence of base using the well‐known Gewald reaction. This recyclable approach resulted in significant improvement in overall yield (85‐90%), high purity and minimized production of chemical waste without using toxic reagents. The formation of compound, 2‐amino‐7‐oxo‐4,5,6,7‐tetrahydro‐1‐benzothiophene‐3‐carbonitrile ( 3 a ) was additionally supported by X ‐ray crystallography and was found to crystallize in P 2 1 /n space group. The mode of binding of 3 a with human serum albumin (HSA) was studied by FTIR, UV spectroscopy, fluorescence spectroscopy, circular dichroism (CD) and molecular docking studies. The fluorescence results establish that compound 3 a interacted with HSA via static quenching mechanism with a binding affinity of 11.49 × 10 −4  mol −1 and Gibbs free energy change (ΔG) of−6.8 kcal mol −1 . Molecular docking has been used to calculate the probable mode of interaction of compound 3 a with HSA.