Synthesis, molecular structure, quantum mechanical studies and urease inhibition assay of two new isatin derived sulfonylhydrazides

Abstract

Two new isatin derivatives (E)-N′-(1-allyl-2-oxoindolin-3-ylidene)-4-methylbenzenesulfono-hydrazide (5) and (E)-N′-(1-allyl-2-oxoindolin-3-ylidene)-4-chlorobenzenesulfono-hydrazide (6) were synthesized in good yields by adopting two component synthetic methodology. The structure elucidation was accomplished with the help of UV–vis., FT-IR and NMR (1H and 13C) spectroscopic techniques. Suitable crystals were grown by slow evaporation method and structures were confirmed unequivocally with the help of single crystal X-ray diffraction analysis. Both isatin derivatives 5 and 6 exist in triclinic crystal packing having space group P-1. Crystal structures of both compounds showed that the geometries are stabilized by several intermolecular hydrogen bonds. Quantum mechanical calculations performed at density functional theory (DFT) level confirmed the experimental spectroscopic (UV–vis., FT-IR and 1H NMR) as well as X-ray diffraction results. Kinetic stability, reactivity, electrophilicity and nucleophilic behavior of both the derivatives was elaborated using frontier molecular orbitals (FMOs) and molecular electrostatic potential (MEP) analyses. Enzyme inhibition potential of both compounds was tested in vitro against Bacillus pasteurii urease and both compounds retarded the enzymatic activity with IC50 values of 39.46 ± 0.12 μM and 148.35 ± 0.16 μM respectively.