Ultrasonic-Assisted Synthesis and Quantum Chemical Analysis of Spiro[Indoline-3,3′-Pyrazol]-2-One Derivatives as Effective Bactericidal and Viricidal Agents.

The present work described a novel synthesis of spiro[indoline-3,3′-pyrazol]-2-one derivatives 2, 4, 5, and 7 via a one-pot reaction of chalcones or β-aroyl acrylic acid 1a–c, isatin, and hydrazine derivatives e.g. hydrazine hydrate, methyl hydrazine, phenylhydrazine or acetohydrazide in sonicated reaction condition. The unexpected product 1,3-oxazino[3,2-a]indol-10-yl-ethanone derivative 6 can be generated instead of N-acetyl spiro[indoline-3,3′-pyrazol]-2-one as desired. Also, the Spiropyrazole-fused furanone and pyridazinone ring can be made. Owing to their unique 3-dimensional structures, spirooxindoles have been found as lucky chemotypes for antiviral drug enhancement in an attempt to achieve these spiropyrazole derivatives 2–10 with hydrophobic groups. Furthermore, the density functional theory (DFT) was used to elucidate the electronic and structural features of spiropyrazole derivatives and their reactive species, which supports the proposed mechanism of antibacterial and antiviral capabilities. [ABSTRACT FROM AUTHOR]