Expeditious microwavable one-pot synthesis and biological exploration of spiro[indoline-3,4′-pyrazolo[3,4-b] pyridine derivatives

A rapid and efficient microwave-promoted one-pot strategy has been utilized to synthesize differentially functionalized spiro[indoline-3,4 '-pyrazolo[3,4-b] pyridine derivatives. Different optimized reaction conditions have been exploited when one-pot four-component (hydrazines, 1,3-dicarbonyl compounds, isatin, and malononitrile) reactions took place to afford satisfying yields of compounds [5-28]. Among different methodologies, the catalyst-free microwave-assisted fusion process has been proved to be the strategy with desirable traits to give good-to-excellent yields of the target compounds. Structural features of the obtained compounds were confirmed by the basis of elemental analyses, mass, H-1-NMR, and C-13-NMR spectrometry.