A Sulfonated Phenanthrolinum Salt of Phosphotungstate as Novel Catalyst for the Efficient Synthesis of 3,3-Diaryloxindoles

A novel heteropolyanion-based BrOnsted acidic ionic liquid (BAIL) material [PhBs](3)PW12O40, butane mono sulfoacid-functionalized phenanthrolinum salt of phosphotungstate catalyst (PhBs-PW), was synthesized and characterized with FTIR, H-1 and C-13 NMR, Electro-Spray Ionization Mass Spectrometry (ESI-MS), EDX, FE-SEM, and TG analysis. The new prepared catalyst was used for the efficient synthesis of 3,3''-diaryloxindole derivatives from the condensation of indole with isatins in water under reflux condition. The resultant condensation reaction using the introduced catalyst showed high yields of the products up to 97% and good recyclability of the catalyst confirmed in eight reusability runs.

Automated summary

A novel heteropolyanion-based BrOnsted acidic ionic liquid material [PhBs](3)PW12O40, known as butane mono sulfoacid-functionalized phenanthrolinum salt of phosphotungstate catalyst (PhBs-PW), was synthesized and characterized using various techniques. The newly prepared catalyst exhibited high product yields of up to 97% in the condensation reaction and showed good recyclability in eight reusability runs.