Phosphomolybdic acid/SiO2 as heterogeneous solid acid catalyst for the rapid synthesis of N-substituted pyrroles

Isatins react efficiently with 4-hydroxyproline in the presence of 10mol% of PMA/SiO2 in acetonitrile/water (4:1) under reflux conditions to furnish N-substituted pyrroles in excellent yields. Similarly, 11H-indeno[1,2-b]quinoxalin-11-ones also participated in this reaction.