Ordered short channel mesoporous silica modified with 1,3,5-triazine–piperazine as a versatile recyclable basic catalyst for cross-aldol, Knoevenagel and conjugate addition reactions with isatins

Abstract

A triazine–piperazine immobilized on ordered short channel mesoporous silica was synthesized, characterized and used as a heterogeneous basic catalyst in the synthesis of indole skeletal structures from isatin derivatives under ambient reaction conditions in good to excellent isolated yields. The catalyst showed no loss in its efficacy over 10 recycle experiments.