Nano Sulfated Titania as a Heterogeneous Solid Acid Catalyst for the Synthesis of Pyrroles by Clauson–Kaas Condensation under Solvent-free Conditions

A new and environmentally benign method for the preparation of N-substituted pyrroles from one-pot condensation reaction of 2,5-dimethoxytetrahydrofuran with amines and diamines in the presence of nano sulfated titania under solvent-free conditions is presented. This new protocol features simple operation, easy availability, stability, and eco-friendliness of catalyst, as well as high to excellent yields of products. In addition, we report for the first time an alternative method for the synthesis of pyrroles from aromatic amines containing the β-lactam fragment using nano sulfated titania as catalyst.