Ammonium Chloride (NH4Cl): An Efficient and Environmentally Benign Catalyst for One-pot Synthesis of Xanthene Derivatives Under Solvent-free Conditions

摘要

A highly efficient environmentally benign protocol has been developed for the condensation of aromatic aldehydes with 1,3-diketones under solvent-free conditions. Various aromatic aldehydes were used for the condensation with cyclohexa-1,3-diones in the presence of efficient and inexpensive ammonium chloride catalyst, and in all cases, the products were synthesized successfully with good to excellent yield. The structures of all the new compounds were confirmed by infrared, H-1-nuclear magnetic resonance (NMR), C-13-NMR, and elemental analyses. The present method provides several advantages such as short reaction time, eco-friendly reaction medium, convenient, and simple operation.