Dendritic Amine on Mesoporous Silica: First Organo Base Catalyst for Paal Knorr Reaction under Solvent Free Condition, A green approach

We report for the first time a simple, highly efficient and ecofriendly approach for the preparation of pyrrole derivatives in the presence of dendritic amine grafted on mesoporous silica under solvent free condition. We have synthesized and characterized the three generations of dendritic amine grafted on mesoporous silica (G0-G2) through a stepwise growth technique. The maximum yield was observed with third generation (G2) and the catalyst was easily separated from the reaction mixture. Studies showed that dendritic effect of amino groups on the catalyst was the driving force of the reaction pathway, which has led to the formation of pyrrole derivatives. The green aspect of the present method are use of metal free catalyst, low catalyst loading, shorter reaction times, organic solvents are not needed, facile work-up, purification of the products by non-chromatographic methods, the excellent yield of the products, room temperature and the reusability of the catalyst.