Background: The simply prepared and characterized alkaline starch (AS) by a new co-grinding protocol represents a superior catalytic activity in two- or three-component synthesis of hydroquinazolinones from either 2-aminobenzonitrile, 2-aminobenzamide, or isatoic anhydride. All AS-catalyzed reactions occur in higher yield and faster than the earlier methodologies. These performances are due to the several basic sites and special polymeric structure of this green bioorganic base catalyst.
Methods: The alkaline starch (AS) was prepared by a new method based on co-grinding of starch with solid NaOH at room temperature. AS has been characterized by SEM, FT-IR spectroscopy, XRF, and base capacity. The efficacy of AS catalyst has been examined in the multi-strategic synthesis of hydroquinazolinones in water or under solvent free conditions.
Results: While AS consists of elements of C, H, O, and Na, it exhibits high base capacity, thermal stability, reusability, and high catalytic activity in more than 40 different sets of experiments for effective synthesis of hydroquinazolinones.
Conclusion: The first co-grinding preparation and application of alkaline starch as a biocompatible, cost effective, and reusable base catalyst has been developed. AS is a superior catalyst for highly efficient synthesis of hydroquinazolinones from either 2-aminobenzonitrile, 2-aminobenzamide, or isatoic anhydride in water or under solvent-free conditions.