Nanocrystalline titania-based sulfonic acid (TiO2-Pr-SO3H) as a new, highly efficient, and recyclable solid acid catalyst for preparation of quinoxaline derivatives

Nanocrystalline titania-based sulfonic acid (TiO2-Pr-SO3H) was used as an efficient and reusable catalyst for the synthesis of quinoxalines. The clean and mild acidity condition, quantitative yields of products, short reaction time, and low reaction temperature are attractive features of this method, making it suitable for heat-or acid-sensitive substrates, particularly in drug synthesis. In practice, this method affords an advantageous combination of satisfactory yields, easy product isolation, and purification.