Introduction of [SuSA-H]HSO4, as an efficient and reusable catalyst for the synthesis of 3,4‑dihydropyrimidin‑2(1H)‑ones/thiones

In the past few decades, dihydropyrimidinones (DHPMs), as an important class of heterocyclic compounds, have attracted great attention in medicinal and synthetic organic chemistry owing to their pharmacological and therapeutic properties such as antihypertensive and antibacterial activities. In addition, these compounds exhibit vital medicinal properties as calcium channel blockers, as well as anti-tumor activities. The Bigineli reaction based on a one-pot condensation of β-dicarbonyl compounds with aldehydes and urea or thiourea under acidic conditions [1]. However, most of the reported methods suffer from drawbacks such as harsh reaction conditions, use of harmful organic solvents, long reaction times, tedious work-up procedure, expensive and moisture-sensitive reagents, strongly acidic conditions [2-4]. Therefore, it is important to find more efficient conditions and methods for the synthesis of these compounds. Herein, we wish to report the new method for the synthesis of these compounds in the present of [SuSA-H]HSO4, as an efficient catalyst under mild reaction conditions (Scheme 1). Easy preparation of the catalyst, easy work-up procedure, excellent yields of products and short reaction times are some advantages of this work.