Cyclization Reaction of α-Hydroxyketones with Anthranilamides or 2-Aminobenzenesulfonamides for the Synthesis of Quinazolinones and Benzothiadiazines

We report in this research a novel and practical way for synthesizing quinazolin-4-(3<i>H</i>)-ones and the structural analogues (34 derivatives) and 1,2,4-(2<i>H)</i>-benzothiadiazine-1,1-dioxides (6 derivatives) using various α-hydroxyketones and anthranilamides or 2-aminobenzenesulfonamides as substrates with yields up to 96%. The method features cheap additives (only I₂ as a catalyst or I₂ and Fe³⁺ as catalysts and KMnO₄ as an oxidant), easy operation, and high atom utilization and provides a straightforward protocol for the preparation of these components of significant pharmacological potential.