Microwave-Assisted Cobalt-Catalyzed Synthesis of Quinazolinones via Acceptorless Dehydrogenative Coupling under Neat...

Herein, we present a sustainable and atom-economical approach for the synthesis of quinazolinones via acceptorless dehydrogenative coupling (ADC) using earth-abundant Co-salt, (CoCl₂) as the catalyst under neat condition. This method is distinguished by its green credentials, like, solvent-free, microwave-assisted heating, cost-effective, use of renewable alcohols, and generating only H₂ and water as byproducts. Remarkably, this protocol achieves quinazolinone synthesis without the need for external ligands, oxidants, or additional additives. Two synthetic pathways were developed: one involving the coupling of alcohols with 2-aminobenzamide, and the other with N-phenyl-substituted 2-aminobenzamides and its derivative. The scalability of this method, demonstrated through gram-scale synthesis, highlights its potential for industrial applications. Mechanistic insights were explored through control experiments, intermediate detection by HRMS, and Hammett analysis, shedding light on the plausible reaction pathway.