Ruthenium-Catalyzed Synthesis of Quinazolinones through Hydrogen Transfer and Cyclization

Pd(II)-Catalyzed Cascade Annulation of o-Aminobenzoic Acids with CO, Amines, and Aldehydes to N3-/N1,N3-Substituted 2,3-Dihydroquinazolin-4(1H)-ones

The unprecedented Pd(II)-catalyzed cascade annulation of o-aminobenzoic acids with CO, amines, and aldehydes has been developed. This protocol provides an efficient and concise approach to selective construction of N3-substituted and N1,N3-disubstituted 2,3-dihydroquinazolin-4(1H)-ones mostly in moderate to excellent yields from simple and easily available starting materials under mild conditions featured with low cost, high step economy, broad substrate scope, and good product diversity.

Fast quinazolinone synthesis by combining enzymatic catalysis and photocatalysis

A fast and highly efficient method for the synthesis of functionalized quinazolinones by combining enzymatic catalysis and photocatalysis is reported. The α-Chymotrypsin catalyzed the cyclization of aldehyde and 2-aminobenzamide, which was subsequently followed by White LED-induced oxidation of 2-phenyl-2, 3-dihydroquinazolin-4(1H)-one to obtain quinazolinone. The reaction process was highly efficient with a reaction yield of 99% in just 2 h, and a wide range of quinazolinones could be synthesized. Furthermore, the plausible mechanism was investigated by control experiments and DFT calculations. This protocol provides an alternative synthetic route for the preparation of quinazolinone derivatives.

Unexpected Insertion of Nitrogen into a C-C Bond: Access to 2,3-Disubstituted Quinazolinone Scaffolds

A novel, practical, highly efficient, and transition metal free nitrogen insertion reaction for the synthesis of 2,3-disubstituted quinazolinone derivatives was developed. Diverse functionalized 3-indolinone-2-carboxylates and nitrosoarenes with a wide range of substituted nitrosobenzenes, nitrosopyridines, dibenzofuranyl, or dibenzothienyl nitroso compounds worked smoothly to give 2,3-disubstituted quinazolinone derivatives in good to excellent yields (69-98%). A gram-scale reaction was achieved, and an afloqualone analogue was synthesized under the mild reaction conditions.

Ruthenium-catalysed chemoselective alkylation of nitroarenes with alkanols

The alkylation of nitroarenes with akanols catalysed by the phosphinesulfonate ruthenium complex was reported. It displays different reactivity and chemoselectivity depending on the acid–base conditions, delivering diverse anilines from nitroarenes.