Copper(II)-Mediated Dual Reactivity of 2-(5-Phenylisoxazol-3-yl)aniline: Directed Amination and Oxidative C(═O)─C Cleavage of Amides Enabling Direct Access to Urea Derivatives.

The dual reactivity of amides fused to 2-(5-phenylisoxazol-3-yl)aniline as a directing group for the formation of urea derivatives via chemospecific cleavage of the C(═O)─C bond and C(sp)-H amination is reported here. Employing inexpensive copper as the catalyst and O in air as the oxidant, this protocol exhibited broad functional group tolerance for both the transformations. Detailed mechanistic studies and DFT calculations were performed to gain insights into a plausible mechanism for the formation of urea derivatives.

Synthesis of N-Fused Triazole-Piperazine-Quinazolinones via One-Pot Tandem Click Reaction and Cross-Dehydrogenative Coupling.

Herein, a one-pot protocol to synthesize tetracyclic triazole-piperazine-quinazolinone-fused N-heterocyclic scaffolds is reported. In this strategy, a tandem approach of two highly efficient synthetic reactions, click and cross-dehydrogentive coupling reactions, with high atom economy were employed to obtain the target N-fused scaffolds. Being highly functional group tolerable, this method has broad substrate scope.

Cu-Catalyzed Direct Diversification of 2-(2-Bromophenyl)quinazolin-4(3)-ones through Orthogonal Reactivity Modulation.

A modular strategy to obtain three different products from a single substrate was developed. The present methodology unveils new step-economical and cost-efficient routes to access diverse fused quinazolinoquinazolinone derivatives which are not prevalent in literature. Owing to the importance of quinazolinones in therapeutics, quick access to the arena of these scaffolds could be a valuable addition to the scientific domain of heterocyclic chemistry.