One-Pot Copper(I)-Catalyzed Ligand/Base-Free Tandem Cyclooxidative Synthesis of Quinazolinones

Abstract

A novel and efficient Cu(I)-catalyzed ligand- and base-free multipathway domino strategy has been developed for the synthesis of 2-substituted quinazolinones. The reaction utilizes 2-bromobenzamide and multiform substrates such as aldehydes, alcohols, and methyl arenes for a one-pot protocol, whereas TMSN3 is used as a nitrogen source. A wide range of substrate scope, functional group tolerance, and operational simplicity are synthetically useful features.

The Synthesis of Quinazolinones from Olefins, CO, and Amines over a Heterogeneous Ru‐clusters/Ceria Catalyst

“…However, these methods generally suffer from drawbacks such as complex homogeneous catalytic systems or expensive feedstocks. Recent examples of oxidative condensation reactions of alcohols, methyl arenes, and amines often require excess amounts of oxidants (Scheme a, route 2). Wu et al.…”

“…From consideration of the high selectivity in the synthesis of 3 with the Ru‐clusters/ceria catalytic system (Table , entry 7), we proposed the remaining new signals at 171.9, 171.5, 139.1, 133.7, 132.2, 126.5, 121.5, 120.4, 30.5, and 8.6 ppm probably arose from a reaction intermediate. The signals at 30.5 and 8.6 ppm were assigned to the chemical shift of C atoms of an ethyl group and the signals at 139.1, 133.7, 132.2, 126.5, 121.5, and 120.4 ppm to the chemical shifts of C atoms of a benzene ring . Two signals at 171.9 and 171.5 ppm were assigned to the chemical shift of C atoms of the carbonyl groups .…”

Copper‐Catalyzed Self‐Condensation of Benzamide: Domino Reactions towards Quinazolinones

“…Due to its broad synthetic and medicinal applications of these molecules, there has been much effort directed towards their synthesis. [10,12,13] Despite these advances, it has been a challenge to synthesize highly functionalized quinazolinones from easily accessible starting materials and by employing green chemistry techniques. However, the catalytic approach offers numerous synthetic benefits over classical approach [11] which includes; shorter reaction times, extended scope and reduced tained in one-pot reaction by intramolecular cyclization (condensation) via Ullmann-type intermediate.…”

The Synthesis of Quinazolinones from Olefins, CO, and Amines over a Heterogeneous Ru‐clusters/Ceria Catalyst

“…[2] However,t hese methods generally suffer from drawbacks such as complex homogeneous catalytic systems or expensive feedstocks. Recent examples of oxidative condensation reactions of alcohols, [3] methyl arenes, [4] and amines [5] often require excess amounts of oxidants (Scheme 1a,r oute 2). Wu et al reported ap alladium-catalyzed carbonylation reaction to synthesize quinazolinones from o-aminobenzamides,b romobenzenes,and carbon monoxide (CO;Scheme 1a,route 3).…”

“…[2a] Tw os ignals at 171.9 and 171.5 ppm were assigned to the chemical shift of Ca toms of the carbonyl groups. [16] On the basis of these assignments,weconcluded that the reaction intermediate was probably an amide species (4), which was generated by carbonylation of the NH 2 group connected directly to the benzene ring. Theg eneration of an amide species as an intermediate in the reaction was verified from the time course of the synthesis of 3 over the Ru-clusters/ceria catalyst ( Figure S3).…”