Copper-Catalyzed Synthesis of 1,2,4-Benzothiadiazine 1,1-Dioxide Derivatives by Coupling of 2-Halobenzenesulfonamides with Amidines

One-pot Tandem Synthesis and Spontaneous Product Separation of N-heterocycles based on Bifunctional Small-molecule Photocatalyst

Homogeneous and heterogeneous reactions wherein the resulting products remain dissolved in solvents generally require complicated separation and purification process, despite the advantage of heterogeneous systems allowing retrieval of catalysts. Herein, we have developed an efficient approach for the one-pot tandem synthesis of quinazolines, quinazolinones and benzothiadiazine 1,1-dioxides from alcohols and amines utilizing a bifunctional bipyridinium photocatalyst with redox and Lewis acid sites using air as an oxidant. Through solvent-modulation strategy, the photocatalytic system exhibits high performance and enables most products to separate spontaneously. Consequently, the homogeneous catalyst can be reused by direct centrifugation isolation of the products. Notably, the method is also applicable to the less active substrates, such as heterocyclic alcohols and aliphatic alcohols, and thus provides an efficient and environmentally friendly photocatalytic route with spontaneous separation of N-heterocycles to reduce production costs and meet the needs of atomic economy and green chemistry.

Copper-catalyzed synthesis of 2-aminopyridylbenzoxazoles via domino reactions of intermolecular N-arylation and intramolecular O-arylation

A simple and general approach to nitrogen-containing heterocycles via copper-catalyzed domino reaction has been developed, and the corresponding 2-aminopyridylbenzoxazole derivatives were obtained in good to excellent yields using the readily available starting materials. This method possesses unique step economy features, and is of high tolerance towards various functional groups in the substrates.

An Ullmann N-arylation/2-amidation cascade by self-relay copper catalysis: one-pot synthesis of indolo[1,2-a]quinazolinones

We have developed a self-relay copper(i)-catalyzed Ullmann N-arylation/2-amidation cascade to form functionalized indolo[1,2-a]quinazolinones in one-pot from easily available indoles with 2-bromobenzamides.

Iodine-mediated synthesis of 3-acylbenzothiadiazine 1,1-dioxides

An iodine-mediated synthesis of 3-acylbenzothiadizine 1,1-dioxides is described. A range of electronically diverse acetophenones reacted well with several 2-aminobenzenesulfonamides, affording 3-acylbenzothiadiazine 1,1-dioxides in good yields.

Copper-catalyzed domino synthesis of nitrogen heterocycle-fused benzoimidazole and 1,2,4-benzothiadiazine 1,1-dioxide derivatives

A convenient copper-catalyzed domino method for the synthesis of nitrogen heterocycle-fused benzoimidazole and 1,2,4-benzothiadiazine 1,1-dioxides has been developed using readily available 2-bromo-N-phenylbenzenesulfonamides and benzimidazole derivatives as the starting materials. The domino process comprises an Ullmann-type N-arylation and intramolecular C-H amination. The inexpensive and efficient copper-catalyzed method should provide a new and useful strategy for for constructing novel, biologically interesting heterocycles containing benzoimidazole and 1,2,4-benzothiadiazine 1,1-dioxide motifs.

Facile synthesis of benzothiadiazine 1,1-dioxides, a precursor of RSV inhibitors, by tandem amidation/intramolecular aza-Wittig reaction

Reaction of o-azidobenzenesulfonamides with ethyl carbonochloridate afforded the corresponding amide derivatives, which gave 3-ethoxy-1,2,4-benzothiadiazine 1,1-dioxides through an intramolecular aza-Wittig reaction. The reaction was found to be general through the synthesis of a number of benzothiadiazine 1,1-dioxides. Acid-catalyzed hydrolysis of 3-ethoxy-1,2,4-benzothiadiazine 1,1-dioxides furnished the 2-substituted benzothiadiazine-3-one 1,1-dioxides in good yields and high purity, which is the core moiety of RSV inhibitors.

Palladium-catalyzed N-monoarylation of amidines and a one-pot synthesis of quinazoline derivatives

A method for the Pd-catalyzed N-arylation of both aryl and alkyl amidines with a wide range of aryl bromides, chlorides, and triflates is described. The reactions proceed in short reaction times and with excellent selectivity for monoarylation. A one-pot synthesis of quinazoline derivatives, via addition of an aldehyde to the crude reaction mixture following Pd-catalyzed N-arylation, is also demonstrated.

Amino acids as the nitrogen-containing motifs in copper-catalyzed domino synthesis of N-heterocycles

A copper-catalyzed domino method for synthesis of quinazolinones has been developed using readily available α-amino acids as the nitrogen-containing motifs. The domino process underwent Ullmann-type N-arylation, decarboxylation, aerobic oxidation, and intramolecular addition. This method should provide a new and useful strategy for construction of N-heterocycles.

Concise copper-catalyzed one-pot tandem synthesis of benzimidazo[1,2-b]isoquinolin-11-one derivatives

A simple and efficient copper-catalyzed one-pot tandem method has been developed for synthesis of benzimidazo[1,2-b]isoquinolin-11-one derivatives via reactions of substituted 2-halo-N-(2-halophenyl)benzamides with alkyl 2-cyanoacetates or malononitrile under mild conditions.