A practical and highly efficient procedure for the selective preparation of 6,6a-dihydroisoindolo[2,1-a]quinazoline-5,11-diones through a palladium-catalyzed one-pot three-component cascade reaction of 2-aminobenzamides with 2-bromobenzaldehydes and carbon monoxide under atmospheric pressure has been developed. This cascade reaction, in which four new C–C/C–N bonds and two new rings are simultaneously constructed, is triggered by a cyclocondensation of 2-aminobenzamides with 2-bromobenzaldehydes, followed by a Pd-catalyzed cyclocarbonylation of the in situ formed 2,3-dihydroquinazolin-4(1H)-ones with CO (1 atm). Compared with the existing methods, the present protocol has the advantages of readily available starting materials, broad substrate scope, structural diversity of products, and free of high-pressure equipment.

An efficient and facile protocol for the synthesis of quinazolinone-fused tetracyclic compounds through an iodine-mediated one-pot cascade reaction of 2′-bromoacetophenones with 2-aminobenzohydrazides or 2-aminobenzamides is reported. With 2-aminobenzohydrazides as the substrates, the reaction gave 5H-quinazolino[3,2-b]cinnoline-7,13-diones in moderate to good yields under metal-catalyst-free conditions. With 2-aminobenzamides as the substrates and CuBr as the catalyst, on the other hand, it afforded tryptanthrin derivatives with good efficiency. Mechanistically, the formation of the tetracyclic systems is initiated by iodination and oxidation of 2′-bromoacetophenones followed by a cascade procedure consisting of cyclocondensation, aromatization and intramolecular cyclization of the in situ formed 2-bromoarylglyoxals with 2-aminobenzohydrazides or 2-aminobenzamides, respectively.

A simple and practical procedure for the preparation of C5-(isoxazol-3-yl)-pyrimidine nucleosides through 1,3-dipolar cycloaddition of the in situ formed C5-nitrile oxide substituted pyrimidine nucleosides with various terminal alkynes is presented. Compared with literature procedures, this new method has advantageous features such as readily available and inexpensive starting materials, simple procedure without using expensive transition metal catalyst, and broad scope of substrates. By employing this method, 30 nucleoside analogues were prepared in moderate yields. Biological studies on these C5-(isoxazol-3-yl)-pyrimidine nucleosides showed that most of them exhibited significant in vitro antileishmanial activity.

Highly selective and convenient synthesis of indolo[1,2-c]quinazolines and 11H-indolo[3,2-c]quinolines through copper-catalyzed one-pot cascade reactions of 2-(2-bromoaryl)-1H-indoles with aldehydes and aqueous ammonia has been achieved. Notably, the regioselectivity was easily controlled by tuning the reaction conditions. Compared with literature methods, the present protocol features easily controlled selectivity, readily available starting materials, good functional group tolerance, and simple operation procedures.

An efficient and practical procedure for the preparation of 2-substituted and 2,3-disubstituted quinazolinones was achieved through copper-catalyzed tandem reaction of 2-bromobenzamides with aldehydes and aqueous ammonia under air. Control experimental results indicated that this tandem reaction is triggered by a copper-catalyzed direct amination of 2-bromobenzamides with aqueous ammonia, followed by cyclocondensation and oxidative aromatization. As an application, this novel methodology provides a concise and practical one-pot route to the synthesis of alkaloid tryptanthrin.

A practical and efficient synthesis of pyrazolo[1,5-c]quinazolines and 5,6-dihydropyrazolo[1,5-c]quinazolines, including several spiro compounds, through copper-catalyzed tandem reaction of 5-(2-bromoaryl)-1H-pyrazoles with carbonyl compounds and aqueous ammonia under air has been developed. Compared with literature methods toward pyrazolo[1,5-c]quinazoline derivatives, the synthetic method reported in this paper has the advantages of readily available and inexpensive starting materials and reagents, broad scope of substrates, and mild reaction conditions.

An efficient procedure for the synthesis of 3,5-disubstituted pyrazoles has been achieved through cyclocondensation reaction of 1,2-allenic ketones and hydrazines under extremely mild conditions. As an application, this methodology provides a highly efficient route to 5-(5-methyl-pyrazol-3-yl)-2′-deoxycytidine.

An efficient and facile protocol for the synthesis of quinazolinone-fused tetracyclic compounds through an iodine-mediated one-pot cascade reaction of 2′-bromoacetophenones with 2-aminobenzohydrazides or 2-aminobenzamides is reported. With 2-aminobenzohydrazides as the substrates, the reaction gave 5H-quinazolino[3,2-b]cinnoline-7,13-diones in moderate to good yields under metal-catalyst-free conditions. With 2-aminobenzamides as the substrates and CuBr as the catalyst, on the other hand, it afforded tryptanthrin derivatives with good efficiency. Mechanistically, the formation of the tetracyclic systems is initiated by iodination and oxidation of 2′-bromoacetophenones followed by a cascade procedure consisting of cyclocondensation, aromatization and intramolecular cyclization of the in situ formed 2-bromoarylglyoxals with 2-aminobenzohydrazides or 2-aminobenzamides, respectively.

A practical and highly efficient procedure for the selective preparation of 6,6a-dihydroisoindolo[2,1-a]quinazoline-5,11-diones through a palladium-catalyzed one-pot three-component cascade reaction of 2-aminobenzamides with 2-bromobenzaldehydes and carbon monoxide under atmospheric pressure has been developed. This cascade reaction, in which four new C–C/C–N bonds and two new rings are simultaneously constructed, is triggered by a cyclocondensation of 2-aminobenzamides with 2-bromobenzaldehydes, followed by a Pd-catalyzed cyclocarbonylation of the in situ formed 2,3-dihydroquinazolin-4(1H)-ones with CO (1 atm). Compared with the existing methods, the present protocol has the advantages of readily available starting materials, broad substrate scope, structural diversity of products, and free of high-pressure equipment.