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A one-pot procedure for the synthesis of 5-benzoyl-8H-phthalazino[1,2-b]quinazolin-8-ones is achieved by an iodine-catalyzed reaction of 2-aminobenzohydrazides and 2-alkynylbenzaldehydes in good yields. The salient feature of this strategy is a domino type process including a condensation, addition, hydroamination, and a noteworthy benzyl automatic oxidation by oxygen under metal-catalyst-free conditions.

At 60 °C in DMSO, the iodine-catalyzed reaction of 3-aminopyrazine-2-carbohydrazide and 2-(arylethynyl)benzaldehydes led hydrazones. Increasing the reaction temperature to 100 °C, the amino and amido still indicated inactive, only the imine took part in the addition of acetylene bond to give 2-arylisoquinolines in high yields with the cleavage of N-N bond unexpectedly under metal-free conditions.

The Sonogashira reaction first, and then intra-molecular hydroamination of alkyne catalyzed by CuI/o-phen was proved to be an efficient method for the synthesis of imidazo[2,1-a]isoquinoline, phenanthro[9′,10′:4,5]imidazo[2,1-a]isoquinoline and acenaphtho[1′,2′:4,5]imidazo [2,1-a]isoquinoline derivatives in the presence of Cs2CO3.

2,3-Bisaryldiimidazo [1,2-a:1′,2′-c]quinazolines were obtained via a copper-catalyzed reaction between 2-(2-bromophenyl)-4,5-diphenyl-1H-imidazole and 2-bromo-1H- imidazole in good yields. This double Ullmann cross-coupling built two new Csp2-N bonds and fused tetracyclic heterocycle bearing four nitrogen atoms in one-pot procedure.

The domino reaction of 4-halogenated isatins and 2-amino-N′-arylbenzohydrazides catalyzed by CuI in the presence of Cs2CO3 is described. A possible reaction mechanism containing the consecutive condensation, cyclization, C–N bond Ullmann coupling, ring-opening and decarboxylation is put forward according to the control experiments. This procedure provides an efficient method for the synthesis of fused polycyclic 1-amino-5-arylindazolo[3,2-b]quinazolin-7(5H)-ones derivatives in good yields.

The benzyl position was found to be automatically oxidized by oxygen in the reaction of 2-(2-bromophenyl)-1H-imidazole and 1,3-dicarbonyl compounds catalyzed CuI. This domino procedure involved the subsequent α-arylation, deacylation, nucleophilic addition and benzyl automatic oxidation, and provided an efficient method for the synthesis of (benzo)imidazo[2,1-a]isoquinolinone derivatives in good yields.

The Ullmann cross-coupling reaction between 2-(2-bromophenyl)-4,5-diphenyl-1H-imidazole and 2-bromobenzenethiol occurred to give 2,3-diaryldibenzo[b,f]imidazo[1,2-d] [1,4]thiazepines in good yields. Two new bonds of Csp2-N and Csp2-S were built under the same catalytic system of CuI/o-phen in the presence of K2CO3.

A Domino reaction of 2-aminobenzohydrazides and 2-bromocinnamaldehydes is treated in the presence of CuI and Cs 2 CO 3 , and gives unexpected pyrazolo[5,1- b ]quinazolin-9(1 H )-one derivatives in good yields. A possible mechanism containing subsequent Michael addition and elimination is proposed to explain the formation of the pyrazole ring. This new procedure has the advantages of one-pot, available reactant, and milder conditions.

A three-component reaction of 2-halogenated aromatic aldehydes, 1H-benzo[d]imidazol-5-amine and cyclohexane-1,3-diones is described, and gives imidazoquinolinoacridinone derivatives in good yields catalyzed by CuI/ l -proline. This Domino reaction constructs a fused hexacyclic skeleton in one-pot containing two new rings, six new bonds and an Ullmann-type C–N bond coupling reaction.

The domino reaction of (E)-2-amino-N′-(1-arylethylidene)benzohydrazide and triethyl orthoformate in ionic liquids catalyzed by 10 mol % iodine gave 3a,4-dihydro-2-arylpyrazolo[5,1-b]quinazolin-9(3H)-one derivatives unexpectedly. In the presence of K2S2O8, it could be oxidized to aromatized products in good yields.

The 1-arylpyrazolo[5,1- b ]quinazolin-9(1 H )-one derivatives were obtained via intramolecular alkyne hydroamination reaction of 2-amino- N ′-arylbenzohydrazide and alkynal diethyl acetal in the presence of CuBr and Cs 2 CO 3 . This new procedure provides an efficient method to construct fused tricyclic heterocycle containing both pyrazole and quinazoline analogues.

A three-component reaction of aromatic aldehyde, naphthalene-2-amine, and tetrahydro-2,5-dimethoxyfuran in methanol catalyzed by iodine, is described in this paper. With the ring-opening of furan, a series of 3-aryl-2-(3-arylbenzo[f]quinolin-2-yl)benzo[f]quinoline derivatives were obtained in moderate yields.

A facile synthetic method using low-valent titanium reagent (TiCl 4 /Zn system) to promote the novel reductive cyclization of 2-nitrobenzamides and triphosgene is described. Sequentially, a series of quinazoline-2,4-diones were synthesized in good yields.