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[2,2'-Bipyrrolidine]-1,1'-disulfonic acid was easily prepared and recognized as a novel acidic catalyst through the reaction of 2,2'-bipyrrolidine with chlorosulfonic acid in CH2Cl2 at 0–5°C. The size and other properties of the prepared reagent were studied using FT-IR, 1H, 13C NMR, SEM, and also TGA analysis. After structural studies the efficiency of this reagent in the preparation of bis-triazoloquinazolinone derivatives via five-component one-pot reaction between bis-aldehydes, β-diketones and 3-amino-1,2,4-triazole was investigated. Operational simpleness, high yields, short reaction times and wide applicability are the key features of this methodology. All new products were characterized by using FT-IR, 1H, 13C NMR spectroscopy and elemental analyses. [ABSTRACT FROM AUTHOR]

A novel series of bis(tetrahydro[1,2,4]triazolo[5,1- b]quinazolin-8(4 H)-ones) were prepared in a regioselective manner via a three component reaction of bis-aldehydes with 5-amino-1,2,4-triazole and dimedone under microwave irradiation as well as under conventional heating. The reactions were carried out in the absence as well as in the presence of ZnO nanoparticles as a heterogeneous catalyst. Best results were achieved when these reactions were carried out under MW heating. The presence of ZnO nanoparticles was found to improve the yields of the reactions but did not change the regioselectivity the products. The reaction mechanism and the unambiguous structural elucidation of the expected regioisomers were studied using DFT calculations as well as 2D-HMBC spectroscopy. Graphical abstract: [ABSTRACT FROM AUTHOR]