Microwave Assisted Three Component One-pot Synthesis of Bis(aminoazolo[1,5-a]pyrimidines) and Bis(aminoazino[1,2-a]benzimidazoles) Bearing Thiazole Moiety

Novel bis[(thiazol-2-yl)acetonitrile] derivatives were prepared in good yields by the cyclocondensation of bis(bromoacetyl) derivatives with two equivalents of 2-cyanothioacetamide in dioxane at reflux. The bis[(thiazol-2-yl)acetonitrile] derivatives were taken as synthetic precursors for the synthesis of novel bis(aminoazolo[1,5-a]pyrimidines), bearing thiazole moiety. The target molecules were prepared by the three component one pot reaction of bis[(thiazol-2-yl)acetonitrile] derivatives, dimethylformamide-dimethylacetal and several of 3-aminopyrazoles in pyridine under microwave irradiation at 140 °C for 2 h. Using the same protocol, novel bis(aminotriazolo[1,5-a]pyrimidines), bis(aminopyrimido[1,2-a]benzimidazoles) and bis(aminopyrido[1,2-a]benzimidazoles), incorporating thiazole moieties, were prepared by using the appropriate heterocyclic amine or 2-(1H-benzoimidazol-2-yl)acetonitrile instead of 3-aminopyrazoles. The structure of the newly prepared thiazoles was confirmed via considering their elemental analyses and spectral data