A novel synthesis of new 2-aryl-6-(arylamino)-1H-imidazo[1,2-b]pyrazole-7-carbonitrile derivatives

Selective functionalization of the 1H-imidazo[1,2-b]pyrazole scaffold. A new potential non-classical isostere of indole and a precursor of push-pull dyes

We report the selective functionalization of the 1H-imidazo[1,2-b]pyrazole scaffold using a Br/Mg-exchange, as well as regioselective magnesiations and zincations with TMP-bases (TMP = 2,2,6,6-tetramethylpiperidyl), followed by trapping reactions with various electrophiles. In addition, we report a fragmentation of the pyrazole ring, giving access to push-pull dyes with a proaromatic (1,3-dihydro-2H-imidazol-2-ylidene)malononitrile core. These functionalization methods were used in the synthesis of an isostere of the indolyl drug pruvanserin. Comparative assays between the original drug and the isostere showed that a substitution of the indole ring with a 1H-imidazo[1,2-b]pyrazole results in a significantly improved solubility in aqueous media.

Synthesis of novel series of 7,7′-(substituted methylene)bis-imidazo[1,2-b]pyrazoles via an acid catalyzed one-pot three-component reaction

An efficient and rapid synthesis of new series of N-alkyl-2-aryl-5H-imidazo[1,2-b]pyrazoles has been achieved in high yields through a three-component reaction of 3-amino-4-substituted pyrazoles, aromatic aldehydes and isocyanides mediated by acid catalysts.

Graphene oxide–TiO2 composite: an efficient heterogeneous catalyst for the green synthesis of pyrazoles and pyridines

GO–TiO₂ has been found to be a highly efficient and recyclable heterogeneous catalyst for the synthesis of pyrazoles and pyridines in aqueous medium at room temperature.