Synthetic Routes to Bioactive Bipyrazole Derivatives

Abstract The synthetic routes to six differently connected bipyrazole systems 1,1′‐, 1,3′‐ and 1,4′‐, 3,3′‐, 3,4′‐ and 4,4′‐bipyrazoles are thoroughly reported. Two main synthetic platforms are outlined; i) cyclocondensation reactions of tetraketones or pyrazoles having difunctional moieties with hydrazines, or pyrazolyl‐hydrazines with difunctional substrates, ii) 1,3‐dipolar cycloaddition of nitrilimines with bis‐olefines, or bis‐nitrilimines with activated alkenes and alkynes. Many of the reported bipyrazoles have potent applications; in pharmaceutical and material science areas.