Regiocontrolled 1,3-Dipolar cycloadditions of nitrile imines with acetylenes and α,β-unsaturated systems: Synthesis of polysubstituted and ring fused pyrazoles with pharmaceutical activity

1,3-Dipolar cycloadditions of nitrile imines with functionalised acetylenes and α,β-unsaturated systems of various sizes have been studied. After cycloaddition, mono- and ring-fused pyrazoles have been obtained. Computational studies allowed a theoretical description of the observed reactivity, in agreement with the experimentally observed regio-chemistry. Selected targeted structures for medicinal applications have been synthetized and in vitro cytotoxicity showed that these pyrazoles can be considered powerful lead compounds for further medicinally relevant targets development.