Synthesis, Chemical Reactivities, and Biological Properties of Pyrazolone/ Pyrazolinone as a Blocking Unit for Building Various Heterobicyclic Systems: A Review

: This review reports various synthetic routes of pyrazolone/ pyrazolinone derivatives via the addition of cycloaddition, condensation, cyclocondensation, modification, alkylation, as well as formylation, regioselective, and ring-opening reactions under reflux, microwave irradiation, and/ or ultrasonication conditions. It also presents critical chemical behaviors towards nucleophilic and electrophilic reagents. The chemical reactivities of pyrazolone/ pyrazolinone derivatives involve alkylation, acylation, condensation, catalyzed diazo coupling, oxidation, heteroarylation, phosphorylation, stereoselective alkenylation, enantioselective alkylation, addition, and complexation reactions. The review also summarizes the significant biological activity of pyrazolone/ pyrazolinone derivatives as antibacterial, antifungal, anti-inflammatory, anticancer, antitumor, anthelmintic, analgesic, as well as antioxidant, anthelmintic, antibiofilm, and anti-HIV. Moreover, some pyrazolone/ pyrazolinone derivatives used to remove various metal or soft metal ions from the wastewater. Besides, they exhibited stable complexes with some metals, for example, Ag (I), Cu (I), Cu (II), Hg (II), Pb (II), Sn (II), and Sb (V) as new materials, catalysis, and precursors for CVD in the microelectronic industry and as potential antitumoral.