Chemistry of α-Oxoesters: A Powerful Tool for the Synthesis of Heterocycles

Most heterocycles exhibit biological activity, including antitumor, anti-HIV, antibiotic, antidepressant, antiinflammatory, antiviral, antidiabetic, antimalarial, antimicrobial, antibacterial, antifungal, herbicidal, fungicidal, and insecticidal activities. Additionally, they have important applications in organic synthesis as organocatalysts, synthetic intermediates, chiral auxiliaries, and metal ligands in asymmetric catalysis. Therefore, the development of new efficient methods to synthesize heterocycles is of considerable interest. Pyrazole and pyrazoline derivatives have received great attention because of their interesting biological activities, such as antibacterial, antiviral, antidiabetic, antitubercular, antitumor, anti-inflammatory, and antidepressant activities.