4-Formylpyrazoles: Applications in Organic Synthesis

4-Formylpyrazoles are useful building blocks in organic synthesis. This review focuses on the applications of 4-formylpyrazoles to generate a large variety of organic compounds and heterocycles such as Schiff bases, pyrazolylpyrazolines, pyrazoloquinolinones, 4H-pyrazolopyran, pyrazolylbenzoxazole, pyrazolothiadiazepines, pyrazolyloxazolone, pyrazolyloxadiazolines, pyrazolylthiadiazolines, imidazolylpyrazoles, pyrazolopyridines, chromenopyrazolones, thiopyranothiazolylpyrazoles and many others. Many of these molecules exhibit excellent biological activities.