Transition-Metal-Free Dehydrogenation of Benzyl Alcohol for C-C and C-N Bond Formation for the Synthesis of Pyrazolo[3,4- b ]pyridine and Pyrazoline Derivatives.

A series of cascade reactions that produce a range of functionalized aromatic heterocyclic compounds with pyrazole/pyrazoline cores have been developed. The method relies on a metal-free dehydrogenative process to produce in-situ benzaldehydes. The produced benzaldehyde was then allowed to react with some other substances, including acetophenone, pyrazole amine, and phenylhydrazine. The intermediate produced from these substrates underwent several chemical processes, including electrocyclization, the aza-Diels-Alder reaction, and the formation of intramolecular C-N bonds. These positive outcomes would open up the possibility of producing biologically active pyrazolo[3,4- b ]pyridine and pyrazoline derivatives through a variety of possible reactions.