Expedited Route to Fully Substituted Amino-Pyrazole Building Blocks and Their Further Transformations.

Abstract

We report here an efficient and easily reproducible two-step approach to heterocycle-substituted amino-pyrazoles from heterocyclic acetonitriles and their unprecedented subsequent transformations to fully substituted pyrazoles. Such transformations include regioselective derivatization from polyamino derivatives, formation of tetracyclic compounds in up to 45% overall yield, and deaminative transformations through diazotization, followed by arylation through Suzuki–Miyaura cross-coupling and C–H activation, providing arylated pyrazoles in up to 71% yield over four steps. This strategy allows the swift introduction of significant molecular complexity to a range of scaffolds.