Synthesis of 3-Aryl-Substituted 4-Aminopyrazoles from Acetophenones

Abstract

A synthetic methodology for a protecting-group-free formation of 3-aryl-substituted 4-aminopyrazoles from acetophenones via a telescoped oximation and hydrazine condensation of 1,3-ketoaldehydes to generate nitrosopyrazoles, and copper-catalyzed NaBH₄ reduction of the nitroso group, was demonstrated. The synthesis tolerates a broad scope of substrates with a variety of substituents on the phenyl ring to afford the desired products.

Key words

3-aryl-substituted 4-aminopyrazoles - oximation - 1,3-dielectrophile condensation - nitroso reduction - heterocycles

• References

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