Iron(III) phthalocyanine chloride-catalyzed oxidation–aromatization of α,β-unsaturated ketones with hydrazine hydrate: Synthesis of 3,5-disubstituted 1H-pyrazoles

We have developed an iron(III) phthalocyanine chloride-catalyzed oxidation–aromatization of α,β-unsaturated ketones with hydrazine hydrate. Various 3,5-disubstituted 1H-pyrazoles were obtained in good to excellent yields. This method offers several advantages, including room-temperature conditions, short reaction time, high yields, simple work-up procedure, and use of air as an oxidant. The catalyst can be recovered and reused five times without loss of activity.

Graphical AbstractIron(III) phthalocyanine chloride-catalyzed oxidation–aromatization of α,β-unsaturated ketones with hydrazine hydrate was achieved, to give 3,5-disubstituted 1H-pyrazoles under mild conditions. The catalyst was recycled five times without loss of activity.Figure optionsDownload as PowerPoint slide