Synthesis of Aromatic Heterocycles

Synthesis of Pyrazole

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Reaction of a 1,3-diketone and hydrazine gives a five-membered heterocycle known as a pyrazole. The enamine and imine formed make the heterocycle aromatic without having to carry out an oxidation step.

A. R. Katritzky, D. L. Ostercamp and T. I. Yousaf, Tetrahedron, 1987, 43, 5171–5186.