Tetrahedron

A simple approach to pyrazol-3-ones via diazenes

B Burja, M Kočevar, S Polanc

Index: Burja, Bojan; Kocevar, Marijan; Polanc, Slovenko Tetrahedron, 2009 , vol. 65, # 42 p. 8690 - 8696

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Citation Number: 14

Abstract

An efficient entry into pyrazol-3-ones is described starting from propenoic acids that were first transformed into the corresponding hydrazides. Oxidation of the hydrazides gave the diazenes and the latter cyclized to pyrazol-3-ones on treatment with ZrCl4. The methoxycarbonyl protection of the N-1 of the pyrazolone derivatives was easily removed under mild reaction conditions.