Migration of an acyl group in the pyrazole system: synthesis of 1-acyl-3-hydroxy-1 H-pyrazoles and related derivatives. A new preparation of N, N′-diacylhydrazines

…, F Požgan, A Golobič, S Polanc, M Kočevar

Index: Kepe, Vladimir; Pozgan, Franc; Golobic, Amalija; Polanc, Slovenko; Kocevar, Marijan Journal of the Chemical Society - Perkin Transactions 1, 1998 , # 17 p. 2813 - 2816

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Citation Number: 41

Abstract

A new general method for the synthesis of 1-acyl-3-hydroxy-1H-pyrazoles 5a–f and related derivatives 5g–i starting from 4-ethoxymethylene-2-phenyloxazol-5 (4H)-one (1) and hydrazides, 4-phenylsemicarbazide, 4-phenylthiosemicarbazide and benzyl carbazate in boiling dioxane is described. The method includes a migration of an acyl or related unit. The X-ray study and NMR spectroscopic examination confirmed the structure of the products. A ...