Pyridinium hydrobromide perbromide induces ipsobromodeformylation in o-hydroxy and o-methoxy substituted aromatic aldehydes

R Córdoba, J Plumet

Index: Cordoba, Ruben; Plumet, Joaquin Tetrahedron Letters, 2002 , vol. 43, # 51 p. 9303 - 9305

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Citation Number: 8

Abstract

In this context, the bromination of 2-hydroxy-4-methoxybenzaldehyde 1 using PHPB (2.1 equiv., pyridine) has been reported to give the expected 3,5-dibromo-2-hydroxy-4-methoxybenzaldehyde 2 in 83% isolated yield 6 (Scheme 1). In our hand this experiment was well reproduced (80% isolated yield of 2). However, we have observed that the use of 3.5 equiv. of PHPB affords, under the same reaction conditions, a mixture of 2 and 2,4,6-tribromo-4-methoxyphenol 3 in a ...