REEXAMINATION OF THE BROMINATION OF 2-NITROBENZALDEHYDE WITH NBS OR NaBr-NaIO4 IN SULFURIC ACID

Two literature procedures for selective bromination of 2-nitrobenzaldehyde using N-bromosuccinimide (NBS) or NaBr-NaIO4 in sulfuric acid were examined. In contrast to the reports that 4-bromo-2-nitrobenzaldehyde is formed as a single product in good yield, reactions using NBS gave a number of isomeric mono- and dibrominated products identified by spectroscopical methods and by sodium borohydride reduction to the corresponding benzyl alcohol, and reactions using NaBr-NaIO4 did not furnish any product. [Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications (R) for the following free supplemental resource(s): Full experimental and spectral details.]