Synthesis 2004(2): 283-289  
DOI: 10.1055/s-2003-44390
PAPER
© Georg Thieme Verlag Stuttgart · New York

Conversion of Benzal Halides to Benzaldehydes in the Presence of Aqueous Dimethylamine

Donald Bankston*
Bayer Pharmaceuticals Corporation, Department of Chemistry Research, West Haven, CT 06516, USA
e-Mail: donald.bankston.b@bayer.com;
Further Information

Publication History

Received 8 August 2003
Publication Date:
18 December 2003 (online)

Abstract

Aqueous dimethylamine is an efficient reagent for the conversion of a variety of benzal halides to their corresponding benz­aldehydes. Studies indicate that aqueous dimethylamine significantly accelerates aldehyde formation from benzal halide precursors, as compared to the use of water alone. Indeed, these reactions are routinely completed in one hour or less, depending upon substrate substitution. Desired products can be isolated in pure form, and in high yield, but silica gel filtration is often necessary to remove baseline contaminants. The method represents a novel, economical approach to acquire pure, substituted benzaldehydes from commercially available, or easily prepared starting materials.

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Note: These reactions were conducted at temperatures below 70 °C, which are not high enough to promote significant decomposition of DMF. Decomposition of DMF became relevant at temperatures around 140 °C.