Kinetics and mechanism of oxime formation from pyruvic acid

The following lines of evidence establish that oxime formation from pyruvic acid occurs with rate-determining carbinolamine dehydration under acidic and neutral conditions. First, saturation effects observed at pH 7 are strongly suggestive of carbinolamine accumulation, requiring that dehydration of the intermediate be the rate-determining step. Second, the reaction occurs exclusively with general acid catalysis in the entire range investigated. The pH-rate plot shows a break at pH near 2, which can be interpreted in terms of protolytic equilibrium of the substrate. Copyright (C) 2000 John Wiley & Sons, Ltd.