Synthesis of Enantiomerically Enriched <font>α</font>-Bromonitriles from Amino Acids
作者:Najeh Tka、Jamil Kraïem、Béchir Ben Hassine
DOI:10.1080/00397911.2011.608142
日期:2013.1.1
Two methods were investigated for the preparation of six chiral alpha-bromonitriles with different optic purities. The nitrous deamination of amino acids gives alpha-bromoacids, which react with chlorosulfonyl isocyanate followed by triethylamine to afford alpha-bromonitriles with moderate enantiomeric excess. However, the dehydration of corresponding alpha-bromoamids using thionyl chloride gives alpha-bromonitriles with good enantiomeric excess up to 94%. The use of phosphoryl chloride instead of thionyl chloride results in more than 30% racemization as determined by high-performance liquid chromatograpic analysis.