Interconversion of ephedrine and pseudoephedrine during chemical derivatization (pages 1028–1033)
Colton H. F. Wong, Emmie N. M. Ho, W. H. Kwok, David K. K. Leung, Gary N. W. Leung, Francis P. W. Tang, April S. Y. Wong, Jenny K. Y. Wong, Nola H. Yu and Terence S. M. Wan
Article first published online: 26 JUN 2012 | DOI: 10.1002/dta.1384
Diastereoisomeric interconversion between ephedrine and pseudoephedrine was observed after derivatisation with fluorinated acylating agents (e.g. heptafluorobutyric anhydride, pentafluoropropionic anhydride and trifluoroacetic anhydride). The extent of conversion appeared to increase with the degree of fluorination of the acylating agent, and a mechanism of the interconversion was proposed. These findings show that fluorinated acylating agents should not be used for the unequivocal identification or quantification of ephedrine and pseudoephedrine as the results obtained can be erroneous.