Peter L. Johnson, N. R. Pearson, B. Schuster
Jul 1, 2009
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0
Influential Citations
4
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Journal
Journal of Labelled Compounds and Radiopharmaceuticals
Abstract
Pentachloropyridine serves as a key intermediate in the synthesis of 4-amino-3,5,6-trichloropicolinic acid (picloram) and 4-amino-3,6-dichloropicolinic acid (aminopyralid). An M+3 stable isotope of pentachloropyridine (1, pentachloropyridine-1-15N-2,6-13C2) was prepared from K13C15N. Isotopically labeled pentachloropyridine was then carried through a seven-step synthesis to give an M+3 stable isotope of 4-amino-3,5,6-trichloropicolinic acid (2, picloram-1-15N-2,6-13C2) in an overall yield of 42%. The chlorine atom in the 5-position of 2 was selectively removed via electrochemical reduction. Carrying out the electrochemical reduction in water provided an M+3 stable isotope of 4-amino-3,6-dichloropicolinic acid (3, aminopyralid-1-15N-2,6-13C2), whereas conducting the reduction in deuterium oxide produced an M+4 stable isotope (4, aminopyralid-1-15N-2,6-13C2-5-2H). Copyright © 2009 John Wiley & Sons, Ltd.