Abstract
The urinary radioactivity excreted by dogs and rats administered 1C-labeled 2-hydroxynicotinic acid was mostly accounted for by unchanged drug and one metabolite. The metabolite was isolated in crystalline form and was identified as the N-riboside, 1,2-dihydro-1-β-D-ribofuranosyl-2-oxonicotinic acid. The identity of this metabolite. suggested first by interpretation of the nuclear magnetic resonance spectrum. was consistent with microchemical analysis and the spectra obtained by combined gas chromatography-mass spectrometry of a trimethylsilyl derivative. Final confirmation of the structure was obtained by chemical synthesis of the metabolite and the demonstration that the isolated and synthesized products were identical. N-riboside formation is an uncommon pathway of drug metabolism which appears to be limited to foreign compounds that are close analogs of those natural compounds. e.g., nicotinic acid and purine and pyrimidine bases, for which biosynthetic pathways for nucleoside and/or nucleotide formation do exist.
Footnotes
- Received November 20, 1972.
- Copyright © 1973 by The American Society for Pharmacology and Experimental Therapeutics
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