Rapid identification of ergot derivatives by 1H-NMR spectroscopy.

The 400 MHz 1H-NMR spectra of some therapeutically important ergot derivatives (three bases, four protonated bases and four dihydroergoline salts) are analysed in terms of the low field chemical shift region (above 5 ppm), common resonances of rings C and D (below 5 ppm) and C-8 substituent features. Attention is drawn to data of specific analytical value, and a scheme for the rapid identification of members of this group of ergots proposed. Features which provide evidence of the solute conformation of ring D, and isomerization to less active C-8 epimers are also emphasized.