NMR Analysis of tautomerisms of active pinacidil-Type potassium channel openers and a less active one

In order to clarify the structural difference between active pinacidil-type potassium channel openers and a less active one, the tautomerisms of pinacidil derivatives Figure 1 and Figure 10 were investigated by NMR spectrometries. The predominant tautomer of the less active compound Figure 1 and Figure 10 was different from those of the active compounds Figure 1 and Figure 10 and Figure 1 and Figure 10.