Comparison of solution conformational preferences for the hallucinogens bufotenin and psilocin using 360-MHz proton NMR spectroscopy.
Journal of medicinal chemistry February 1, 1981 G P Migliaccio, T L Shieh, S R Byrn et al. 34 citations
NMR spectroscopy reveals that the side-chain conformations of bufotenin and psilocin differ in solution. In water, both compounds have similar populations of trans and gauche rotamers. In chloroform, bufotenin shows a slight preference for the trans rotamer, while psilocin strongly favors the gauche form, stabilized by about 1 kcal/mol, possibly due to a weak hydrogen bond. The difference in biological activity between the two compounds is largely explained by their different basicities: the amino group pKa of psilocin is 8.47, compared to 9.67 for bufotenin, which affects their partitioning behavior.