Complete1H and13C NMR Chemical Shift Assignments for Some Pentacyclic Oxindole Alkaloids

Abstract
The complete analysis of the 1H and 13C NMR has been performed for four pentacyclic oxindole alkaloids: mitraphylline, isomitraphylline, speciophylline and pteropodine. The total assignment of the 1H NMR parameters was achieved from combined evaluation of homonuclear shift correlation and J-resolved diagrams, while DEPT spectra and selective decoupling experiments provided all carbon chemical shifts.