A reassignment of the 13C‐NMR spectrum of the alkaloid ajmaline through the use of two‐dimensional nmr techniques

Abstract

The reassignment of the ¹³C chemical nmr spectrum of the alkaloid, ajmaline, is reported. An earlier assignment based on analogy to other alkaloids and deductions from molecular orbital theory was found to be partially in error. The present study uses broadband decoupled (both dimensions) proton‐carbon shift correlation and long‐range proton‐carbon chemical shift correlation techniques. These experiments, in conjunction with earlier work by others on the assignment of the proton spectra, suffice to now unequivocably assign the ¹³C nmr spectrum of the title compound.