C-NMR spectroscopy of tropane alkaloids.

The natural abundance 13C-NMR spectra of tropine, atropine, scopolamine, cocaine, atropine methonitrate, and dl-tropic acid were determined at 22.63 MHz. With the aid of proton decoupling techiniques and by comparison with analogous simpler compounds, it was possible to make self-consistent and unambiquous assignments of all carbon resonances for these alkaloids. Some important chemical shift trends were observed and should be useful in the identification of similar systems.