Three alkaloids, northalicarpine (1), thalflavidine (4) and A'-methyllaurotetanine (5) were isolated from the roots of T. revolutum. Northalicarpine (1), a new natural product, was characterized from spectral data and by conversion to thalicarpine (2). The location of the. Y-desmethyl position was proved by isolation of the phenolic isoquinoline base 3 after Na/NH3 cleavage. Thalflavidine (4) and N-methyllaurotetanine (5) were identified from analysis of spectral data. © 1980, American Chemical Society. All rights reserved.