The isolation and structure elucidation by spectral and chemical methods is given for five new alkaloids from the roots of Thalictrum rochebrunianum. Four of these are related to thalibrunine (1) and are oxothalibrunimine (3), thalictrinine (4), dihydrothalictrinine (5) and IV'-northalibrunine (6); all have been interrelated with thalibrunimine (2). Oxothalibrunimine (3) was obtained by air oxidation of thalibrunimine (2) whereas thalictrinine (4) resulted when the oxidation was performed with Pd on C. NaBH4 reduction of thalictrinine (4) afforded dihydrothalictrinine (5), a sole product, thus suggesting steric control to the S alcohol. NaBH4 reduction of thalibrunimine (2) gave N-northalibrunine (6) and the C-l” epimer 7. Similar reduction of thalsimine (9) gave the corresponding dihydro products, JV'-norhernandezine (8), the isomer identical with the natural product, and N'-epinorhernandezine (10). © 1980, American Chemical Society. All rights reserved.