New proaporphines found in Thai Stephania venosa include (+)-N-car-boxamidostepharine [2], (—)-O-methylstepharinosine {3}, and (—)-stepharinosine [5]. Alkaloid 2 is the first proaporphine incorporating a urea functionality, while 3 and 5 are the only proaporphines oxygenated at C-12. The plant also produces the new aporphines (—)-sukhodianine-β-N-oxide [6], (—)-ushinsunine-β-N-oxide [7], and (—)-stephadiolamine-β-N-oxide [8}. All three N-oxides are hydroxylated at C-7, but (—)-stephadiolamine-β-N-oxide [8] is also hydroxylated at C-4. Thus, this is the first aporphine hydroxylated at both of these sites; 17 known isoquinoline alkaloids were also obtained. © 1987, American Chemical Society. All rights reserved.