Investigation of the alkaloids of Delphinium delavayi Franch var. pogonanthum (H-M) Wang has led to the isolation of nine known alkaloids and a new pair of regioisomeric alkaloids delavaine A (10A) and delavaine B (10B) whose structures have been determined based on spectroscopic evidence and two syntheses from methyllycaconitine (3). The known alkaloids that were isolated are the C19-diterpenoid alkaloids: deltaline (1), deltamine (2), methyllycaconitine (3), anthranoyllycaconitine (4), lycoctonine (5), delsemine (6), and the C20-diterpenoid alkaloids: hetisinone (7), hetisine (8), and ajaconine (9). Delsemine (6) has been synthesized from methyllycaconitine and chromatographically separated into its component regioisomers 6A and 6B. © 1986.