A series of vallesamine-type alkaloids was isolated from Alstonia angustiloba and Alstonia pneumatophora. Besides the known alkaloids vallesamine [1] and O-acetylval-lesamine [2], the following new alkaloids were found: angustilobine A [3], 15-hydroxy-angus-tilobine A [5], angustilobine B [4], 4,6-secoangustilobinal [6], 6,7-seco-19,20-epoxyangustilobine B [7], 6,7-seco-6-cyanostemmadenine [8], 6,7-secoangustilobine B [9], and nor-6,7-secoangustilobine A [10]. The structures are based on the spectral data of these alkaloids. © 1987, American Chemical Society. All rights reserved.