Computer-assisted structural elucidation. Alkaloids with a novel diaza-adamantane skeleton from the seeds of Acosmium panamense (Fabaceae).

Three alkaloids, acosmine 1, acosmine acetate 2 and panacosmine 3 with a no vel diazaadamantane skeleton and an unusual N-acetyl enamine moiety, have b een isolated from the seeds of Acosmium panamense (Benth.). The structures were assembled on the basis or COSY, HMQC and HMBC data with the assistance of the LSD structure elucidation program. Proton-nitrogen HMBC experiments support the proposed structures. Other isolated compounds include 4 alpha- angeloyloxy-3 beta-hydroxy-13 beta-methoxylupanine 4, a new compound and th e known alkaloids lupanine and multiflorine. (C) 1999 Elsevier Science Ltd. All rights reserved.