2,3-二羟基苯甲酰胺 、 methyl (2aR,6aR,8S,14bS)-2a-methoxy-5-oxo-1,2,2a,3,4,5,6,6a,8,9,14,14b-dodecahydroindolo[2',3':3,4]pyrido[1,2-a]quinoline-8-carboxylate 在
甲酸 、
silver(l) oxide 作用下,
以60%的产率得到methyl (2aR,6aR,8S,9aR,16aR,16bS)-11-hydroxy-2a-methoxy-5,15-dioxo-1,2a,3,4,5,6,6a,8,9,15,16,16b-dodecahydro-2H-16a,9a-(epimino[1,2]benzeno)benzo[6′,7′][1,4]oxazepino[3′,2′:3,4]pyrido-[1,2-a]quinoline-8-carboxylate