“…36 There are 12 alkaloids (39)(40)(41)(42)(43)(44)(45)(46)(47)(48)(49)(50) with an N-CHO formamide group formed from a C-21 aldehyde. 4,[38][39][40][41][42][43][44][45] Among these compounds, alkaloids 41-45 are DAs that have no oxygen-containing group at C-16. 4,39-41 N-Formyl-4,19secopacinine (51) 45 and N-formyl-4,19-secoyunnadelphinine (52) 38 from D. elatum contain another kind of formamide, which is formed from C-19 aldehydes.…”