Four minor alkaloids of L. annotinum have been examined by chemical methods and infrared spectroscopy for their functional groups. Acrifoline (L.27) C16H23O2N has a double bond, a carbonyl group, and an hydroxyl function. Annotine (L.11) C16H21O3N has a double bond, a carbonyl group, an hydroxyl function, and an inert oxygen probably present in an ether linkage. Alkaloid L.12 (C18H25O3N) is O-acetylacrifoline. Alkaloid L.8 (C16H25O2N) has only been studied by infrared spectroscopy where it shows carbonyl and hydroxyl absorption. All four alkaloids therefore contain a basic tetracyclic ring system as do the majority of other lycopodium alkaloids. Annotoxine, a molecular compound of acrifoline and annotine, has been isolated from extracts of Canadian plant material.
Annotine, C16H21O3N, is shown to be pentacyclic and to contain a tertiary hydroxyl group, a lactone function, a tertiary nitrogen atom, and a dialkylated double bond. The position of the double bond and the tertiary hydroxyl group relative to the nitrogen atom has been established by Emde degradation of annotine methiodide. The presence of a lactone function is inferred from the reduction of annotine to dihydroannotinol, a hemiacetal, which reacts with 1 mole of ethyl mercaptan. The reduction of the lactone to a diol in an annotine derivative has been carried out. The chemical studies and the examination of annotine and its derivatives by modern instrumental methods allow the assignment of a plausible structure to the alkaloid.