Spectra of Lycopodium Alkaloids

In 1963 MacLean examined the spectra of annotinine, lycodine, a- and yS-obscurine, selagine, lycopodine, and a number of alkaloids with the lycopodine skeleton (107). His studies showed that mass spectrometry could be used advantageously in structural problems on this family of 

The presence of substituents on the bridge in the lycopodine skeleton is easily determined by mass spectrometry. Thus clavolonine and faw-oettiine which have C-8 hydroxyl groups show intense peaks at M-73 in their spectra while annofoline which has a ketone group at C-8 shows an intense peak at M-71. Substituents at other sites on the lycopodine skeleton give rise to the appearance of peaks characteristic of the substituent and its position however, the loss of the bridge carbon atoms is nearly always a dominant feature of the spectrum. 

In the spectra of lycodine and alkaloids related to it the loss of the bridge carbon atoms is again a major fragmentation route. In lyconnotine the loss of the side ehain at C-13 is observed and in annotine the bridge and the associated lactone function are eliminated. In annotinine intense peaks are found at M-42 and M-86 associated with the sequential loss of the bridge and of carbon dioxide. Thorough studies of the spectra of cernuine and of serratinine have not yet been reported. 

Jenkins, and S. Valverde-Lopez, Tetrahedron Letters 2201 (1964). Y. Inuhushi, H. Ishii, B. Yasui, M. Hashimoto, and T. Harayama, Tetrahedron Le ers 1537 (1966). 

Inuhushi, Y. Tsuda, H. Ishii, T. Sano, M. Hosokawa, and T. Harayama, Yakugaku Za.sshi 84, 1108 (1964). 

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Lycoflexine (1), isolated from Lycopodium clavatum var. inflexum, is a representative of a new skeleton hitherto not encountered in this group of alkaloids. Lycoflexine showed in its mass spectrum a base peak at mje 84 which had not been previously encountered in mass spectra of Lycopodium alkaloids. The structure was solved by X-my crystallographic analysis of its hydrobromide derivative. Lycoflexine may be biogenetically related to the known fawcettimine (2), which also occurs in L. clavatum var. inflexum, by invoking an intramolecular Mannich reaction on an initially formed immonium salt (3). 

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