Akuammigine type alkaloids

The spectra of the i/i-akuammigine-type alkaloids (270) show peaks which indicate merely the easy loss of one molecule of formaldehyde, followed by the expulsion of a carbomethoxy group, thus hindering the detection of special structure features.159, 160 However, the fragmentation pattern becomes richer in characteristic fragments if... 

Further elaboration of tetracycle 159c resulted in the syntheses of the racemate of indole alkaloids of the ajmalicine (61JA2594), tetrahydroalstunine (56JOC1315, 71JA5907), and akuammigine type (ajmalicinoid alkaloids). Similarly, 159d can be converted into yohimboid alkaloids (79JA5370). 

The interval since the last review was written has seen the isolation of a number of new alkaloids but of few fundamentally new skeletal types. Meloscine (I) (1) and related alkaloids represent a completely novel group, whereas aspidodasycarpine (II) (2) is a new variation of the akuammigine type. 

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