Major fragments produced from aspidospermine upon electron impact

Major fragments produced from aspidospermine upon electron impact 

Kopsine. Kopsine is a heptacyclic alkaloid which at first sight would appear to offer little hope of rapid structure elucidation, but the reader should remember how much information can be gotten out of quite simple measurements. The nature of its chromophoric moiety followed from its ultraviolet absorption spectrum the infrared revealed its carbonyl functionalities. From the above, the elemental composition, Zeisel and Kuhn-Roth determinations and behaviour towards hydrogenation it seemed to be a heptacyclic-N-methoxycarbonylindoline containing a keto-carbonyl and a hydroxyl group. 

The reader should also be aware that such a highly condensed rigid system lends itself (and its derivatives) to analysis by nuclear magnetic resonance spectroscopy. In this way much of the proton topography becomes known and the problem is to fit it onto a unique carbon-nitrogen matrix. One of the really important 

Kopsine methiodide upon treatment with sodium carbonate at room temperature gave a methine base (reverse of a Michael addition) and the methylene protons of the resulting vinylketone were not split by any other adjacent protons. 

Kopsinyl iodide derived from pleiocarpine upon pyrolysis gave besides kopsinylene and other products, kopsan in 6 % yield. This reaction is thought to proceed via radical intermediates. Kopsan was identical in all respects with the product obtained in very small 

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