Aspidospermine methiodide

The X-ray analysis of (—)-aspidospermine methiodide established the absolute configuration 253 for this compound (279). 

The structure of aspidospermine (II) was practically solved by chemical degradative methods (see formula CCCCXXXIII, Volume VII, p. 131) but the final location of the ethyl side chain and the relative stereochemistry only became known after the single crystal X-ray study of its methiodide (22, 11) which was shown to have structure X.1 Extensive degradative work, the results of which appeared side by side with those of the X-ray determination, had shown the nature of the structure around both nitrogen atoms and established the size of rings D and E (24, 12). 

Although the structure of (— )-aspidospermine-Ab-methiodide (V) was determined by X-ray crystallography (Volume VIII, p. 361) its... 

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