Raper

In 1931 Winterfeld and Kneuer, as a result of their observation that jS-lupinane can be obtained from lupanine, and the formation of 2-methyl-pyrrolidine by the oxidation of sparteine, combined these two features in a partial formula (II) for lupanine, which could be developed in various ways depending on the mode of attachment of the methylpyrrolidine residue. In view, however, of Ing s demonstration of the relationship of anagyrine, CJ5H20ON2, to Z-lupanine, CJ5H24ON2, and d-sparteine, C15H28N2, it was elearly neeessary to consider formul for lupanine derivable from the two alternati-ves, which Ing had proposed for anagyrine and which are shown below as (III) and (IV) with the formul for lupanine derived from them (V) by Ing and (VI) by Clemo and Raper. Sparteine would be represented by (V) or (VI) with the change CO CH2. 

Formula (VI) has received support in two ways. The investigations of Winterfeld (with Ronsberg) on the oxidation of dehydrosparteine methoaeetate and of a-didehydrosparteine, indicated thatD was a piperidine ring and this was finally established by Clemo, Morgan and Raper a... 

Me. (CHj). CHMe. CHj. CHMe. (CH2)4Me and Schirm and Besendorf have synthesised the latter and identified it with the sparteine hydrocarbon. Clemo and Raper have modified Ing s formula to (VIII). The latter provides an explanation of the fact that sparteine yields two monomethiodides, which appear to be stereoiso-merides, but does not yield a dimethiodide. Examination of a space niodel of (VIII) shows that if the two octahydropyridocoline systems are both trans and if the C, — C, bridge is cis with respect to the hydrogen atoms attached to C and C the system is fairly rigid and the nitrogen atoms are so close to each other that the formation of a dimethiodide is Impossible. Couch has proposed a new numbering system for the Sparteine formula as shown in (Villa). 

Support for (VIII) has been provided by Clemo, Morgan and Raper s... 

The interesting relationships between the five most important alkaloids in this group, which have been made clear by these investigations, are shown by formulae (I) to (VI) on p. 141. The synthesis of oxysparteine by Clemo, Morgan and Raper (p. 138) supports formula (II) for anagyrine. 

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