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Simple, stereospecific syntheses of 14C-labelled (f) -trans-chrysanthemum mono-and di-carboxylic acids, required for biosynthetic and toxicological work, are described. The methyl esters of the acids are obtained by Wittig condensation between the (+) -trans-cyclopropane aldehyde (2) and the appropriate 14C-labelled phosphoranes. Aldehyde (2) is obtained in high yield by osmium tetroxide-sodium periodate oxidation of methyl trans-chrysanthemate. The conversion of methyl chrysanthemate into chrysanthemum dicarboxylic acid via aldehyde (2) proceeds in an overall yield of 39%.Methyl nor-( 9) and bisnor-(8) (*) -trans-chrysanthemates are synthesised from (2) by condensation with a p p ro p r i at e a I ky I i den e p hos p h o ra n es.

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Amides of Vegetable Origin. Part IV.* The Nature of Pellitorine and Anacyclin. (I) Pr**CH=CH*CH,-CH,CH=CH*CO.NH Bu' MefCHJ ,.CH%H-CHzCH *CO.NH Bu' (I I) * Part 111, preceding paper. * ! M.p. no.' (mp) m p (max.

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The absolute configuration of natural rotenone is determined at centres 6a and 6' by exhaustive ozonolysis and oxidation. The 5'-centre was extracted from the rotenone degradation product ( -)-dihydrotubaic acid as ( +)-3-hydroxy-4-methylpentanoic acid. Synthesis and resolution gave the (-)-form of the latter, and this was degraded to (-)-2-methylpentan-3-01, which can be related to L-glyceraldehyde by correlations in the literature. The 5'-centre of rotenone has the (R)-configuration. Ozonolysis of the enol acetate of dihydrorotenone, which has the same configuration as rotenone a t positions 6a and 5', gave (-)-D-glyceric acid containing the 6a-centre, whose configuration is therefore (S) .Conformation in the rotenone molecule, which has the stable form of B/C fusion, is considered. Closely related 12a-hydroxy-derivatives are shown to be more stable with a cis-than with a transfusion. Reduction of rotenone and compounds known to have the same B/C fusion as rotenone, [( -J-)-isorotenone, (-)and (A)-dihydrodeguelin] gives crystalline 12hydroxy-compounds which show intramolecular hydrogen bonding. This is adequately explained only when O(,> is the acceptor, a situation possible only with a cis-fusion. Other evidence supports the assignment and it is in agreement with study of the hydrogenation of rotenoid derivatives. It follows that the configuration of rotenone a t 12a is (S), and the complete configuration is (6aS, 12aS, 5'R), as shown in formula (I).STRUCTURAL investigations of the insecticidal compound rotenone, which occurs in members of the Leguminosz, culminated in the proposal (I without stereochemical designation) .l The stereochemical problem could be solved by three determinations of absolute configuration two determinations of absolute and one of relative configuration, or one determination of absolute and two of relative configuration. We have chosen the second course. First, the absolute configuration is determined at 5', and then again at 6a since it would be difficult to relate these centres to each other. Finally, the mode of 1 (a) LaForge and Haller,