320 Essays in Biochemistry- 



It was shown by these investigators that rockogenin (12/3-hydroxy- 

 tigogenin, XXXVI), when treated in the form of its 3-methylsuccinate- 

 12-mesylate with potassium £-butoxide in £-butanol, or with the alcohol 

 alone, was transformed in fairly facile reaction into a mixture of the 

 C-nor/D-homospirostene XXXVII and its 17,17a double-bond isomer. 

 Similarly, the 12-toluene-p-sulfonylhydrazone derivative of 11-keto- 

 hecogenin (XXXVIII) with alkali yielded the rearrangement product 

 XXXIX, reminiscent of jervine. Since an ll/?-hydroxy-12-keto bile 

 acid also undergoes this rearrangement, it is clear that the constitu- 

 tional requirements are rather simple: a 12-keto or 12/J-hydroxyl group 

 in an activated state such as supplied here by the tosyl group in the 

 derivatives used. The authors suggest that the veratrum alkaloids 

 possessing the modified nucleus may arise in the plant by rearrange- 

 ments of this kind from similarly constituted precursors. Against this 

 hypothesis can be held the fact that there is no evidence for the 

 occurrence in the plant sources of rockogenin and hecogenin of products 

 of the type obtained by Hirschmann et al. The question could be 

 presumably settled by growing veratrum plants in the presence of 

 1-C 14 - and 2-C 14 -labeled acetate and determining the isotope distribu- 

 tion in suitable degradation products of the more abundant "abnormal" 

 alkaloids, but, aside from the great practical difficulties inherent in a 

 project of this kind, it would obviously have to await the demonstra- 

 tion of a constant distribution pattern of acetate carbons in several 

 classes of plant steroids including normally constituted steroid alka- 

 loids, since so far it is only a presumption that the pattern ascertained 

 for the cholesterol nucleus holds true for all steroids. 



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