The Veratrum Alkamines 317 



in its support. A very brief and cursory exposition of the main lines 

 of evidence will have to suffice. One of these developed out of a 

 reconsideration of the properties and mode of formation of decevinic 

 acid, C14H14O6, a degradation product already extensively explored by 

 Jacobs and Craig and now shown to be XXVI. Decevinic acid is 

 formed by pyrolytic dehydration of one of the chromic acid oxidation 

 products of cevine, a lactone tricarboxylic acid of the composition 

 Ci 4 Hi S O s . The recognition of this lactone as XXVII, partly implicit 

 in XXVI, and of another closely related oxidation product, a hexane- 

 tetracarboxylic acid Ci Hi 4 O 8 , as XXVIII showed these fragments to 

 be derived from a normal A/B ring system substituted with oxygen at 

 C-3, C-4, and C-9, and beyond that provided confirmatory evidence 

 (preservation in XXVII of carbon atom 13 * in the oxidative scission) 

 for ring C being five-membered ( Jeger, Prelog, Woodward) . 



At this point it was possible to accommodate in the positions men- 

 tioned a masked secondary a-ketol system which had been disclosed 

 by the work of Barton, and further to place tentatively an independent 

 ditertiary glycol grouping (Stoll and Seebeck, Barton) at the C/D 

 bridge atoms 13 and 14. More decisive evidence on this latter point, 

 as well as on the location of one other hydroxyl group, derives from 

 the properties and reactions of the "anhydrocevine" formed from cevine 

 on vigorous acetylation followed by hydrolysis (Stoll and Seebeck). 

 This compound is now shown to be a tritertiary orthoacetate (Barton) 

 which must be formulated as XXIX, since other possible sites for the 

 hydroxyl groups linked together in the orthoacetate grouping may be 

 excluded on the strength of periodate titration data, as well as for 

 other reasons (for instance, XXX below) . The presence of a secondary 

 hydroxyl group at C-16 is deduced, inter alia, from the structure 

 (XXX) assigned to a product which is formed from the ester alkaloid 

 cevadine (XXXIIa) on chromic acid oxidation. This compound is 

 undoubtedly a phenolic indanone and is thought to arise from the 

 intermediary seco-13,14-diketone XXXI by transannular Claisen con- 

 densation (C-13^C-15), followed by dehydration at C-9, and aro- 

 matization of ring C (Jeger, Prelog) . The allocation of the remaining 

 hydroxyl group, which must be tertiary, to C-20 rests in essence on 

 the (as yet unproved) structure of the dehydrogenation product IV. 



It is now well established that an isomer of cevine, veracevine, and 

 not cevine itself is the true native alkamine occurring in the ester 



* Numbering according to proposals for steroid nomenclature now before Union 

 internationale de chimie pure et appliquee (cf. ref. 12). Barton et al. 1 designate 

 the carbon atoms here numbered 13 and 17a as 12 and 13, respectively. 



