CHEMICAL CONSTITUTION 



R. Kuhn and G. Wendt ^ showed that, on treatment with diazo- 

 methane, vitamin Bg (which they called adermin) yielded a methyl 

 ether which was converted into a diacetyl ether on acetylation. They 

 therefore concluded that all three oxygen atoms in adermin were 

 present in the form of hydroxyl groups, one phenolic and the other 

 two alcoholic and that, since diacetyl adermin methyl ether contained 

 no active hydrogen atom, the nitrogen atom was tertiary. 



The position of the phenolic hydroxyl group was established ^ by 

 the fact that vitamin Bg, like ^-hydroxypyridine, gave a positive 

 reaction with the Folin-Denis phenol reagent, ^ whereas a and y-hy- 

 droxyp^Tidine did not. Confirmation was obtained by the close 

 resemblance between the absorption spectra of vitamin Bg and j8-hy- 

 droxypyridine. That the two alcoholic hydroxyl groups were not on 

 adjacent carbon atoms was shown ^ by recovery of unchanged adermin 

 methyl ether after treatment with lead tetraacetate. 



Oxidation of the methyl ether with neutral potassium perman- 

 ganate solution resulted in the formation of a lactone, C9H9O3N, by 

 removal of four hydrogen atoms, suggesting that the aliphatic hydroxyl 

 groups were in the i : 4 or i : 5 positions. Oxidation with alkaline 

 potassium permanganate solution yielded the anhydride of a di- 

 carboxylic acid, C8H5O4N, with loss of a molecule of carbon dioxide. 

 Oxidation by barium permanganate * gave the dicarboxylic acid. By 

 more cautious treatment with potassium permanganate, loss of carbon 

 dioxide was avoided and a tricarboxylic acid, C9H7O7N, was obtained. 

 From an examination of its absorption spectrum, it was concluded 

 that the anhydride was either 



CO 



OC— i 



OCH, 



,CO 



/ \ II 



OCH, 



^N 



CO^ 



(I) 



(11) 



and the tricarboxylic acid therefore 



COOH COOH 



HOOC, 



OCH, 



HOOC 



or 



HOOCL ]) 



N' 

 (HI) 



I II 

 1 II 



(IV) 



OCH3 

 COOH 



HOOC 

 HOOC^ 



OCH3 

 COOH 



(V) 



As the tricarboxylic acid gave a blood-red colour with ferrous sulphate, 

 characteristic of pyridine- a-carboxylic acid, whereas the dicarboxylic 

 acid gave no such colour, formula II for the anhydride, and formula 



299 



