(VI) (VII) 



Kuhn et al.^ synthesised the anhydride represented by formula I 

 and found it to be identical with that from adermin, thus confirming 

 that the latter must have structure VI or VII. They * also synthesised 

 3-methoxy-2-methyl-pyridine-4 : 5-dicarboxylic acid and showed that 

 it was identical with the dicarboxylic acid obtained by treating ader- 

 min methyl ether with barium permanganate. 



Stiller et al.^ also obtained the lactone, C9H9O3N, by treating the 

 methyl ether of adermin with barium permanganate, together with a 

 dibasic acid, C9H9O5N, which they presumed to be 3-methoxy- 

 2-methyl-pyridine-4 : 5-dicarboxylic acid, since it yielded a phthalein 

 on fusion with resorcinol and a hydroxypicoline on being heated with 

 calcium hydroxide. Its constitution was confirmed by synthesis, 

 accomplished by S. A. Harris, E. T. Stiller and K. Folkers.^ 



Pyridoxal and Pyridoxamine 



As a result of a study of the effect of pyridoxine on micro-organisms 

 (see page 212), Snell et al.^ discovered the existence in various natural 

 materials of two substances closely related to pyridoxine. These were 

 identified as 4-formyl-3-hydroxy-5-hydroxymethyl-2-methyl-pyridine, 

 to which the name pyridoxal was given, and 4-aminomethyl-3-hydroxy- 

 5-hydroxymethyl-2-methyl-pyridine, which is known as pyridoxamine. 

 CHO CH2NH2 



Ho/Vh^OH Ho/^jCHaOH 



chJ- II 



CH. 



>n/ 



The former was produced from pyridoxine by oxidation with potassium 

 permanganate, manganese dioxide, potassium dichromate or potassium 

 ferricyanide, and the latter by treatment with ammonia.^ Pyridoxal 

 was converted into pyridoxamine by heating with casein hydrolysate 

 or glutamic acid, whilst the reverse change was effected by heating 

 pyridoxamine with a-ketoglutaric acid.^^ Other amino acids effected 

 the transformation of pyridoxal into pyridoxamine, but not so readily 

 as did glutamic acid. 



The structure of these two substances was established by Harris 

 et al}^ who synthesised the isomer of pyridoxamine, 5-aminomethyl-3- 



300 



