ANEURINE (thiamine) 



Pyrithiamine actually antagonises the growth of some micro- 

 organisms (see page 126). 



Unfortimately, p3^ithiamine seems to have met a similar fate to 

 Baumgarten and Dornow's pyridine analogue, for A. N. Wilson and 

 S. A. Harris ^^^ claim that it does not possess the above structure, 

 assigned to it by Tracy and Elderfield. They in their turn claim to 

 have prepared an authentic specimen of this elusive substance, and 

 report that it has an absorption spectrum similar to that of aneurine. ■ 

 They have named the new substance neopyrithiamine, and suggest 

 that pyrithiamine is a mixture of compounds having pyridine and 

 pyrimidine moieties in the ratios 1:2, 1:3, 1:4, etc. Neopyri- 

 thiamine is a more potent antagonist of aneurine than is pyrithiamine 

 (see page 127). 



W. H. Schopfer^^ tested the two compounds prepared by 

 Baumgarten and Dornow, and found that, although they had only 

 slight vitamin B^ activity, they stimulated the growth of Phycomyces 

 Blakesleeanus and Ustilago violacea in presence of the thiazole half of 

 the aneurine molecule. These organisms therefore appear able to 

 cleave the pyridinium derivatives and utilise the resulting pyrimidine 

 portion for the synthesis of aneurine. Compounds with weak growth- 

 promoting activity were obtained by coupling the pyrimidine half of 

 the aneurine molecule with 3-acetyl pyridine.^®^ 



A pyrimidine analogue of aneurine, 3-(4'-amino-2'-methyl-5'- 

 pyrimidyl-methyl) - 6 - hydroxy-5-j3-hydroxyethyl-4-m ethyl - pyrimidin- 

 ium bromide hydrobromide : 



N=C . NHa CH3 . C=C . CH2 . CH2OH 



CH3.C C CH2 N C.OH 



11 II /W 11 



N-CH Br^H-N ^^^ 



was prepared by Y. A. Tota and R. C. Elderfield,^' and tested by 

 W. J. Robbins ^^ on Phycomyces Blakesleeanus, Pythiomorpha gonapo- 

 dioides and Phytophthora cinnamomi. It had little or no effect on any 

 of these moulds. 



Another heterocyclic analogue of aneurine was tested by W. H. 

 Schopfer ^^ on Phycomyces Blakesleeanus and foimd to have no appreci- 

 able biological activity. This was the compound, 3-[4'-(5'-methyl- 

 imidazolyl)]-5-j3-hydroxyethyl-4-methyl-thiazolium chloride in which 

 the pyrimidine ring was replaced by an imidazole ring : 

 CH3 CH3 



N C. . C C . CH2 . CH2OH 



II >-< I 



N— CH^ / x:h— s 



CI 



124 



