ANALOGUES 



3-Benzyl-5-^-hydroxyethyl-4-methyl-thiazoliiim chloride was like- 

 wise inactive. As might be expected, however, both compounds 

 stimulated the growth of Phycomyces when the pyrimidine half of the 

 aneurine molecule was present in the culture fluid. 



Erlenmeyer et al.'^^'* prepared two other analogues of aneurine, in 

 which the thiazole ring is replaced by an iminazole ring. They were 

 obtained by coupling the pyrimidine half of the aneurine molecule 

 with 5-hydroxymethyl- and 5-j8-hydroxyethyl-4-methyl-iminazole. 



Simple Derivatives of Aneurine 



Of the simple derivatives of aneurine, all the halogen salts are active. 

 It has been claimed ^^ that aneurine iodide hydriodide, m.p. 230 to 

 231° C, is actually more potent than aneurine chloride hydrochloride, 

 but no suggestion has been put forward as to the reason for this. 



The preparation of several water-insoluble salts of aneurine for use 

 in the enrichment of cereals was described by Huber et al.^^ Water- 

 soluble salts such as the chloride, when used for this purpose, are 

 washed off in the rinsing preparatory to cooking, with consequent loss 

 of the vitamin. The 2-ethylhexyl sulphate, the methylene-bis-(2- 

 hydroxy-3-naphthoate) and cholestenone-6-sulphonate of aneurine 

 were prepared and found to be sparingly soluble in water, the last 

 two being practically insoluble. All three were biologically active. 

 Salts of other alkyl sulphuric acids could only be obtained as oils, as 

 also could the salts of isopropyl-naphthalene-sulphonic acid and di- 

 octylsulphosuccinic acid. The aneurine salt of dibutylsulphosuccinic 

 acid was foimd to be water soluble. 



The only other simple derivatives of aneurine to be prepared are 

 the esters . F. Schultz,* found that the pyrophosphate (cocarboxylase) , 

 the monophosphate, acetate, benzoate, and chaulmoograte had a 

 more prolonged action than aneurine, whilst the phenylurethane, 

 though active, did not produce 100 % cures in vitamin Bi-deficient 

 rats. The preparation of the orthophosphoric and pyro phosphoric 

 esters of aneurine was described by J. Weijlard.^^ The latter was 

 prepared not only by direct esterification of aneurine, but also by 

 condensation of 4-amino-5-bromomethyl-2-methyl-pyrimidine hydro- 

 bromide with 5-jS-hydroxyethyl-4-methyl-thiazole pyrophosphate on 

 the one hand and with 5-j3-chloroethyl-4-methyl-thiazole in presence 

 of silver pyrophosphate on the other. Weijlard also prepared aneurine 

 sulphate but did not record its activity. 5-/3-Hydroxyethyl-4-methyl- 

 thiazole pyrophosphate could not replace cocarboxylase in the enzy- 

 matic decarboxylation of pyruvic acid.^^ Qn the contrary, it in- 

 hibited cocarboxylase activity, presumably by competition with 

 aneurine pyrophosphate for the specific enzyme, carboxylase. 



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