VITAMIN RESEARCH 



c:h, 



N-=CNH2 c-^,,^cCH2CH.OFI 



/ \ / 



CH3C CCH2SO3H + N 



N— CH CH — 



+ 2 NaCl 



The new organic structural reaction used in the investigation 

 of biotin was applied in the belief that the results would lead to a final 

 selection between two alternative structures for biotin. It was believed 

 that organic sulfides could be cleaved by the Raney nickel catalyst 

 according to the equation: 



Ni(H) 

 RSR' ^ J. RH + R'H 



This sulfur hydrogenolysis reaction was developed first on several 

 "model" compounds. It was found by Mozingo, VVolf, Harris, and 

 Folkers (35) that representative sulfides could be cleaved to their 

 corresponding sulfur-free products in yields of 65 to 95% on both a 

 macro and semimicro scale. As described by du Vigneaud, Melville, 

 Folkers, Wolf, Mozingo, Keresztesy, and Harris (60), the application 

 of this hydrogenolysis reaction to biotin methyl ester yielded dcsthio- 

 biotin methyl ester, and the subsequent study of this hydrogenolysis 

 product was the first of two independent methods which led to the 

 final proof of the structvu-e of biotin. It was considered originally 

 (35) that this reaction would be of general value in investigations on 

 the structures of natural products containing sulfur. 



On the Use of Microorganisms in Vitamin Researcli 



It is beyond the scope of this article to present all of the interest- 

 ing aspects of the application of microorganisms to vitamin research. 

 Williams recently discussed the importance of microorganisms in \-ita- 

 min research (62) and reviewed microbiological tests (64). Gyorg\' 

 reviewed further developments in the use of microorganisms in vitamin 

 research (12). There are, however, certain recent developments in 

 the chemistry of vitamin Bg which were originally provoked l)\- the 

 results of microbiological experiments, and recent results on new vita- 

 mins which seem to merit comment. 



Snell, Guirard, and Williams (50) found that assays with 

 Streptococcus lactis gave values for the pyridoxine content of certain 



97 



