KARL FOLKERS 



tocopheryl allophanate. The chromic acid oxidation of this acetate 

 yielded diacetyl, acetone, an acid C16H32O2 of probable structure VI, 

 and a ketone CigHseO. 



CHg CHj CIH3 



i I i 



HOOCCH2CH2CH(GH2)3CH(CH2)3GHCH3 



(VI) 



The interpretation of these degradation products and related 

 evidence led to the proposal by Fernholz (9) of structure VII for a- 



CH3 Cri2 

 HOr/N^ ^CHs CH3 CH3 CH, 



CHs^X Js.^ y-C(Cri2)3CH(Cri2)3Cri(Cri2)3CriCH3 



CH3O I.H3 



(VII) 



tocopherol. Although the related coumaran structure was con- 

 sidered further by Karrer, Fritzsche, Ringier, and Salomon (22,23) 

 all the results of the investigations — refer to review paper by Smith 

 (44) — were soon interpreted in favor of the chroman structure VII, 

 which was proposed after a study of a few relatively large-scale deg- 

 radation reactions. 



An interesting aspect of the structure studies on thiamin and 

 biotin was the application of new organic structural reactions. It 

 had been observed during the isolation work that an attempt to use 

 sulfurous acid as a preservative against the bacterial decay of extracts 

 of vitamin Bi from rice polish caused a prompt and complete loss of 

 vitamin activity. This observation led to the development of a pro- 

 cedure by Williams, Waterman, Keresztesy, and Buchman (71) for 

 the quantitative cleavage by sulfite of pure crystalline vitamin Bi at 

 pa 5 and room temperature into two products of the composition 

 C6H9N3SO3 and CeHgNSO. There are obvious advantages of this 

 reaction over the usual oxidative and hydrolytic reactions which ap- 

 peared to give a miscellany of substances. The reaction is expressed 

 in terms of the structural formulas by the following equation: 



CH3 



N=CNH3+C1- C CCH2CH2OH 



CH,C C— CH2— N'+ 



N— CH CI- CH- 



+ Na2S03 



96 



