STETTf'TITRE OF T?IE K VITAMINS 



887 



The nature of the side chain attached to the naphthoquinone nucleus 

 can readily be determined. McKee et al.^*^ found that 9 molecules of hy- 

 drogen were absorbed on catalytic hydrogenation. Since only 3 molecules 

 arc involved in the reduction of the naphthoquinone to the naphthohydro- 

 quinone structure, there must be 6 double bonds in the side chain. This is 

 further confirmed by the proof that dihydrovitamin K2 diacetate, which 

 cannot add bromine to the naphthohydroquinone ring, adds 6 molecules of 

 bromine. Moreover, it was shown that the double bonds are not in con- 

 jugation, since no addition product obtains on treatment with maleic an- 

 hydride; further support for the absence of conjugated double bonds 

 (other than in the quinone ring) can be adduced from the ultraviolet absorp- 

 tion curve. 





 II 



u O-CCH, 



HC C CCHj ^^ ^^ ^^ P^ p^ ^^ 



I il I «J >J ^ I N I < I ^. I 



HC. C ,CCH2CH:t.CCH2CHj,CH:ECCH2CH2CH^C GHjCHjCH^CCHjCHjCHifGGHjGHjCHiFCGHj 

 C C^ \ ^ V > > 



H I ^-rr 



0-GGH, . . Al 



II 











II 



H 9-CCH3 



HG' G GCH, 



.•^ 



O 



CH, .0 



5 0=C-GH,-GH,-C-H 







II 

 CH.-C-GH, 



HG. G XCHjG-H 



G^ G 



H I 



0-CGH, 



xni 



XEZ 







xn 



Oxidation of Dihydrovitamin K2 Diacetate 



The nature of the side chain is at once evident when the products of 

 ozonolysis are known. ^^-^^ These consist of l,4-diacetoxy-2-methylnaph- 

 thalene-3-acetaldehyde (XII), levulinaldehyde (XIII), and acetone (XIV). 

 The l,4-diacetoxy-2-methylnaphthalene-3-acetaldehyde was characterized 

 by forming the semicarbazone, as was the case when this product was 

 identified as a decomposition product of vitamin Ki. Levulinaldehyde 

 was obtained in 93% yield calculated on the basis of 5 moles per molecule of 

 vitamin K2; it was identified as the bis-2,4-dinitrophenylhydrazone, pre- 

 pared earlier bj^ Strain. ^^ Acetone was also detected as its 2,4-dinitro- 



5^ H. H. Strain, J. Biol. Chew., 102, 1.51-155 (1933). 



