838 X. THE VITAMIN K GROUP 



phenylhydrazone, and by iodometric titration. Assuming that one mole- 

 cule of acetone originates on the oxidation of one molecule of vitamin K2, 

 the recovery amounted to only 53% of the theoretical value. ^^ The origin 

 of the fragments is pictured on page 837. 



These data on degradation products are consistent with the formula as- 

 signed to vitamin K2, which pictures it as 2-methyl-3-difarnesyl-l,4-naph- 

 thoquinone. 



(5) Constitution of Menadione 



Although 2-methyl-l,4-naphthoquinone, or menadione, does not occur 

 naturally, it is the most powerful of all antihemorrhagic agents. The struc- 



H ^ 



/^\ /\ 



HC C CCH, 



I If II 



H II 







SZ 



ture of this compound (XV), which is shown here, can readily be ascer- 

 tained by S3aithesis.^^'^^ 



4. Synthesis of the K Vitamins 



(1) Synthesis of Vitamin Ki 



Vitamin Ki was synthesized by Almquist and Klose^* by the simple 

 expedient of condensing 2-methyl-l,4-naphthoquinone with the alcohol 

 phytol (XVII). The dihydrovitamin Ki (XVIII) so produced was readily 

 oxidized to vitamin Ki. Somewhat better results appear to occur when 2- 

 methyl-l,4-naphthohydroquinone (XVI) is used instead of the naph- 

 thoquinone for condensation with phytol in the presence of such cat- 

 alysts as oxalic acid or trichloracetic acid in dioxane.^" The Doisy group ^^-^ 

 condensed the monosodium salt of 2-methyl-l,4-naphthohydroquinone with 

 phytyl bromide to produce vitamin Ki. 



H OH 



HC' C ■'CCH3 ^^i CHj CH3 CHj 

 I i| I -4- HGCHjCH^CCHaCHsCHjCHCHjCHjCH^CHCHjCHjCHjCHCHj *- 



H OH 



X2E 



« p. p. T. Sah, W. Brilll, and H. Holzen, Ber., 73, 762 (1940). 

 6« P. P. T. Sah, Rec. trav. chim., 59, 461-470 (1940). 



6^ D. W. MacCorquodale, L. V. C'henev, S. B. Binkley, W. F. Holcomh, R. W, McKee, 

 S. A. Thayer, and E. A. Doisy, /. RioL'Chem., 131, 357-370 (1939), 



