II. CHEMISTRY 



393 



At very low pressures, 10~* to 10~^ mm. of mercury, vitamin Ki could 

 be distilled at 120 to 140° with little or no loss.'^' -^ Vitamin K2 was distilled 

 with some loss at 2 X lO"" mm. and 200°. 



C. CONSTITUTION 



The characteristic yellow color of these purified vitamins, the loss of 

 color upon hydrogenation, and its reappearance upon exposure to oxygen 

 in air suggested that the vitamins might be quinones.^^ • '* Among a num- 

 ber of bacteria tested Mycobacterium tuberculosis had been found to possess 



CH3 

 CH2CH-C(CH2)3CH(CH2)3CH(CH03CHCH3 



CH3 CH3 



Vitamin Ki 



I 

 CH3 



CH3 



iCHj 



2-Methyl-l ,4-rlaphthoquinone- 

 3-acetic acid 



OCOOH 

 COOH 



Phthalic acid 



0=C(CH2),CH(CH2)3CH(CH2),CHCH3 

 I II I 



CH3 CH3 CHj CH3 



2,6, 1 0-Trimethylpentadecanone- 1 4 

 Fig. 2. Oxidation products of vitamin Ki . 



appreciable vitamin K activity .^^ The principal pigment in the lipids of 

 this organism had been isolated and synthesized by Anderson and coworkers 

 several years before.^^ The pigment, phthiocol, was 2-methyl-3-hydroxy- 

 1 ,4-naphthoquinone (Fig. 2). Certain features of the absorption curve and 

 other properties of this compound compared closely with those reported 

 for vitamin Ki. Synthetic phthiocol tested with vitamin K-deficient chicks 

 was found to be distinctly active in restoring normal blood-clotting time 

 and thus became the first completely identified form of vitamin K.^'* The 

 next step was to test the functional importance of the methyl and hydroxyl 



'2 H. J. Almquist, C. F. Pentler, and E. Mecchi, Proc. Soc. Exptl. Biol. Med. 38, 336 



(1938). 

 " R. J. Anderson and M. S. Newman, ./. Biol. Chem. 101, 773 (1933). 

 " H. J. Almquist and A. A. Klose, /. Am. Chem. Soc. 61, 1611 (1939). 



