58 



VITAMINS A AND CAROTENES 



vitamin A was oxidized with vinadium tetroxide (¥204).^''^"-^'' Apparently 

 retinenei is first formed, which is subsequently hydroxylated to give anti- 

 vitamin A. The ultraviolet spectrum of this product shows two maxima 

 at 290 and 340 m/x, respectively, and its antimony trichloride color shows 

 a maximum at 545 m/x. Meunier-^" has proposed two structures (CVI and 

 CVII) for this product. 



HsC 



CH3 



-CH3 



CH 



CH3 OH CH3 



OH 



OH 



HC3 CH3 



-CH3 



CVI 



it 



OH 



CH3 OH 



CH3 



CH=0 



CVII 



Finally, mention should be made here of an unknown substance with 

 vitamin A activity obtained from lard by high-vacuum distillation.-^i- 212 

 Apparently the identity of this substance is still unknown. 



200 N. A. Milas, S. W. Lee, C. Schuerch, Jr., R. O. Edgerton, J. T. Plati, F. X. Grossi' 



Z. Weiss, and M. A. Campbell, J. Am. Chem. Soc. 70, 1591 (1948). 

 2"! N. A. Milas and M. T. Burgess, Paper presented before the 2nd Intern. Congr. 



Biochem., Paris. July, 1952. 

 202 G. W. H. Cheeseman, I. Heilbron, E. R. H. Jones, and B. C. L. Weedon, J. Chem. 



Soc. 1949, 3120. 

 2»3 B. C. L. Weedon and R. J. Woods, J. Chem. Soc. 1951, 2687. 

 204 I. Heilbron, E. R. H. Jones, D. G. Lewis, and B. C. L. Weedon, J. Chem. Soc. 



1949, 2023. 

 206 J. B. Toogood and B. C. L. Weedon, J. Chem. Soc. 1949, 3123. 



206 I. Heilbron, E. R. H. Jones, and R. W. Richardson, /. Chem. Soc. 1949, 287. 



207 L Heilbron, E. R. H. Jones, D. G. Lewis, R. W. Richardson, and B. C. L. Weedon, 

 J. Chem. Soc. 1949, 742. 



208 P. Meunier, J. Jouanneteau, and R. Ferrando, Compt. rend. 230, 140 (1950). 



209 p Meunier, G. Zwingelstein, J. Jouannotoau, and R. Mallein, Compt. rend. 230, 

 1323 (1950). 



210 p. Meunier, Fortschr. Chem. org. Natursloffe 9, 102 (1952). 



211 H. Kaunitz and C. A. Slanetz, J. Nutrition 42, 375 (1950). 



2»2 H. Kaunitz and C. A. Slanetz, Proc. Soc. Exptl. Biol. Med. 76, 322 (1950). 



