I. NOMENCLATURE AND FORMULAS 6 



3. Requirements for Vitamin A 172 



4. Features Influencing Requirements 174 



I. Nomenclature and Formulas 



ROBERT S. HARRIS 



Accepted names: Vitamin A 



Neo\'itamin A 



Axerophthol (vitamin Ai) 



Carotene 

 Obsolete names : Fat-soluble A 



Biosterol 



Ophthalamin 



Anti-infective vitamin 

 Empirical formulas: Vitamin A: C20H30O 



/3-Carotene: C40H66 

 Chemical name : 3 ,7-Dimethyl-9-(2 ,6 ,6-trimethyl-2-cyclohexen-l-yl)- 



2 ,4 ,6 ,8-nonatetraen-l-ol 

 Structures: 



H3C 



H; 

 H. 



CH 



CH3 CHj 



I I 



CH=CH— C=CH— CH=CH— C=CH— CH2OH 



H2 CH3 



CH3 



CH3 



H 



6 

 26 1 



'4 2 



Vitamin A 



CH3 CH3 



I I 



I— CH=CH— C=CH— CH=CH— C=CH- 



H2 CH3 



CH3 CH3 



I I 



-CH=CH— CH=C— CH=CH— CH=C— CH=CH 



CH3 



H,ci?4'' 



CH, 



H2 

 H2 



H, 



/3-Carotene 



