PROPERTIES OF THE CAROTENOIDS 



627 



Table 21 



Numbers of cis-trans Isomers for Unsymmetrical and Symmetrical Chains 



Containing n Stereochemically Effective Double Bonds" 



» L. Zechmeister, Chem. Revs., 34, 267-344 (1944), p. 277. 



Table 22 



Calculated Number of Stereoisomers for Naturally Occurring Carotenoids 



AND for Some of Their Conversion Products" 



Unsymmetrical molecules'" 



Symmetrical molecules'' 



Pigment 



(1) 



(2) 



Pigment 



(1) 



(2) 



a-Carotene 



7-Carotene 



Cryptoxanthin 



Rubixanthin 



Gaxaniaxanthin 



Lycoxanthin 



Lutein 



Rhodoviolascin 



Capsanthin 



Seiui-/i-carotciione 

 a-Citrauriii 

 ^-Citraurin 

 Bixin 



Methylcrocetin 



Azafrin 

 Vitamin A 



/3-Carotene 

 LjTopene 



20 

 72 



32 



32 

 32 

 32 

 32 



32 



10 



4 



" L. ZochnuMstcr, Chan. Revs., 34, 267-344 (1944), p. 278. 

 '■Column (1): number of effective double l)onds. Column (2): 

 isomers. 



(•iilculated number of 



