580 VI. CAROTENOIDS AND RELATED COMPOUNDS 



HjC CHj 

 \ / 



C H,C CHj 



u n f ^-^^ pCHs CH3 CH3 CH3 p 



H.| I iIhhhIhhhhIhhhIhh /\ 



C C C— C: C • C: C- C: C • C: C- C; C • C: C • C: C • C: C- C = CH? 



HO C i I /" 



OH 



H, C CHs C 



H3 / \ / \ 



H3C c 



Hj 



Capsophrome 



The epoxide, capsochrome, and capsanthin are readily distinguished from 

 each other by their absorption spectra. The following are the absorption 

 peaks in m/x, using carbon disulfide as the solvent: capsanthin, 542, 503; 

 capsanthin epoxide, 534, 499; capsochrome, 513, 482. 



(13) Capsoruhin 



In 1930, Zechmeister and Cholnoky,^^* by the use of a chromatographic 

 separation, isolated a second pigment from Capsicum frutescens (paprika) , 

 in addition to capsanthin. This violet-red chromogen was named "cap- 

 soruhin." To date it has been found only in the paprika. Capsorubin 

 has nine double bonds instead of the ten found in capsanthin ; there are two 

 alcohol groups and four methyl side chains and no isopropylidine groups. 

 Apparently it is a diketone, since it has four oxygens ; it has an absorption 

 spectrum which compares quite closely with that of bixin dialdehyde. The 

 marked difference between the positions of the absorption maxima in 

 petroleum ether and in alcohol also argues in favor of the diketone struc- 

 ture. The empirical formula of capsorubin is C40H60O4. On the basis of 

 these data, capsorubin has been assigned the structure shown here.^^^-^^'^ 



HjC CH3 H,C CHj 



r CHj CH3 CH3 CH3 p 



/\ hhIhhhIhhhhIhhhIhh /\ 



HzC 0=C-c:c-c:C'C:c*c:C'C:C'C:C-C:C'C:c-C:C'C=0 CHz 



H\l l/H 



C CH2 CH, C 



/\/\ /\/\ 



HO C CH3 HjC C OH 



H2 hi 



Capsorubin 



{14-) ^-Citraurin 



Zechmeister and Tuzson^^^-^^^ first noted the presence of an unknown pig- 

 ment in Seville orange peels {Citrus aurantium) in addition to carotene, 

 cry ptoxan thin, zeaxanthin, lutein, and violaxanthin. They called it 



375 L. Zechmeister and P. Tuzson, Ber., 70, 1966-1969 (1937). 



