4 ZEAXANTHIN 189 



Neo-zeaxanthin A: Small plates from methanol, m.p. about 106° (not sharp, 

 corr.). 



Solvent Absorption maxima: 



Carbon disulphide 508 475.5 m/i 



Benzene 489 457.5 m^ 



Petrol 477 447 m/z 



Ethanol 478.5 448.5 m/z 



[a]j. about +120" (in chloroform). 



Neo-zeaxanthin B: Flat, obliquely cut plates, from dilute methanol, m.p. 92° 

 (not sharp, corr.). Absorption maxima in carbon disulphide, benzene, petrol and 

 ethanol are the same as for neo-zeaxanthin A. The optical rotation shows varying 

 values. 



Neo-zeaxayithin C: Small crystals from a mixture of carbon disulphide and 

 benzene. M.p. 154° (corr.). 



Solvent: Absorption maxima: 



Carbon disulphide 502 470 m/i 



Benzene 488.5 455 m/i 



Petrol 473.5 444 m^ 



Ethanol 473 443.5 m// 



Epoxides of Zeaxanthin and their Transformation Products 



By the oxidation of zeaxanthin acetate with monoperphthaUc acid, Karrer 

 and JuCKER^'' obtained various epoxides and furanoid transformation products 

 some of which proved to be identical with natural carotenoids, the structure of 

 which had previously been unknown. As the natural oxides of zeaxanthin are 

 dealt with in detail in the following chapter only a brief description of these 

 compounds will be given here. 



a) Zeaxanthin mono-epoxide, Antheraxanthin* : 



CH, CH, CH, CH, 



CHo CH.> oHo CHo C 



I I I I /\ 



CH^ C-CH=CH-C=CHCH=CH-C=CHCH=CHCH=C-CH=CHCH=C-CH=CH-C CHg 



HsC-C CHOH 



HOCH C \ / 



\/\ Antheraxanthin CHj 



A detailed description of this pigment will be found on p. 191. 



Antheraxanthin was first isolated by P. Karrer and A. Oswald from anthers of 

 Lilium tigrinum, Helv. chim. Acta 18 (1935) 1303. 



References p. 214— 21J. 



