336 CAROTENOIDS OF UNCERTAIN STRUCTURE XIV 



xanthophyll, xanthophyll epoxide and another new carotenoid, also of epoxide 

 character. The latter was not obtained in sufficient quantity for more detailed 

 investigation. 



For the preparation of trollixanthin, the blossoms are dried at about 40° and 

 are exhaustively extracted with petroleum ether at room temperature. The combined 

 extracts are concentrated to a small volume in vacuum and the residue is saponified 

 with methanolic potassium hydroxide at room temperature. The pigments are 

 then separated into an epiphasic and a hypophasic fraction. The latter is repeatedly 

 boiled with ligroin to remove colourless products and the undissolved portion is 

 chromatographed on zinc carbonate. Trollixanthin is adsorbed on the upper part 

 of the column and can be separated from the less strongly adsorbed xanthophyll 

 epoxide. It is eluted with methanol-containing ether and is recrystallised from 

 benzene. 



The constitution of the pigment is still unknown. The molecular formula 

 of trollixanthin is C4{,H5g04^. Trollixanthin is a monoepoxide ; by the action of 

 dilute mineral acid it is converted into a furanoid derivative, trollichrome, the 

 absorption maxima of which are displaced by 22 m^i towards shorter wavelengths 

 (in carbon disulphide solution) . The remaining oxygen atoms are present in the 

 form of hydroxyl groups; the latter are responsible for the stronger adsorption 

 of trollixanthin as compared with xanthophyll epoxide on zinc carbonate. In 

 view of the close similarity in the spectral properties of trollixanthin and 

 xanthophyll epoxide, and of trollichrome, flavoxanthin and chrysanthema- 

 xanthin, it is probable that similar chromophoric systems are present. Trolli- 

 xanthin crystallises from benzene in thin, clustered light-yellow leaflets, m.p. 

 199° (uncorr., in vacuum). On shaking an ethereal solution of the pigment with 

 concentrated aqueous hydrochloric acid, the latter assumes a weak blue co- 

 louration, as in the case of most carotenoid monoepoxides. 



Solvent: Absorption maxima: 



Carbon disulphide 501 473 m^ 



Ethanol 474 447 m/x 



Benzene 483 457 m/z 



Chloroform . . . . 482 455 m/j. 



On partition between methanol and petroleum ether, trollixanthin is 

 entirely hypophasic. 



Trollichrome separates from benzene in light yellow crystals, m.p. 206-208° 

 (uncorr., in vacuum). The hydrochloric acid reaction and partition test are the 

 same as with trollixanthin, 



Solvent: Absorption maxima: 



Carbon disulphide 479 450 m/j. 



Ethanol 451 424 m/t 



Benzene 459 432 m/i 



Chloroform 458 430 m/j, 



References p. J41-J4J. 



