3o8 CAROTENOIDS OF UNCERTAIN STRUCTURE XIV 



9. APHANIZOPHYLL* 



The chemical constitution of aphanizophyll is still unknown. The pigment con- 

 tains a hydroxy! group which can be esterified and a carbonyl group which reacts 

 with hydroxylamine. Elementary analysis, however, gave very low values for the 

 carbon content (C, 70.15 %; H, 9.42 %), so that no conclusions regarding the 

 structure of the pigment can be drawn on the basis of the analytical results. 

 TiscHER^^ points out the similarity between aphanizophyll and myxoxantho- 

 phyll^^, but does not regard the two pigments as identical. 



Properties 



Crystalline form: The phytoxanthin crystallises from methanol in prismatic 

 crystals combined in rosettes. From pyridine it is obtained in circular, finely 

 tufted crystals. 



Melting point: 172-173° corr. 



Solubility: Aphanizophyll dissolves readily in pyridine and ethanol and 

 somewhat less readily in acetone, ether and acetic acid. It is completely 

 insoluble in benzene, petrol and carbon disulphide. 



Optical rotation: No data have been recorded. 



Spectral properties: 



Solvent Absorption maxima 



Pyridine . . , ..... . . 531 494 462 m/j. 



Chloroform 523 487.5 457 m/x 



Methanol 507 475 444 m/n 



Solutions of the pigment in methanol are yellow, solutions in chloroform 

 deep red, and solutions in pyridine blood-red. 



Partition test: Aphanizophyll is entirely hypophasic on partition between 

 petroleum and methanol. 



Chromatographic behaviour: Aphanizophyll is adsorbed so strongly on alumina 

 and calcium hydroxide that it is almost impossible to elute it. It is also readily 

 adsorbed on calcium carbonate or sodium sulphate from chloroform or ether 

 solution but can be completely eluted with methanol. 



Colour reactions: A solution of aphanizophyll in chloroform shows the follow- 

 ing colour reactions. Concentrated sulphuric acid produces a blue colour. 

 Concentrated nitric acid gives a blue colour which changes to green and 

 eventually fades. Antimony trichloride in chloroform gives a blue colour which 



* For the isolation of this pigment, see under aphanin, p. 301. 

 References p. 241-343- 



