3o6 



CAROTENOIDS OF UNCERTAIN STRUCTURE 



XIV 



Colour reactions: Aphanicin shows almost the same colour reactions as 

 aphanin. Table 53 shows the reactions which give different results. 



TABLE 53 



COLOUR REACTIONS DISTINGUISHING BETWEEN APHANIN AND. APHANICIN 



Physiological behaviour^^: Aphanicin exhibits about half the vitamin A 

 activity of aphanin. 



Detection and Estimation: Aphanicin can be separated from the other 

 carotenoids of Aphanizomenon flos-aquae by chromatographic adsorption and 

 is identified by means of its spectral properties and its colour reactions. 



Derivatives 

 Aphanicin oxime: 



Aphanicin oxime is prepared in the same way as aphanin oxime. M.p. 241° 



Solvent Absorption range Absorption maxima 



Carbon disulphide . 460-545 529 492 m^l 



Chloroform .... 450-520 504 474 m// 



Benzene 455-520 505 472 m/< 



Petrol b.p. 70-80° . 445-505 493 461 m/z 



Pyridine 460-525 508 478 m/z 



Methanol 445-505 491 456 mfi 



Aphanicol: 



This compound is prepared in the same way as aphanol^*. Aphanicol could 

 not be obtained crystalline. 



Solvent Absorption maxima 



Carbon disulphide 516 482 m/i 



Petrol 484 454 m/i 



References p. 341—343. 



