5 FLA VORHODIN 299 



rhodovibrio-bacteria, but it appears to have the molecular formula C4oH5g02 

 or C4(,H5g02. It is improbable that both oxygen atoms are present as hydroxyl 

 groups since rhodovibrin, like rhodopin, is epiphasic in the partition test. 

 Methoxyl determinations also gave a negative result. 



4. RHODOPURPURIN 



Rhodopurpurin occurs in rhodovibrio-bacteria in very small amounts and 

 was isolated from the latter by Karrer and Solmssen* by the procedure 

 described for the preparation of rho^pviolascin and rhodopin (pp. 295 and 297). 

 It is adsorbed below rhodopin in the chromatogram on calcium hydroxide and 

 is isolated by elution, dissolution in petroleum ether and concentration of the 

 solution. The pigment crystallises from petroleum ether in fine microscopic 

 needles which are partly combined in clusters and melt at 161-162°. Ultimate 

 analysis shows that the compound is probably a hydrocarbon of the formula 



^40^56 ^^ ^40^58- 



On partition between methanol and petroleum ether, rhodopurpurin is 

 entirely epiphasic. In its spectral properties it shows great similarity to lycopene ; 

 its identity with the latter is still uncertain, however. 



Solvent Absorption ynaxima 



Carbon disulphide 550 511 479 m/< 



Chloroform 527 487 (458)m// 



Petroleum ether 502 472 m/t 



Benzene 527 490 m/i 



5. FLAVORHODIN 



This pigment was also obtained by Karrer and Solmssen* from rhodo- 

 vibrio-bacteria. It is obtained from the lowest zones of the calcium hydroxide- 

 chromatogram in the preparation of rhodopin**. 



The constitution of flavorhodin is unknown. The pigment is easily soluble 

 in petroleum ether, benzene, chloroform acetone and ether, but only sparingly 

 soluble in ethanol and methanol. It is entirely epiphasic in the partition test. 



Solvent Absorption maxima 



Carbon disulphide 503 472 441 m/n 



Chloroform 482 453 m/z 



Petroleum ether 470 442 m/x 



Ethanol 471 443 m/u 



(cf. Fig. 27, p. 359) 



In its optical properties, flavorhodin is reminiscent of sarcinin (p. 319), 

 but the question of the identity of these two pigments is still unsettled. 



For a summary of the literature, see under rhodopin, p. 297. 

 ** Cf. p. 297. 



References p. 341-J4J. 



