RELATED COMPOUNDS 



665 



isoprenic structure. The empirical formula is believed to be C40H64 ±2- 

 Accordingly, phytofluene is the first naturally occurring representative of 

 the C40 polyenes which is more saturated than are the common caroten- 

 oids."^ 



The most distinctive property of phytofluene is its spectral absorption in 

 the ultraviolet. Three maxima are found: at 331, 348, and 367 uifj.. 



E 

 »5o 



■ 



- Z ^ — : 



£ 



III 



300 

 WAVE LENGTH, m^l- 



300 



WAVE LENGTH, m/i. 



Fig. 30. Extinction curve of phytofluene Fig. 31. Extinction curve of piij^tofluene 

 in hexane.^'* in benzene.^'* 



Because of the location of these maxima it seems highly improbable that 

 more than 5 of the double bonds are conjugated. The extinction maximum 

 at 348 ran in hexane is almost identical with the maximum for vitamin A2 at 

 345 m/x. Karrer and Bretscher*^* assume that vitamin Ao has an entirely 

 open structure which contains one isolated and 5 conjugated double bonds. 

 A similar structure might be postulated for phytofluene, with the exception 

 that most of the molecule is saturated. The absorption curves of phyto- 

 fluene in hexane and benzene are included in Figures 30 -and 31. The 

 extinction values at the maxima and minima are included in Table 37. 



Phytofluene has an unusual reaction with antimony trichloride. A 

 transient blue color results which shows two bands (615 and 570 m/x). In 

 30 seconds it changes to a purple color and then to one resembling perman- 



53« P. Karrer and E. Bretscher, Helv. Chim. Acta, 26, 1758-1778 (1943). 



