3 ^-CAROTENE 143 



P-Carotenone aldehyde C27H35O3: 

 CHo CHo 



/\ ! I I 



CH2 CO- CH=CH- C=CHCH=CH- C=CHCH=CHCH=C- CH=CHCHO 



CHa CO-CHj 



\ ^ ^-Carotenone aldehyde 



CHjj 



This aldehyde is formed by the oxidation of /9-carotene or j5-carotenone 

 with chromic acid^^^. It crystalhses from a mixture of benzene and petrol in 

 yellow-red needles with a bluish lustre, m.p. 146-147° (corr. evacuated capil- 

 lary). The compound is readily soluble in chloroform, carbon disulphide, ben- 

 zene and hot methanol, but only sparingly soluble in cold petrol and petroleum 

 ether. 



Solvent: Absorption maxima: 



Carbon disulphide 491 459 430 m/^ 



Chloroform 482 450 423 m/x 



Petroleum ether 457 430 404 m^ 



Petrol 461 432 406 m/x 



Benzene 476 446 420 m[i, 



Hexane 458 431 405 mn 



Ethanol (473) (442) m/^ 



On prolonged treatment with excess hydroxylamine, /5-carotenone aldehyde 

 forms a dioxime. With regard to its constitution, compare Kuhn and Brock- 

 MANN^^^. It crystallises from dilute methanol in yellow-red plates, m.p. 183- 

 184°. It is sparingly soluble in petroleum ether, petrol and cold benzene, but 

 more easily soluble in ethanol. 



Solvent: Absorption maxima: 



Carbon disulphide 492 



Chloroform 478 



Petrol 462 



Benzene 477 



Using molecular proportions of hydroxylamine and |5-carotenone aldehyde^ 

 a monoxime is obtained which is a mixture of aldoxime and ketoxime. 



The monoxime crystallises from methanol in yellow-red plates or needles, 

 m.p. 174°. (Concerning the conversion of the aldoxime into anhydroazafrinone 

 amide, see p. 134 and Kuhn and Brockmann loc. cit.). 

 References p. 165-iyo. 



