134 CAROTENOID HYDROCARBONS OF KNOWN CONSTITUTION X 



CrO, 



CHo CH 



\V 



C 



CH, CH, 



CH3 CH3 CH3 C 



/\ I I I /\ 



CH. CO-CH=CH-C=CHCH=CH-C=CHCH=CHCH=C-CH=CHCHO+HOOC CH, 



CH, CO-CH, 



\/ 



CHj 



CH3 CHa 



c 



/3-Carotenone aldehyde 



NH2OH 



i 



HjC-CO CH, 

 CH, 



CH, 



/\ r 1 I 



CH2 CO- CH=CH- C=CHCH=CH- C=CHCH=CHCH=C- CH=CH- CH=NOH 



I 



CH, CO-CH, 



CH2 

 CH, CHo 



\/ 



C 



/3-Carotenone aldehyde monoxime 

 (CH3C0)20 



CH, CH, CH, 



/\ I I I 



CH2 CO- CH=CH- C=CHCH=CH- C=CHCH=CHCH=C- CH=CH- CN 



CH, CO-CH, 



Nitrile 



CH2 

 CH, CH, 



\/ 



C 



KOH 



CH, 



CHo CHo 



/\ r I 1 



CH2 C- CH=CH- C=CHCH=CH- C=CHCH=CHCH=C- CH=CH- CONH2 

 CH2— C- CO- CH3 Anhydroazafrinone amide 



As anhydroazafrinone amide can also be obtained from azafrin via azafri- 

 none amide the relation between /5-carotene and azafrin is established. (For 

 the individual compounds involved in these reactions see p. 284). 



Formation 



P. Karrer and E. Jucker^^ obtained /5-carotene by the action of sodium 

 ethoxide on a-carotene. Up to the present time this is the only way in which 

 this pigment has been obtained synthetically*. 



P. Karrer and S. Schwyzer, Helv. Chim. Acta 31 (1948) 1055, have recently 

 described the formation of traces of a carotenoid pigment, probably /3-carotene, in the 

 reaction of vitamin A ^-toluenesulphonic ester and sodium iodide in acetone. The main 

 product is anhydro-vitamin A. 



References p. 165-iyo. 



