p-CAROTENE 



133 



Further confirmation of the /3-carotene formula was provided by the in- 

 vestigations of KuHN and Brockmann^^ in which /3-carotene was related to 

 azafrin through mild stepwise degradation reactions. 



CH3 CH, CH3 CH3 



\V \/ 



A r r r r a 



CH2 C-CH=CH-C=CHCH=CH-C=CHCH=CHCH=C-CH=CHCH=C-CH=CH-C CHj 



CH2 C'CHj a^Kj' Kj vyH2 



\ / /3-Carotene A / 



CH2 CH2 



CrO, 



CH3 CH3 



\/ 



C 



I 



CH, 



CH, 



CH3 



CH, 



CH3 CH3 



\/ 

 C 



CHj C-CH=CH-C=CHCH=CH-C=CHCH=CHCH=C-CH=CHCH=C-CH=CH-C CH^ 



I II KO^I I 



CH2 C-CHj H0\| I 



A A Dihydroxy-)9-carotene HaC-C CHj 



CHj, \A 



Pb(OCOCH3)4 



CH3 CH3 CH3 CH3 



\A ^ \A 



C CH3 CH3 CH3 CHs C 



A\ I I I I A\ 



CHa C-CH=CH-C=CHCH=CH-C=CHCH=CHCH=C-CH=CHCH=C-CH=CH-CO CHj 



CHj C-CH3 HjC-CO CHa 



\ / Semi-)3-carotenone A A 



CHa CH, 



CrO, 



CH, CH, 



\/ 



C 



^ 



CH, 



CH, 



CH, 



CH, 



CH3 CH, 



\/ 

 C 



CHa C-CH=CH-C=CHCH=CH-C=CHCH=CHCH=C-CH=CHCH=C-CH=CH-CO CHa 



I |\0H I 



I I/OH 



CHo C' CH, 



CHa 



CH3 CH, 

 C 



Dihydroxysemi-^-carotenone 

 Pb(OCOCH3)4 



CH, 



CH, 



HaC-CO CHa 

 CHa 



CH3 CH, 



\/ 

 C 



Clio CHq 



/\ r I I I ■ A\ 



CHa CO-CH = CH-C=CHCH=CH-C=CHCH=CHCH=C-CH=CHCH=C-CH=CH-CO CHa 



CHa CO-CHs H3C-C0 CHj 



A A /5-Carotenone A A 



CHa CHa 



References p. 165-170. 



