I LYCOPENE 123 



Apo-3-lycopenal C30H4PO: 



OHC- C=CHCH=CH- C=CHCH=CHCH=C- CH=CHCH=C- CH=CHCH=C- CH2CHi,CH=C- CH, 



11 I I I I 



CH3 CH3 CH3 CH3 CH3 CH3 



Apo-3-lycopenal was obtained by Karrer and Jaffe*^ by the mild oxid- 

 ation of lycopene with potassium permanganate. It separates from petroleum 

 ether in brown-black crystals, m.p. 138°. 



Solvent: Absorption maxima: 



Carbon disulphide 545 508 ca. 478 van 



Petrol 502 473 m/z 



Benzene 518 488 m/z 



Apo-2:i2-lycopenedial (bixindialdehyde) C^JA^^O^'. 



OHC- CH=CH- C=CHCH=CH- C=CHCH=CHCH=C- CH=CHCH=C- CH=CH- CHO 



Cri3 ^H3 VXI3 ^^13 



Bixindialdehyde is formed by the oxidation of lycopene or lycopenal (apo-2- 

 lycopenal) with chromic acid*^. It crystallises from pyridine in lustrous blue 

 prisms, m.p. 220° (corr.). On heating in air, it decomposes at 180° ^vithout 

 melting. Bixindialdehyde is appreciably soluble in pyridine and chloroform, 

 and sparingly soluble in hot benzene, but only dissolves with great difficulty in 

 petrol, alcohols, carbon disulphide, ether, acetone, or dioxan. 



Solvent: Absorption maxima: 



Carbon disulphide 539.5 502 467.5 m/x 



Petroleum ether 502 468 437.5 m^i 



Pyridine 534.5 494 m^u 



Chloroform 528 490 m/i 



(cf. Fig. 17, p. 355) 



Bixindialdehyde dioxime crystallises from pyridine in needles which de- 

 compose above 250° without melting*®. It is soluble only in pyridine. 



Solvent: Absorption maxima: 



Pyridine 514 482 452 m^ 



Apo-3:i2-lycopenedial (apo-1-bixindialdehyde) CgaHjeO.^,: 



OHC- CH=CH- C=CHCH=CH- C=CHCH=CHCH=C- CH=CHCH=C- CHO 



CH3 CH3 CH3 CH3 



Apo-i-bixindialdehyde was obtained by Karrer and Jaffe by the chromic 

 oxidation of lycopene*'. It separates from methanol in dark crystals, m.p. 168° 

 (uncorr.) . 



References p. 165-iyo. 



