290 CAROTENOID CARBOXYLIC ACIDS XIII 



point 165° "'''. The nitrile is readily soluble in chloroform, benzene and hot 

 methanol and sparingly soluble in cold methanol, petrol and petroleum ether. 



Solvent Absorption maxima 

 Carbon disulphide 413 vn.^ 



Mono-amide C-^^^iriy^O^ : 



The amide is formed by boiling the methyl ester nitrile with potassium 

 hydroxide"''. It crystallises from methanol in yellow prisms, m.p. 256-257°. 



2:y-Dimethylnonatetraen-i-al-g-carboxylic acid methyl ester ("azafrinal-II" methyl 

 est^r) QaHieOj (III) : 



CH3 ^113 



OCH- C=CHCH=CHCH=C- CH=CH- COOCH3 

 III 



This compound is formed besides other products during the chromic acid 

 oxidation of azafrin methyl ester"^. It is purified by repeated chromatography 

 on alumina. It crystallises from 70 % methanol in light yellow prisms, m.p. 106°. 



It forms an oxime, CigHj^OgN, which crystallises from dilute methanol in 

 light yellow prisms, m.p. 194° "^. 



Perhydroazafrin methyl 'ster C28H54O4 : 



KuHN, WiNTERSTEiN and RoTH^^ prepared this perhydroester by the 

 catalytic hydrogenation of azafrin methyl ester. Colourless, viscous oil, b.p. 

 i8o-200°/i mm. [a]^° = —9.0° (in ethanol). 



Azafrin ethyl ester C29H42O4 : 



Azafrin ethyl ester is obtained by esterification of azafrin with diethyl 

 sulphate^^". It crystallises from ethanol in red prisms, m.p. 182° (corr., with 

 decomposition) . 



REFERENCES 



1. J. B. BoussiNGAULT, Ami. Chim. (2) 28 (1825) 440. 



2. Cf. Wehmer, Pftanzenstoffe, 2nd edition, vol. 2, 796. — F. Czapek, Biochemie, 2nd ed. 

 vol. 3, 576. — Karnot, Dissertation, Leipzig 1849; Jahresber. 1849, 457. — K. G. 

 ZwicK, Ber. 30 (1897) 1972. — L. Marchlewski and L. Matejko, Anz. Akad. Wiss. 

 Krakau, 1905, 745. — J. F. B. van Hasselt, Chem. Weekbl. 6 (1909) 480; Rec. 30 

 (191 1) 1,33 (1914) 192. — A. HEiDUSCHKAand H. Riffart, Arch. Pharm. 249 (igii) 4^. 



3. C. Etti, Ber. 11 (1878) 864. 



4. A. Heiduschka and A. Panzer, Ber. 50 (1917) 546 and 1525. 



5. R. KuHN and co-workers, Helv. chim. Acta 11 (1928) 427; 12 (1929) 64; Ber. 64 (1931) 

 1732; Helv. chim. Acta 12 (1929) 904; Ber. 65 (1932) 646; 65 (1932) 1873. 



6. P. Karrer and co-workers, Helv. chim. Acta 15 (1932) 1218, 1399. 



7. Cf. L. Zechmeister, Carotinoide, Berlin 1934. 



8. A. Heiduschka and A. Panzer, Ber. 50 (1917) 546, 1525. 



