CROCETIN 279 



CH3 CH3 CH3 CH3 



Br-CH2CHCH2CH2CH2CHCHaCH2CH2CHjjCHCH2CH2CH2CHCH2Br 



I 

 CH3 CH3 CH3 CH3 



HOOCx II II /COOH 



^CH • CHjCHCHjCHijCHaCHCHaCHaCHaCHaCHCHaCHaCHaCHCHaCH^ 

 HOOC/ \C00H 



CH3 CH3 CH3 CH3 



HOOC- CHjCHaCHCHjCHaCHjCHCHjCHjCHaCHzCHCHaCHjCHaCHCHaCHa- COOH 

 Perhydronorbixin (cf. p. 265) 



2:6:ii:i§-Tetramethylhexadeca7te (Crocetane) C20H42: 



Karrer and Golde prepared crocetane from i:i6-dibromo-2:6: 11:15- 

 tetramethylhexadecane by reduction with coppered zinc and dilute acetic 

 acidi3*. 



CH3 CH3 CH3 CH3 



H3C-CHCH2CH2CH2CHCH2CH2CH2CH2CHCH2CH2CH2CHCH3 

 Crocetane 



Crocetane is a colourless oil, b.p. i35°/o.5 mm. It is readily soluble in petro- 

 leum ether, chloroform and carbon disulphide and more sparingly soluble in 

 ethanol and acetic acid. 



6:ii-Dimethylhexadeca-3: 5:j:g:ii: i3-hexaeyi-2:iydicarboxylic acid. Dihydrucrocetin 

 C20H26O4 (I)': 



HOOC- CHCH = CHCH = C-CH = CHCH=CH-C=CHCH=CH-CH- COOH 



I 



Dihydrocrocetin was prepared by Karrer, Helfenstein and Widmer^^^ 

 by the reduction of crocetin with titanium ti ichloride in dilute sodium hydroxide 

 and aqueous ammonia. It crystallises from ether in stout yellow needles, m.p. 

 192-193°. It is readily soluble in ethanol and acetic acid, more sparingly soluble 

 in ether, and very sparingly soluble in water, ligroin and benzene. Dihydrocro- 

 cetin is rapidly oxidised in air. With concentrated sulphuric acid, a wine-red 

 colouration with a blue tinge is produced. Quantitative extinction measurements 

 in ethanol solution are reported by Hausser and Smakula^^® (cf. Fig. 21, p. 356). 

 References p. 290-2^4. 



