HYDROCARBONS 401 



zooplanktons examined. It would thus appear that squalene has a re- 

 stricted distribution in marine forms and that it is not even an invariable 

 constituent of the liver oils of the Elasmobranchii. Andre and Bloch,'*^'* how- 

 ever, reported that the liver oil of "Darkie Alf" {Dalatias licha), also known 

 as Kanatsubo-zame, contained as much as 57% of squalene compared with 

 a total triglyceride content of 21.7% and a glyceryl ether percentage of 

 21.3%. Strangely enough, squalene has been reported in one plant oil. 

 Thorbjarnarson and Drummond''*' found that the non-saponifial)le extract 

 of Palestinian, Tunisian, Spanish, and Turkish olive oils contained 64, 38, 

 31, and 58% of this hydrocarbon, respectively. However, because of the 

 relatively insignificant proportion of the non-saponifiable extract in olive 

 oil, the total squalene content is obviously quite small. No squalene was 

 found in teaseed oil,^^^ but Taufel et aZ.^^^ have sho\vn that it is present in 

 yeast fat to the extent of 16.3%. Fitelson*^^ has recently proposed a 

 method for the detection of olive oil based on a chromatographic separation 

 of squalene. 



Tsujimoto"*-^ first assigned what we now know to be the correct em- 

 pirical formula, C30H50, to this hydrocarbon. It was also found to be 

 identical with a hydrocarbon, spinacene,'*-^"* which had previously been 

 isolated from Portuguese shark-liver oil, or "barrosa," from either Centro- 

 phorus granulosis or Scymnus lichia.'^^^'^^^ The original formula proposed 

 by Heilbron, Owens, and Simpson*^® and by Heilbron and Thompson'*" 

 was later slightly modified ))y Karrer and Helfenstein^^^ on the basis 

 of their successful synthesis of this substance from farnesyl bromide 

 and activated magnesium. The structural formula suggested by Karrer 

 and Helfenstein,"*^^ which best explains the synthesis and other known reac- 

 tions, is as follows: 



:A . I CH_ CH, CH, Cn_ -, , , 



-CrCHCHjCHjClCHCHjCH^C'CHCHjCH^CHjCCHjCHjCHtCCHj CH2CH;C<r 



Squalene 



Squalene forms a series of addition products with halogens, such as the 

 hexachloride (CsoHsoCle, m.p., 110-125°C.), the hexabromide (CaoHsoBre, 

 m.p., 115-126 °C.), and the dodecabromide (CsoHjoBrio, m.p., 176-177°C.). 

 On hydrogenation it yields a saturated hydrocarbon, C30H62, which is a 

 liquid boiling at 274 °C. Squalene also combines to produce a hexaozonide 



"1 T. Thorbjarnarson and J. C. Drummond, Analyst, 60, 23-29 (1935). 



"2 K. Taufel, H. Thaler, and H. Shreyegg, Z. Uniersuch. Lebensm., 72, 394-404 (1936). 



«" J. Fitelson, J. As&oc. Official Agr. Chem., 28, 282-289 (1945); 29, 247-248 (1946). 



"* A. C. Chapman, J. Chem. Soc, 111, 56-69 (1917). 



*^ A. C. Chapman, /. Chem. Soc, 113, 458-466 (1918). 



*^ I. M. Heilbron, W. M. Owens, and I. A. Simpson, /. Chem. Soc, 1929, 873-883. 



"' I. M. Heilbron and A. Thompson, /. Chem. Soc, 1929, 883-892. 



"« P. Karrer and A. Helfenstein, Helv. Chim. Acta, I4, 78-85 (1931). 



