394 IV. WAXES, HIGHER ALCOHOLS, ETC. 



it was fairly simple to establish the formula for selachyl alcohol as C2iH420;i. 

 Although Toyama proved that selachyl acetate gave rise to oleyl alcohol on 

 dry distillation, the decision as to the nature of the third oxygen atom 

 awaited the experiments of Weidemann.^"* He found that hydroidic acid 

 acts on batyl alcohol to produce methyl iodide. This proves that the third 

 oxygen is present in a methoxy group, which fact indicates that an ether 

 linkage exists between palmityl (cetyl) alcohol and the glycerol. 



A number of experimental observations indicate that the connection be- 

 tween these higher alcohols and glycerol occurs through the a-hydroxyl 

 group of the triatomic alcohol. In the first place, the proof was obtained 

 by synthesis of the a-ether of glycerol and stearyl alcohol and by compari- 

 son of the synthetic with the natural product. To accomplish this, octa- 

 decyl iodide, CH3(CH2)i6CH2l, was condensed with sodium allyl oxide to 

 form the octadecylallyl iodide.^* The latter compound when oxidized 

 with perhydrol gave a-octadecylglyceryl ether. This ether had the same 

 melting point (70-71 °C.) as natural batyl alcohol. However, it did show a 

 slight but definite depression in melting point when mixed with the natural 

 product. That this does not indicate that the natural product is a ;S-ether 

 was shown by the fact that the /S-octadecyl glyceryl ether (m.p., 62-63 °C.) 

 showed a considerable depression in melting point when mixed with 

 natural batyl alcohol. ^""^ Similar variations were noted between the syn- 

 thetic j3-cetyl glyceryl ether and natural chimyl alcohol. The j3-ethers 

 were synthesized by a condensation of a, a'-benzylidene glycerol with 

 octadecyl or cetyl iodide followed by hydrolysis of the resulting product. 

 Further proof that natural glyceryl ethers were the a-forms was afforded 

 by the demonstration that the surface film activity of the natural product 

 was identical with that of the a-ether, and that it showed marked variations 

 from that exhibited by the synthetic /3-form.^^'^"^ 



A third experimental finding also confirms the fact that an a-ether exists 

 naturally. On oxidation of batyl alcohol with lead tetraacetate, which, 

 according to Criegee,''"^ is a reagent specific for an a,/3-glycol, glycol alde- 

 hyde octadecyl ether (m.p., 51 °C.) and fonnaldehyde were obtained.^"** 

 This reaction indicates that the a.'- and |S-positions must have been free and 

 leaves no alternative to the supposition that the glyceryl ethers are a- 

 ethers. 



Finally, the optical properties furnish further evidence that the com- 

 bination must be an asymmetric one. Although Toyama^^^ originally did 

 not observe optical activity, the free alcohol was later shown to possess this 



«4 G. Weidemann, Biochem. J., 20, 685-691 (1926). 



«= G. G. Davies, I. M. Heilbron, and W. M. Owens, /. Chem. Soc. , 1930, 2542-2546. 

 ^06 W. H. Davies, I. M. Heilbron, and W. E. Jones, J. Chem. Soc, 1933, 165-167, 

 1934, 1232-1235. 



*«^ B. C. J. G. Knight, Biochem. J., 24, 257-201 (1930). 

 «8 R. Criegee, Ber., 64, 260-266 (1931). 



