THE SPHINGOMYELINS 463 



tablish their composition would have been to include nitrogen, as well as 

 CI, Br, or OCH3, when applicable. The data on the composition of various 

 sphingosine preparations upon which Klenk has based his conclusions are 

 summarized in Table 10. 



Carter ei al.^^^ have demonstrated that the revised formula for sphingo- 

 sine based on 18 carbon atoms should be modified by changing the assigned 

 positions of the hj'droxyl groups to carbons 1 and 3, rather than to 2 and 3 

 as proposed by Levene and West. This revision would seem imperative to 

 explain the fact that benzoylsphingosine will not react with periodate, but 

 rather forms a cyclic acetal with benzaldehyde in the presence of zinc chlo- 

 ride. In view of the fact that periodate will react only with vicinal glycols, 

 while acetal formation will occur with both 1,2 and 1,3 glycols, the above 

 results would seem to justify the assignment to sphingosine of the Carter 

 et aZ.*^- formula given hero. 



HO H 

 CH3(CH2),2CH=CH-C-C-CH20H 



" NH3 



Sphingosine 



Sphingosine is a component not only of sphingomyelin but also of the cere- 

 brosides (see Section B,2). Shimizu^^" reported the presence of sphingosine 

 in the urine after the administration of the cerebroside phrenosine to a dog. 

 Klenk is of the opinion that this finding has not been sufficiently established 

 to render it certain. 



Sphingosine can be crystallized from diethj-l ether. It readily separates 

 from petroleum ether in needle-like crystals. Sphingosine is easily soluble 

 in acetone, ethyl alcohol, and methjd alcohol, but is insoluble in water. 

 On oxidation it gives an odor of burning fat. Several well-defined deriva- 

 tives of sphingosine are knowii. Sphingosine sulfate, C]8H37N02-H2S04, 

 can be crystallized from hot alcohol in rosettes which consist of needles 

 arranged in a radial formation. It melts at 240-250°C. and is very hydro- 

 scopic. It dissolves in alcohol having a slight excess of sulfuric acid. 

 Sphingosine sulfate exliibits optical activity, its solutions being levo-rota- 

 tory, [a]l° = -13.12° (chloroform) ^'^S' [af^ = -9.47° (methyl alcohol 

 containhig H2S04).^^- Other derivatives include the diacetate (C18H37NO2- 

 (C2H402)2), the picrolonate (Ci8H37N02-CioH8N405}, and the triacetyl 

 derivative (Ci8H34N02-(CH3C0J3). The last compound melts sharply at 

 100°C. and it does not react with nitrous acid.^^^-^" A diacetyl derivative 

 has also been reported by Levene and Jacobs. ^^^ 



3« T. Shimizu, Biochem. Z., 117, 263-265 (1921). 



'" P. A. Levonn and W. A. Jacobs, ,/. Biol. Chem., 11, 517-554 (1912). 



»« O. Rosonhoiin, Biochem. J., 10, 142-1.39 (1916). 



3" K. Thomas and II. Thicrfcldcr, Z. physiol. Chem., 77, 511-515 (1912). 



