464 V. CHEMISTRY OF PHOSPHATIDES AND CEKEBKOSIDES 



c. Dihydrosphingosine. Dihydrosphingosine, CH3(CH2)i4CHOH-- 

 CH(NH2) -CH-OH, is formed by the hydrogenation of sphingosine in the 

 presence of colloidal palladium according to the method of Carter and 

 Norris.^'''' It forms derivatives similar to those of sphingosine, i.e., sulfate, 

 triacetate,'** picrolonate, and picrate. Earlier analyses indicated that this 

 molecule had 17 carbons, but the more recent work of Klenk^'^ with the 

 picrate and bromide yields results which are in harmony with a Cis struc- 

 ture. Klenk ^'^ found that, on oxidation with chromic acid, palmitic acid 

 was produced, instead of pentadecyclic (w-pentadecanoic) as found by 

 Levene and West.'^'''^'^ Klenk based his identification on the melting 

 point (60-61°C.) and the titration value of the isolated acid. The presence 

 of dihydrosphingosine in the larval form (Cysticercus fasciolaris) of the cat 

 tapeworm has been demonstrated by Lesuk and Anderson. '^^'^ This would 

 indicate that it is a normal product. Although earlier workers failed to 

 find any of the dihydro-compound associated with sphingosine in nerve tis- 

 sue or brain, Carter and Norris'** have been able to prove that it is a nor- 

 mal constituent in such tissues. Carter and his associates'*^ found that 

 the concentration of the dihydrosphingosine is considerably higher in the 

 spinal cord than in the brain. Although it would seem probable that it 

 may be a component of the sphingomyelin molecule, there appears to be 

 definite evidence that it occurs in the cerebroside fraction, as it was shown 

 to be present in the phosphatide-free portion. 



A number of other related compounds can be prepared from sphingosine. 

 These include sphingamine, an luisaturated base with the formula C18H37N, 

 which is produced on reduction of sphingosine with hydrogen iodide. It 

 forms a sulfate with the composition (Ci8H37N)2-H£S04.'*^ Sphingine is an 

 amino alcohol with the suggested formula Ci7H34(OH)(NH2),'^^''*® which is 

 formed when the reduction with hydrogen iodide occurs in acetic acid. 

 When sphingosine is deaminized on treatment with nitric acid, dihydro- 

 sphingosol, Ci7H35(OH)3, is formed. '*« It melts at 54-55°C. On treat- 

 ment with methyl iodide in the presence of silver oxide, only one hydroxyl 

 group is methylated; the compound corresponds to the methylated am- 

 monium base of monomethyldihydrosphingosine.'^'' 



d. Lignoceryl Fatty Acid Esters and Synthetic Ceramides. Reichel 

 and Thannhauser'^" succeeded in preparing a number of esters of ligno- 

 cerylsphingosine, as well as some new ceramides. When sphingosine was 

 treated with the acyl chloride of the fatty acid, it was possible to introduce 

 three fatty acid residues into sphingosine — two in ester linkages on the hy- 

 droxyl groups and the third into the amino group. Since the esters are 



3" H. E. Carter and W. P. Norris, J. Biol. Chem., 145, 709 (1942). 

 3« H. E. Carter, W. P. Norris, F. J. Glick, G. E. Phillips, and R. Harris, J. Biol. Chem., 

 770,269-283 (1947). 



a^s P. A. Levene and C. J. West, J. Biol. Chem., U, 03-68 (1916). 

 3« E. Klenk and R. Harle, Z. physiol. Chem., 178, 221-238 (1928). 



