Synthesis of dl‐erythro and threo‐sphingosine‐4,5‐ 3 H

DL‐erythro‐sphingosine and DL‐threo‐sphingosine specifically labelled with 3 H in positions 4 and 5 were prepared. The synthesis of these compounds was based on a modification of a procedure published by Grob and Gadient. Quantitative separation of the sphingosines from acetylenic impurities was accomplished, and the physical constants of pure DL‐erythro and threo sphingosines were determined. D‐erythro sphingosine was prepared by resolving the DL racemate and it was found identical to the naturally occurring product.