Synthesis of sphingomyelin sulfur analogue and its behavior toward sphingomyelinase

The sulfur analogue of sphingomyelin was designed and stereoselectively synthesized from S-benzyl-N-Boc-cysteine. The introduction of the phosphoryl choline moiety was successfully achieved by our own method using 2-bromoethyl dimethyl phosphite and carbon tetrabromide followed by a trimethylamine treatment. The synthesized compound proved to be a useful substrate for monitoring the enzyme activity of sphingomyelinase by detecting the liberated thiol group with a thiol-sensitive reagent.