Formation of Lysosulfatide, 3', 6'-Anhydropsychosine, Ceramide, and Sphingosine by Saponification of Cerebroside Sulfate

Effect of the Sulfate Group on the Hydrolysis

Abstract

Saponification of cerebroside sulfate (sulfatide) by refluxing with 1 N KOH in 90% n-butanol for 1h yielded ceramide, sphingosine, lysosulfatide (psychosine-3'-sulfate ester) and a hitherto unknown compound. The latter compound was identified as 3, 6-anhydrogalactosyl sphingosine (3', 6'-anhydropsychosine) from its mass spectrum. The structure of lysosulfatide was confirmed by reacylating it to sulfatide by condensing it with lignoceroyl chloride. The resulting sulfatide, which was chromatographically identical to control sulfatides, was not oxidized by periodate. The sulfatide was also permethylated and methanolyzed. The sugar moiety obtained was identified as methyl 2, 4, 6-tri-O-methylgalactoside by gas-liquid chromatography and thin-layer chromatography. The presence of the sulfate group in lysosulfatide was further confirmed by IR spectroscopy and the presence of radioactivity when it was prepared from [³⁵S]sulfatide. The effect of the sulfate group on cleavage of the galactoside linkage and on the formation of the 3, 6-anhydro derivative is discussed.