PSEUDOSUGARS .34. SYNTHESIS OF 5A-CARBA-BETA-D-GLYCOSYLCERAMIDE ANALOGS LINKED BY IMINO, ETHER AND SULFIDE BRIDGES

Carbocyclic analogs of glycoceramides, pyranosyl)-2-(hexadecanoylamino )-4-octadecen-3-ols E-3-E-6, linked by imino, ether and sulfide bridge s, were synthesized by coupling of aziridines, as the sphingosine prec ursors, with protected 1-amino, 1-hydroxy and 1-mercapto derivatives o f 5a-carba sugars and subsequent deprotection and N-acylation. Biologi cal assay of 5a-carbaglycosylceramides showed that both imino-linked E -3 and E-4 having gluco and galacto configurations are mild immunomodu lators and possess a mild inhibitory activity against gluco- and galac tocerebrosidases. These findings prompted us to prepare the correspond ing Z-isomers Z-3 and Z-4, which interestingly show a similar enzyme-i nhibitory activity.