Several substituted oxazolidines of sphingosine and dihydrosphingosine were prepared by condensation with benzaldehyde to form the N-benzylidene derivative, after which ring closure was effected by reaction with the appropriate acyl chloride in aqueous alkali and ether. The formation of the oxazolidine ring involved the hydroxyl group on carbon atom 3 of sphingosine or dihydrosphingosine without change in configuration. An oxazolidine ...