The reaction of chlorodeoxyephedrine hydrochlorides with one, two, and three molar equivalents of base was studied. Isochlorodeoxypseudoepherines were identified and assigned by 1H and 13C NMR data as intermediate compounds in the formation of cis-aziridines. Erythro and threo ephedrinethylethers were isolated as new compounds and analyzed by spectroscopic data. In addition, the erythro isomer was studied by X-ray diffraction. © 2010 Elsevier Ltd. All rights reserved.