The structure of methyl 4-amino-4-cyano-4,6-dideoxy-2,3-O-isopropylidene-α-Ltalopyranoside was established by X-ray analysis confirming a talo configuration at C-4 and suggesting a 1C4 conformation of the pyranose ring. The values of relevant torsion angles and calculated puckering parameters revealed a distortion into the direction of 5E conformation, thus indicating a flattening at C-2.