Methyl 2,3,4-triacetamido-2,3,4,6-tetradeoxy-α-L-hexosides of gluco- and manno-configuration are obtained from methyl 2,4-di-O-acetyl-3-deoxy-3-nitro-α-L-rhamnoside in three steps, involving as the crucial stage a diamination with ammonia, the course of which is strongly dependent on the conditions used.