Non-catalytic synthesis of 4-O-β-2-acetamido-2-deoxy-D-glucopyranosyl 2-acetamido-2,3-dideoxydidehydro-glucopyranose (GND) from chitin disaccharide, N,N′-diacetylchitobiose (GlcNAc)₂, was achieved, with a maximum yield of 24.7% in high-temperature water at 120–220 °C and 25 MPa with a reaction time of 8–39 s.