Convenient Large-Scale Synthesis of D-Glucaro-1,4:6,3-dilactone

Calcium D-glucarate was converted into D-glucaro-1,4:6,3-dilactone on 32-g, 1-kg, and 22-kg scale, using azeotropic distillation with methyl isobutyl ketone to drive the dehydration. The crystalline product was >= 99.5% pure by GC and NMR, and overall yield was its high as 72%.