Dehydration of Some Hexitols

ABSTRACT Heating galactitol, D-glucitol, D-mannitol and L-iditol in a 5% aqueous sulfuric acid solution at 200 °C for 30 min afforded 1, 4-, 3, 6-, 1,5-, 2,6- and 1,6-monoanhydrohexitols with retained configuration as well as 2,5-monoanhydrohexitols with inverted configuration at C-2 or C-5. 1, 4;3,6-, 1,5;2,6- and 1,4;2,6- s 1,5;3,6-Dianhydrohexitols were also identified. Cyclization of the hexitols via their O-tosyl derivatives in pyridine gave products completely free of 2,5-anhydrohexitols but with increased amounts of dianhydrohexitols. All mixtures were separated by capillary GC (CGC) and their components identified by CGC-MS and by co-injection with standards.