REACTION OF DICHLOROALLOSE UNITS IN A CHLORODEOXYCELLULOSE WITH LITHIUM-CHLORIDE UNDER HOMOGENEOUS CONDITIONS IN N,N-DIMETHYLACETAMIDE

The reaction of methyl 3,6-dichloro-3,6-dideoxy-beta-D-allopyranoside with lithium chloride in N,N-dimethylacetamide (DMA) was studied in relation to the possible conversion of 3,6-dichloro-3,6-dideoxy-D-allose units in a chlorodeoxycellulose during synthesis in a LiCl-DMA solvent system. Methyl 3,6-dichloro-3,6-dideoxy-beta-D-glucoside was formed; the reaction was reversible and the equilibrium was on the glucoside side. GLC analysis of the hydrolyzates of chlorodeoxycellulose samples after treatment with LiCl showed that the dichloroallose units were partly converted into 3,6-dichloro-3,6-dideoxy-D-glucose units. A kinetic study showed that the rate of conversion of the dichloroallose unit into the dichloroglucose unit was lower than that of the dichloroalloside into the dichloroglucoside, and the amounts of the two units at equilibrium were calculated to be close to each other. Based on the values of the kinetic parameters obtained, the conversion of the dichloroallose units into the dichloroglucose units during the chlorination of cellulose in LiCl-DMA was estimated to be negligibly small under typical reaction conditions.