Thermal degradation of l,6-anhydro-/3-D-glucopyranose-l-14C, -2-uC, and -6-uC gave carbon dioxide, carbon monoxide, and a variety of carbonyl compounds that were isolated and traced to the labeled positions. Variations of the yields and radiochemical patterns of the products on addition of sodium hydroxide or zinc chloride indicated the nature of the complex consecutive and concurrent reactions involved.

Thermal analysis and chemical studies have shown that crystalline -D-xylopyranose on melting equilibrates with the /3-d form. Heating of this mixture and a variety of /3-D-xylopyranosides at steadily increasing temperatures resulted in the cleavage of the glycosidic group, polymerization of the glycosyl moiety, and decomposition within a narrow range. When ZnCl2 was added as a catalyst, the cleavage and polymerization reactions occurred at a much lower temperature than decomposition of the polymer, and there was considerable charring.Esr spectroscopy and isothermal kinetic investigations indicate a heterolytic mechanism for the initial glycosidic cleavage.

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