Thiolation of starch and other polysaccharides

Thiolated starches with a degree of substitution of 0.01–0.6 were obtained by pyrolysis of starch dithiobis(thioformates) followed by saponification. The pyrolytic decomposition of dithiobis(thioformates) followed two pathways: (1) to thionocarbonate , carbon disulfide, and sulfur, and (2) to dithiocarbonate , carbonyl sulfide, and sulfur. Only the second pathway affords thiolation. Thiol groups were determined by Ellman's reagent, by sulfur analyses, and, following acetylation, by the ratio of O‐acetyl versus S‐acetyl absorption in nuclear magnetic resonance spectra. The poly‐saccharides cellulose, dextran, and xylan were thiolated by the same procedure.