Malins and co-workers have reported the use of Py•SO3 and DMF•SO3 complexes for the preparation of sulfated xylooligosaccharides that could be a promising therapeutic agent similar to the known exemplar, pentosan polysulfate (PPS). Pentosan polysulfate is a semi-synthetic polysulfated xylan that is related to glycosaminoglycans (GAGs) containing β-1→4-linked xylooligosaccharides and was approved for the treatment of interstitial cystitis (inflammation of bladder) (Figure ). Figure . The structure of pentosan polysulfate sodium (Elmiron®) which was approved for the treatment of interstitial cystitis. 1 An initial attempt for the sulfation of xylooligosaccharides was examined on different substrates such as xylose, methyl-β-xyloside, and xylobiose using Py•SO3 complex at high temperature (60 °C) and 18 h reaction duration. Unfortunately, the β-1→4 linkage of xylan derivatives was cleaved by the addition of pyridine as pyridinium contamination (Scheme 13). Scheme 13. The sulfation reaction of xylan derivatives using Py•SO3 complex.