# US 10,870,711 B2 · Process for the preparation of polysaccharides > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,870,711 B2 - Document ID: US10870711B2 - Status: Granted - Kind: B2 - Application number: 15/570,227 - Filed: 2016-05-18 - Published: 2018-05-17 - Granted: 2020-12-22 - Earliest claimed: 2015-05-20 - Assignees: Chemi S.p.A. - Applicants: Chemi S.P.A. - Inventors: Lorenzo De Ferra; Ettore Ammirati; Simona Andreassi; Mauro Annibaldi; Luca Mandelli; Barbara Pinto; Felice Stracqualursi - Web page: https://patentgrep.com/patent/US10870711B2 ## CPC - C08B 37/0057: {beta-D-Xylans, i.e. xylosaccharide, e.g. arabinoxylan, arabinofuronan, pentosans; (beta-1,3)(beta-1,4)-D-Xylans, e.g. rhodymenans; Hemicellulose; Derivatives thereof} - A61K 31/737: Sulfated polysaccharides, e.g. chondroitin sulfate, dermatan sulfate (A61K31/727 takes precedence) - A61P 37/00: Drugs for immunological or allergic disorders - C07H 11/00: Compounds containing saccharide radicals esterified by inorganic acids; Metal salts thereof (halo-sugars C07H5/02; thio-, seleno-, or telluro-sugars C07H5/08) - C08B 37/0003: {General processes for their isolation or fractionation, e.g. purification or extraction from biomass} - C08B: POLYSACCHARIDES; DERIVATIVES THEREOF (polysaccharides containing less than six saccharide radicals attached to each other by glycosidic linkages C07H; fermentation or enzyme-using processes C12P19/00; sugar industry C13; production of cellulose D21) - A61K: PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES (devices or methods specially adapted for bringing pharmaceutical products into particular physical or administering forms A61J3/00; chemical aspects of, or use of materials for deodorisation of air, for disinfection or sterilisation, or for bandages, dressings, absorbent pads or surgical articles A61L; soap compositions C11D) - A61P: SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS - C07H: SUGARS; DERIVATIVES THEREOF; NUCLEOSIDES; NUCLEOTIDES; NUCLEIC ACIDS (derivatives of aldonic or saccharic acids C07C, C07D; aldonic acids, saccharic acids C07C59/105, C07C59/285; cyanohydrins C07C255/16; glycals C07D; compounds of unknown constitution C07G; polysaccharides, derivatives thereof C08B; DNA or RNA concerning genetic engineering, vectors, e.g. plasmids, or their isolation, preparation or purification C12N15/00; sugar industry C13) ## Abstract The present invention relates to a process for the preparation of a polysaccharide composed of D-xylose units of formula (III) linked together via beta 1,4 glycosidic bonds wherein R1 is hydrogen or acetyl, R2 is hydrogen, acetyl or a 4-O-methyl glucuronic acid unit, wherein, when R2 is a 4-O-methyl glucuronic acid unit, the R1 group on the same saccharide unit is defined as G, wherein G is hydrogen or acetyl, and wherein the sugar unit at the reducing end of sun such polysaccharide is xylose, lyxose or xylulose, said process comprising the following steps: selective deacetylation of xylan extracted from beech wood; and isomerization of the selectively deacetylated xylan achieved in step or the following steps: isomerization of xylan extracted from beech wood; and selective deacetylation of isomerized xylan achieved in step. The process is useful for the preparation of pentosan polysulfate or pharmaceutically acceptable salts thereof for pharmaceutical use. ## Claims ### Claim 1 Process for the preparation of a polysaccharide composed of D-xylose units of formula (III) linked together via beta 1,4 glycosidic bonds wherein R1 is hydrogen or acetyl, R2 is hydrogen, acetyl or a 4-O-methyl glucuronic acid unit, wherein, when R2 is a 4-O-methyl glucuronic acid unit, the R1 group on the same saccharide unit is defined as G, wherein G is hydrogen or acetyl, and wherein the sugar unit at the reducing end of the polysaccharide is, lyxose or xylulose, said process comprising the following steps: a) selectively deacetylating xylan extracted from beech wood; and b) isomerizing the selectively deacetylated xylan achieved in step a) or the following steps: c) isomerizing xylan extracted from beech wood; and d) selectively deacetylating isomerized xylan achieved in step c). ### Claim 2 (depends on 1) The process according to claim 1 wherein step a) or step d) is performed in the presence of a basic reagent. ### Claim 3 (depends on 2) The process according to claim 2 wherein step a) or step d) is performed in aqueous environment at a pH comprised in the range between pH=8 and pH=12. ### Claim 4 (depends on 1) The process according to claim 1 wherein-step b) is performed by heating deacetylated xylan achieved in step a) in presence of pyridine. ### Claim 5 (depends on 1) The process according to claim 1 wherein step c) is performed by heating xylan extracted from beech wood in presence of pyridine. ### Claim 6 (depends on 4) The process according to claim 4 wherein that step b) or step c) is performed in the presence of at least one additional substance selected from alumina, aluminum acetate, calcium chloride and calcium acetate. ### Claim 7 (depends on 1) The process according to claim 1 wherein step a) and step b) are performed in “one-pot”. ### Claim 8 (depends on 7) The process according to claim 7 wherein the “one-pot” reaction is performed in the presence of a basic reagent and of at least one substance containing polyvalent metals in aqueous environment. ### Claim 9 (depends on 8) The process according to claim 8 wherein said at least one substance containing polyvalent metals is selected from the group consisting of-calcium chloride, calcium acetate and aluminum acetate. ### Claim 10 (depends on 1) The process according to claim 1 further comprising the step of converting the polysaccharide into pentosan polysulfate by sulfation reaction. ### Claim 11 (depends on 10) The process according to claim 10 further comprising the step of converting pentosan polysulfate into a pharmaceutically acceptable salt. ### Claim 12 (depends on 1) Process according to claim 1, wherein the polysaccharide has the formula (II) wherein R is hydrogen or acetyl, G is hydrogen or acetyl, A is a, lyxose or xylulose unit. ### Claim 13 A polysaccharide composed of D-xylose units of formula (III) linked together via beta 1,4 glycosidic bonds wherein R1 is hydrogen or acetyl, R2 is hydrogen, acetyl or a 4-O-methyl glucuronic acid unit, wherein, when R2 is a 4-O-methyl glucuronic acid unit, the R1 group on the same saccharide unit is defined as G, wherein G is hydrogen or acetyl, and wherein the sugar unit at the reducing end of such polysaccharide is, lyxose or xylulose. ### Claim 14 A polysaccharide of formula (II) wherein R is hydrogen or acetyl, G is hydrogen or acetyl, A is a, lyxose or xylulose unit.