# US 2019/0169317 A1 · Unsaturated Derivatives of Polysaccharides, Method of Preparation Thereof and Use Thereof

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- Number: US 2019/0169317 A1
- Document ID: US20190169317A1
- Status: Published application
- Kind: A1
- Application number: 16/311,745
- Filed: 2017-06-26
- Published: 2019-06-06
- Earliest claimed: 2016-06-27
- Assignees: Contipro A.S.
- Applicants: Contipro a.s.
- Inventors: Radovan Buffa; Tomas Bobula; Petra Sedova; Ivana Basarabova; Pavlina Prochazkova; Hana Vagnerova; Iva Doleckova; Sona Moravcikova; Vladimir Velebny
- Web page: https://patentgrep.com/patent/US20190169317A1

## CPC

- C08B 37/0072: {Hyaluronic acid, i.e. HA or hyaluronan; Derivatives thereof, e.g. crosslinked hyaluronic acid (hylan) or hyaluronates}
- A61K 31/726: Glycosaminoglycans, i.e. mucopolysaccharides (chondroitin sulfate, dermatan sulfate A61K31/737)
- A61K 31/728: Hyaluronic acid
- A61K 31/731: Carrageenans
- A61K 31/737: Sulfated polysaccharides, e.g. chondroitin sulfate, dermatan sulfate (A61K31/727 takes precedence)
- A61P 35/00: Antineoplastic agents
- A61P 39/06: Free radical scavengers or antioxidants
- C08B 37/00: Preparation of polysaccharides not provided for in groups C08B1/00 - C08B35/00; Derivatives thereof (cellulose D21; {microbiological processes C12P})
- C08B 37/0042: {Carragenan or carragen, i.e. D-galactose and 3,6-anhydro-D-galactose, both partially sulfated, e.g. from red algae Chondrus crispus or Gigantia stellata; kappa-Carragenan; iota-Carragenan; lambda-Carragenan; Derivatives thereof}
- C08B 37/0069: {Chondroitin-4-sulfate, i.e. chondroitin sulfate A; Dermatan sulfate, i.e. chondroitin sulfate B or beta-heparin; Chondroitin-6-sulfate, i.e. chondroitin sulfate C; Derivatives thereof}
- 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

## Abstract

The invention relates to the preparation of new polysaccharide derivatives comprising a double bond in the positions 4 and 5 of the pyranose cycle. The method of preparation consists in the oxidation of OH group in the position 6 to an aldehyde, followed by the elimination to form a double —C═C— bond in the positions 4 and 5, and the fmal reduction of the aldehyde group in the position 6 into the original alcohol. The derivatives of polysaccharides prepared according to the invention show an enhanced antioxidant activity and some of them also a selective negative influence on carcinoma cell viability. (formula) where R represents —NH—CO—CH3 or —OH.

## Claims

### Claim 1

Unsaturated derivatives of polysaccharides comprising, in their structure, at least one heterocycle having a double bond in positions 4 and 5 according to the structural formula X,
where R represents —NH—CO—CH3 or —OH.

### Claim 2 (depends on 1)

Unsaturated derivatives of polysaccharides according to claim 1 characterized in that their molecular weight is in the range of 5.103 to 5.105 g.mol−1 and that the polysaccharides are selected from the group consisting of chondroitin sulfate, carrageenan, dermatan sulfate, hyaluronic acid, and keratan sulfate.

### Claim 3 (depends on 1)

A method of preparation of the polysaccharide derivatives defined in claim 1 characterized in that the starting polysaccharide, comprising the fragment Y
where R is —NH—CO—CH3 or —OH, and R1 is —SO2—ONa, —SO2—OH or —H, is in the first step oxidized to an aldehyde in the position 6, in the second step the oxidized polysaccharide is eliminated in the positions 4 and 5 of the cycle to form a double bond, and in the third step the aldehyde group is selectively reduced.

### Claim 4 (depends on 3)

The method of preparation according to claim 3 characterized in that the starting polysaccharide is chondroitin sulfate, carrageenan, dermatan sulfate, hyaluronic acid, or keratan sulfate.

### Claim 5 (depends on 3)

The method of preparation according to claim 3 characterized in that, in the first step, the oxidation in the position C-6 proceeds either by means of the R3-TEMPO/NaClO system, where R3 is hydrogen or N-acetyl group, in water at the temperature of 0° C. to 10° C., wherein the molar amount of NaClO is within the range of 0.3 to 0.8 eq. and the molar amount of R3-TEMPO is within the range of 0.005 to 0.2 eq., with respect to the repeating unit of the polysaccharide, or by means of 1,1,1-triacetoxy-1,1-dihydro-1,2-benziodoxol-3(1H)-one (DMP) in DMSO at the temperature of 10° C. to 50° C., wherein the amount of DMP is within the range of 0.05 to 2 eq., with respect to the repeating unit of the polysaccharide.

### Claim 6 (depends on 3)

The method of preparation according to claim 3 characterized in that the starting polysaccharide is hyaluronic acid or keratan sulfate, and that, in the second step, the oxidized polysaccharide undergoes the elimination reaction in a mixture of water/polar aprotic solvent in the presence of a base at the temperature of 30 to 80° C.

### Claim 7 (depends on 6)

The method of preparation according to claim 6 characterized in that the amount of the base is 5 to 10 eq., with respect to the repeating polysaccharide unit, wherein the base is selected from the group consisting of pyridine, triethylamine, N,N-diisopropylethylamine, and Ca(OH)2.

### Claim 8 (depends on 6)

The method of preparation according to claim 6 characterized in that the aprotic solvent is water miscible and comprises DMSO or sulfolane, and the volume ratio of solvent/water is in the range of 3/1 to 1/2.

### Claim 9 (depends on 6)

The method of preparation according to claim 6 characterized in that the second reaction step proceeds for 12 to 150 hours.

### Claim 10 (depends on 3)

The method of preparation according to claim 3 characterized in that the starting polysaccharide is chondroitin sulfate, carrageenan, or dermatan sulfate, and that the oxidized polysaccharide is spontaneously eliminated in the second step directly in the reaction mixture to form an α,β-unsaturated aldehyde, and the spontaneous elimination proceeds without the necessity of adding any base, organic solvent, and without increasing the reaction temperature.

### Claim 11 (depends on 3)

The method of preparation according to claim 3 characterized in that the molecular weight of the starting polysaccharide is in the range of 5.103 to 5.105 g.mol−1.

### Claim 12 (depends on 3)

The method of preparation according to claim 3 characterized in that sodium borohydride is added in the third step in the amount of 0.1 to 10 equivalents, calculated with respect to the repeating polysaccharide unit, in water, at the temperature of 5-40° C., at the pH in the range of 5 to 10.

### Claim 13 (depends on 1)

Use of the derivatives as defined in claim 1 for the preparation of materials having enhanced antioxidation effect.

### Claim 14 (depends on 2)

Use of the derivatives as defined in claim 2, where the polysaccharide is hyaluronic acid, for the preparation of materials having an anti-cancer effect.

### Claim 15 (depends on 2)

Use of the derivatives as defined in claim 2 for the preparation of materials having enhanced antioxidation effect.

### Claim 16 (depends on 3)

The method of preparation according to claim 3 characterized in that the starting polysaccharide is hyaluronic acid or keratan sulfate, and that, in the second step, the oxidized polysaccharide undergoes the elimination reaction in a mixture of water/polar aprotic solvent in the presence of a base at a temperature of 50° C. to 60° C.

### Claim 17 (depends on 6)

The method of preparation according to claim 6 characterized in that the amount of the base is 0.01 to 20 eq., with respect to the repeating polysaccharide unit.

### Claim 18 (depends on 3)

The method of preparation according to claim 3 characterized in that sodium borohydride is added in the third step in the amount of 0.3 to 2 equivalents, calculated with respect to the repeating polysaccharide unit, in water, at a temperature of 15-25° C., at a pH in the range of 6 to 8.