JPH0643441B2 - Polysaccharide derivative - Google Patents

Description

The present invention relates to a novel polysaccharide derivative, and more particularly to a polysaccharide ester of a carboxylic acid having a carboxyl group directly linked to a thiophene ring or a condensed ring thereof.

Conventionally, various compounds of carboxylic acid esters of polysaccharides are known, but only a very limited number of carboxylic acid esters are known when the carboxylic acid has a carboxyl group directly linked to a thiophene ring. That is, an example of synthesis for the purpose of modifying cellulose fibers has been reported [S. Singh et al.
bohydr.Res., 17 353-363 (1971)], but the product has a degree of substitution per glucose unit of 1.0 or less,
It does not dissolve in common solvents. However, the present inventors have found that a highly substituted ester in which 50% or more of the hydroxyl groups in the polysaccharide molecule are substituted with a carboxyl group directly linked to a thiophene ring or a condensed ring thereof is soluble in an organic solvent, is an adsorbent, and is an oxygen carrier. It was found that they are useful substances that can be used as a carrier for chromatography, an optical isomer separating agent, a liquid crystal substance and the like.

That is, in the present invention, 50% or more of the hydroxyl groups in the polysaccharide molecule are represented by the following formula (Wherein R represents a thiophene ring or an aromatic condensed ring containing a thiophene ring) and is related to a polysaccharide derivative which is substituted with a group and is soluble in an organic solvent. It is an excellent one.

As the polysaccharide, those having various monosaccharides as structural units can be targeted, but those having a linear molecular structure, or those having a relatively small branching degree even if they have a branch are useful. is there. Further, it is particularly useful that the type of monosaccharide which is a constitutional unit, and the binding form thereof is about 2 or less at most, and that the structure is relatively simple. Examples of them include β-1,4-glucan containing cellulose, amylose, α-1,4-glucan containing pullulan, α containing dextran.
-1,6-glucan, curdlan, pachyman, β-1,3-glucan containing lentinan, β-2,1-fructan containing inulin, β-2,6-fructan containing levan, galactan containing agar, Polyunaloids containing alginic acid, chitin, glucosaminonan containing chitosan, and mannan,
Xylan and glucomannan, galactomannan,
Examples include heteroglycans containing arabinogalactan.

As a reaction reagent for esterifying the above-mentioned polysaccharide and leading to the derivative of the present invention, a corresponding carboxylic acid anhydride or carboxylic acid halide may be used. For example, thiophene-2-
Carbonyl chloride, thiophene-3-carbonyl chloride and the like. As the reaction catalyst, sulfuric acid, Bronsted acid such as perchloric acid, Lewis acid such as zinc chloride, and bases such as pyridine, triethylamine and 4-dimethylaminopyridine can be appropriately used.

In the synthesis of the polysaccharide derivative of the present invention, the raw material polysaccharide is once dissolved in a solvent such as water or formic acid and then precipitated in another solvent and dried, an aqueous solution is directly freeze-dried, or acetic acid. When a material obtained by hydrolyzing a polysaccharide ester such as an ester is used as a raw material, it has a large activity for the reaction and can be advantageously used.

The reactivity varies depending on the type of polysaccharide and the degree of polymerization, but the degree of substitution of the derivative can be adjusted by selecting the reaction conditions.

The polysaccharide derivative of the present invention can be used in various forms. For example, it is used after being formed into a film shape, a fiber shape, a particle shape, or the like. In this case, the degree of polymerization is relatively high, for example 60
The above is preferable in terms of physical strength of the molded product. Further, in the case of being used by being supported on fine silica gel, those having a relatively low degree of polymerization, for example, those having a degree of polymerization of about 10 to 80 are more advantageous in terms of coating properties and the like.

The present invention is described below with reference to examples, but the present invention is not limited thereto.

Example 1 Cellulose acetate was saponified with hydrazine, washed with acetone and dried to obtain cellulose. 1.5 g of the above cellulose
70 ml of dehydrated pyridine and dehydrated triethylamine
7.7 ml and 4-dimethylaminopyridine 50 mg were added, and thiophene 2-carbonyl chloride 12.2 g was added with stirring, and the mixture was reacted at 100 ° C. for 5 hours with stirring. After cooling, add the product to 400 ml of ethanol with stirring to precipitate,
After passing through a glass filter, it was thoroughly washed with ethanol.
After vacuum drying, it was dissolved in 30 ml of methylene chloride, the insoluble material was removed, and the precipitate was reprecipitated in 400 ml of ethanol. After passing through the precipitate, it was washed with ethanol, drained and dried. The sugar yield of the product was 3.9 g. The product was dissolved in methylene chloride, applied to a sodium chloride cell, dried and subjected to infrared absorption spectrum analysis. The obtained infrared absorption spectrum is as shown in FIG. 1, and the characteristic absorption bands are as follows.

3100cm ^-1 Aromatic C-H stretching vibration 1720cm ^-1 Carboxyl ester C = O stretching vibration 1360,1420,1520cm ^-1 Thiophene ring stretching vibration 1260cm ^-1 Ester C-O stretching vibration 1060 to 1160cm ^-1 Cellulose Stretching vibration of C-O-C 860 cm ^-1 2 C-H out-of-plane bending angle of 2-substituted thiophene Absorption around 3450 cm ^-1 based on OH of cellulose was hardly observed, indicating that the compound is almost a tri-substituted product. The characteristic absorptions of the proton NMR spectrum measured in CDCl ₃ are as follows.

6.8 to 7.8 ppm Thiophene ring proton 2.8 to 5.4 ppm Cellulose ring and methylene proton at the 6-position The ratio of thiophene ring proton to cellulose proton is approximately 9: 7, which is in agreement with the tri-substituted product.

In addition, elemental analysis of sulfur revealed that the sulfur content was 19.40.
Taken together, it is estimated that the product is a cellulose thiophene 2-carboxylate with a degree of substitution of about 3.0.

Example 2 Endodon of ivory palm seeds is described in the literature [GO Aspinall, eta.
1; J. Chem. Soc., 3184 (1953)] to obtain a high molecular weight fraction of mannan B. The same procedure as in Example 1 was repeated except that this mannan B powder was used instead of cellulose. As a result, 2 g of a reaction product was obtained. The product was dissolved in methylene chloride, applied to a sodium chloride cell, dried and subjected to infrared spectrum measurement. The obtained infrared absorption spectrum is as shown in FIG. 2, and the characteristic absorption bands are as follows.

3100cm ^-1 Method group C-H stretching vibration 1730cm ^-1 Carboxylic ester C = O stretching vibration 1360,1420,1530cm ^-1 Thiophene ring ring stretching vibration 1260cm ^-1 Ester C-O stretching vibration 1060-1180cm ^-1 Mannan Stretching vibration of C-O-C of 860 cm ^-1 2 C-H out-of-plane bending angle of 2-substituted thiophene Absorption around 3450 cm ^-1 based on OH of mannan is hardly recognized, and it is found that the compound is almost trisubstituted. Also
The characteristic absorptions of proton NMR measured in CDCl ₃ are as follows.

6.8 to 8.2 ppm Proton of thiophene ring 3.0 to 5.8 ppm Proton of mannan ring and methylene at the 6-position The ratio of thiophene ring proton to proton of mannan is approximately 9: 7, which is in agreement with the tri-substituted product. As a result, the product is estimated to be mannan 2-thiophenecarboxylate having a degree of substitution of 3.0 per mannose.

[Brief description of drawings]

1 and 2 are infrared absorption spectra of the polysaccharide derivatives of Examples 1 and 2, respectively.

Claims (2)

[Claims] 1. 50% or more of hydroxyl groups in a polysaccharide molecule are represented by the following formula: (In the formula, R represents a thiophene ring or an aromatic condensed ring containing a thiophene ring) and a polysaccharide derivative which is substituted with a group and is soluble in an organic solvent. 2. Polysaccharides include β-1,4-glucan containing cellulose, amylose, α-1,4-glucan containing pullulan, α-1,6-glucan containing dextran, curdlan, pakiman and lentinan. Β-1,3-glucan containing, β-2,1-fructan containing inulin, β-2,6-fructan containing levan, galactan containing agar, polyunaloid containing alginic acid, glucosaminonan containing chitin and chitosan, and mannan. The polysaccharide derivative according to claim 1, which is selected from the group of compounds consisting of heteroglycans including xylan, glucomannan, galactomannan, and arabinogalactan.