JP2003113201A - Method for producing oxidized polyamino sugar derivative - Google Patents

Abstract

(57) [Problem] To provide a modified polyaminosugar having a function comparable to a high molecular weight mucopolysaccharide by introducing a sufficient amount of a carboxyl group into a polyaminosugar. A polyaminosugar having improved water solubility is oxidized with hypochlorous acid or a salt thereof in the presence of a nitroxyl compound.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an oxidized polyamino sugar derivative using a polyamino sugar as a raw material and a method for producing the same.

[0002]

2. Description of the Related Art In recent years, various derivatives prepared from natural polysaccharides have been widely studied and used because of their high biodegradability and biocompatibility. Among these natural polysaccharides, chitin, polyamino sugars typified by chitosan, and various derivatives using these as raw materials have acetamide group and amino group in the repeating unit, and have biocompatibility, physiological activity, or chelating property. Has attracted attention in various fields,
It is applied to pharmaceutical raw materials, cosmetic raw materials, flocculants, etc. Chitin is a compound that is present in many crustacean shells such as crabs and shrimps and in the skeletons of insects, and has a linear structure in which N-acetyl-D-glucosamine is linked by β-1,4, and is deacetylated. Results in chitosan having a free amino group. Chitin is a substance that is extremely insoluble, and is insoluble in water, dilute acid, and dilute alkali. Chitosan, on the other hand, is only soluble in acidic solutions.

[0003] Among the polysaccharides, mucopolysaccharides and glycosaminoglycans are complex polysaccharides containing amino sugars widely distributed in the connective tissue substrates and body fluids of animals, and most of them are uronic acid containing a carboxyl group. It has a linear structure consisting of repeating structures of disaccharide units. For example, hyaluronic acid, chondroitin, chondroitin sulfate, heparin and the like. These mucopolysaccharides are known to have many biological functions such as anticoagulant activity, fat serum clearing action, lubrication function, and water retention function, and they are useful substances that are still being actively studied.

These mucopolysaccharides are generally expensive, and attempts have been made to obtain cheaper analogues in consideration of application in more fields. Relatively similar structure, the method of denaturing cheaper polyamino sugar is common,
Japanese Patent Publication No. 61-501923 discloses a chitin oxide as a glycosaminoglycan polymer that can be used in the beauty field, and CrO ₃ , NO ₂ gas or its liquid dimer (N ₂ O ₄ ) as an oxidizing agent. The manufacturing method used is disclosed. Further, in JP-A-59-106409, as a chitin compound-containing cosmetic, carboxymethyl chitin and the like are disclosed.
No. 105801 discloses a novel chitosan compound, a method for producing the compound, and an application as a moisturizer, N-
Disclosed is a production method of reacting (3-carboxypropanoyl) -6-O- (carboxymethyl) chitosan and 6-O- (carboxymethyl) chitosan with succinic anhydride. Further, JP-A-2000-256404 discloses a compound obtained by oxidizing and acetylating chitosan as an oxidized chitosan compound, and chromic anhydride, sodium permanganate, hydrogen peroxide, sodium hypochlorite and the like as oxidizing agents. ing.

However, in these modification methods, because the raw materials chitin and chitosan have poor solubility, a functional group is not always introduced sufficiently and a high molecular weight modified product is not obtained. In the method using the method, the target function is sufficiently expressed due to the non-uniformity of the distribution of substituents and the low degree of substitution. Still, there is still a demand for a cheaper modified polyamino sugar as a mucopolysaccharide analog.

On the other hand, Carbohydr. Res. , 2
69, 89-98 (1995), WO95 / 07303.
Describes a selective oxidation of a water-soluble glucan and a primary alcohol of a carbohydrate, and a reaction in an aqueous solution using sodium hypochlorite as an oxidizing agent in the presence of TEMPO and sodium bromide. According to these documents and patents, oxides of primary alcohols can be obtained in high yield with high selectivity, but the obtained polysaccharide oxides cause molecular chain scission at the same time as oxidation. It is not preferable. Also, since it does not cause molecular chain breakage, bromine,
Unless bromide, iodine, or iodide is allowed to coexist, the oxidation reaction rate decreases, and in some cases, the reaction may apparently not proceed. As a method for increasing the reaction rate, methods such as increasing the reaction temperature and increasing the pH during the reaction are conceivable, but these methods are also unfavorable because they cause molecular chain cleavage. See also J. Carbohydrate Che
m. , 15, 819-830 (1996), chitin,
Although there is a description regarding the above-mentioned oxidation method using a water-insoluble polysaccharide such as chitosan as a substrate, only chitin has a low oxidation yield of about 40%, and it is described that chitosan having a high oxidation yield also has a significant decrease in viscosity. Yes, low molecular weight is suggested. Also, Cellulose, 5,153-164 (199
8) also describes the above-mentioned oxidation method using chitin, chitosan or the like as a substrate, but it seems that selective oxidation reaction of chitin is progressing, but it is generally pointed out that low molecular weight is exhibited, and chitin is remarkable. It is said that depolymerization is occurring.

[0007]

The object of the present invention is to obtain a cheaper mucopolysaccharide analogue, and in particular, it is comparable to a high molecular weight mucopolysaccharide in which a sufficient amount of a carboxyl group is introduced. To obtain a modified polyamino sugar having a function, and to provide a method for producing the same.

[0008]

Means for Solving the Problems As a result of intensive studies on the method for solving the above-mentioned problems, the inventors of the present invention have used a polyamino sugar having improved water solubility in the presence of a nitroxyl compound as a raw material to prepare hypochlorous acid. The present invention has been completed by discovering that a polyamino sugar modified product having a sufficient amount of carboxyl groups and having a high molecular weight and a function comparable to that of mucopolysaccharide can be obtained by oxidizing the salt with a salt thereof. .

The polyamino sugar used in the present invention is one in which the alcoholic hydroxyl group of the sugar in the repeating unit is substituted with an N-substituted amino group such as an amino group and an acetamide group, and its derivatives are also included. It may be a simple polysaccharide consisting only of amino sugar and its derivative, or a complex polysaccharide consisting of plural sugars containing amino sugar and its derivative. The binding style is
Α-bonded type found in starch, β found in cellulose
Any combination type may be used. As polyamino sugar and its derivative, polyglycosamine such as chitin and chitosan,
Polygalactosamine, hyaluronic acid, chondroitin,
Mucopolysaccharides such as chondroitin sulfate, and derivatives thereof, and polysaccharides produced by microorganisms having a similar structure, and polysaccharides obtained by introducing an amino group into a polysaccharide that does not originally have an amino group, such as starch and cellulose. Is also included. Chitin, chitosan and their derivatives, and polygalactosamine are preferable from the viewpoint of raw material cost and availability. From the purpose of maintaining a high molecular weight of the polysaccharide derivative after the oxidation reaction,
The above-mentioned polysaccharide is subjected to a treatment for chemically or physically lowering the molecular weight or a treatment for promoting molecular chain scission during the oxidation reaction in advance, or a polysaccharide containing impurities that promotes molecular chain scission during the oxidation reaction. Sugars are not preferred.

In the present invention, in order to promote the oxidation reaction while suppressing the molecular chain scission, a polysaccharide that has been pretreated to improve the water solubility is used as a raw material. Examples of the pretreatment method for improving the water solubility include a method of reacting ethylene oxide and propylene oxide, a method of carboxymethylation, a method of succinylation, and the like. The pretreatment method for adjusting the acetylation degree of the amino group of the polyamino sugar is used. A method using a polysaccharide having improved properties as a raw material is preferable. Most polyamino sugars are naturally N-acetylated and exist, and when treated with concentrated alkali, they are deacetylated to have a structure having a free amino group. The method for adjusting the degree of acetylation may be either deacetylation or partial acetylation of polyamino sugar having a free amino group.

Alkali agents used during deacetylation include alkali (earth) metal hydroxides such as sodium hydroxide, potassium hydroxide, lithium hydroxide, barium hydroxide and calcium hydroxide, sodium carbonate and potassium carbonate. Alkali metal carbonates such as and the like can be mentioned, and sodium hydroxide and potassium hydroxide are preferable. The concentration of the alkaline agent solution is 10% or more, preferably 40% or more. The temperature at which N-acetylpolyamino sugar is immersed in an alkaline agent solution for deacetylation should be maintained at 50 ° C or lower,
In order to suppress the molecular chain breakage or to improve the solubility, it should be maintained at preferably 30 ° C or lower, more preferably 5 ° C or lower. When the N-acetylpolyamino sugar is immersed in the alkaline agent solution, it may be dispersed more effectively in the alkaline agent solution and then kept under reduced pressure with stirring to more effectively perform the immersion. After sufficiently immersing the N-acetyl polyamino sugar in the alkaline agent solution, ice or water is added to adjust the concentration of the alkaline agent solution to 5% or more and 25% or less, and the deacetylation is advanced by further aging for 1 hour to 1 week. . afterwards,
Neutralize with an acid such as hydrochloric acid or acetic acid. During this neutralization operation,
It should preferably be maintained below 30 ° C, more preferably below 5 ° C. Although it may gelate with the neutralization operation, it is precipitated in an excessive amount of cold hydrous acetone as necessary. The gel and the precipitate are collected by a solid-liquid separation operation such as filtration and centrifugation, sufficiently washed with a water-soluble organic solvent such as hydrous acetone, methanol and ethanol, and the precipitate is dried to obtain a deacetylated product. Deacetylation degree depends on the concentration of alkaline agent,
Determined by substrate concentration, temperature, time, etc. Of course, the deacetylated product may be obtained by another method such as utilizing a deacetylase.

The partial acetylation of the polyamino sugar having a free amino group is carried out by adding acetic anhydride under ice cooling. As the polyamino sugar having a free amino group, those having a deacetylation degree close to 1.0 and being soluble in an acidic solution are desirable. First, an amino sugar having a free amino group is dissolved in an acid. Examples of the acid to be used include organic acids such as acetic acid and formic acid, and inorganic acids such as hydrochloric acid and nitric acid. Acetic acid and hydrochloric acid are preferable, and the acid concentration is preferably 1% or more and 15% or less. Then, after diluting this solution with a water-soluble organic solvent such as methanol or ethanol,
A highly swollen gel results when dropped into ice-cold pyridine. The gel is collected by a solid-liquid separation operation such as filtration and centrifugation, pulverized, washed with pyridine, and dispersed again in pyridine. The timing of adding acetic anhydride may be immediately after dissolution in acid, after dilution with a water-soluble organic solvent, or after gelation. Acetic anhydride was previously added to pyridine,
It may be gelled. The operation after adding acetic anhydride is unnecessary. After that, aging is carried out to promote acetylation, if necessary, and then precipitation is carried out in an excess amount of cold hydrous acetone, if necessary. The gel and the precipitate are collected by a solid-liquid separation operation such as filtration and centrifugation, sufficiently washed with a water-soluble organic solvent such as water-containing acetone, methanol and ethanol, and the precipitate is dried to obtain a partially acetylated product. Not only N-acetylation but also O
-If acetylation also proceeds, partial hydrolysis of the O-acetyl group is required. Agitation of an alkaline agent in an alcohol solution is effective, and sodium hydroxide and potassium hydroxide are preferred as the alkaline agent, and methanol and ethanol are preferred as the alcohol. The gel and precipitate are collected by solid-liquid separation operations such as filtration and centrifugation, and water-containing acetone,
It is sufficiently washed with a water-soluble organic solvent such as methanol and ethanol, and the precipitate is dried to obtain a partial N-acetylated product. The degree of acetylation is determined by the amount of acetic anhydride, timing of addition, substrate concentration, temperature, time and the like.

From the viewpoint of improving the water solubility and obtaining a mucopolysaccharide-like substance, the degree of acetylation is preferably 0.3 or more, more preferably 0.4 or more and 0.8 or less. The degree of acetylation was obtained by dividing the number of N-acetylamino groups in the repeating unit by the total number of N-acetylamino groups and free amino groups, calculated from the nitrogen content and carbon content by elemental analysis, and IR of 1655 cm ^{−. It} can be measured by calculation from the absorbance ratio of the amide absorption I of ^{1 and} the hydroxyl absorption of 3450 cm ⁻¹ .

The nitroxyl compound used in the oxidation step of the present invention is a hindered amine N-oxide, particularly a hindered amine N-oxide having a bulky group at the α-position of an amino group, and a di-tertiary compound. And alkyl nitroxyl compounds. 2,2,6,6-Tetraalkylpiperidine-1-oxyl, 4-hydroxy-di-tert-alkylnitroxyl compound
2,2,6,6-tetraalkylpiperidine-1-oxyl and 4-alkoxy-2,2,6,6-tetraalkylpiperidine-1-oxyl can be mentioned.
2,6,6-tetramethylpiperidine-1-oxyl,
4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl, 4-methoxy-2,2,6,6-
Tetramethylpiperidine-1-oxyl is preferred,
2,2,6,6-Tetramethylpiperidine-1-oxyl (TEMPO) is particularly preferred.

Oxidation reaction conditions for advancing the oxidation reaction while suppressing molecular chain breakage depend on the amount of the oxidizing agent used in the oxidation step.
It is preferable that the glucopyranose constituting the polyamino sugar is 0.1 to 2.0 equivalents per unit weight, the reaction temperature is -5 to 50 ° C, and the pH of the reaction system is 7 to 11, and the amount of the oxidizing agent used is 1.0. It is more preferable that the pH of the reaction system is 8 to 10 equivalents or more, and it is particularly preferable that the amount of the oxidizing agent used is 1.6 equivalents or more and the pH of the reaction system is 8-9. Use of more than 2.0 equivalents of oxidizer, heating above 50 ° C, pH
A reaction with a strong alkalinity of more than 11 causes molecular chain scission, which is not preferable. If less than 0.1 equivalent of oxidant is used, a temperature lower than -5 ° C, and a pH lower than 7, the oxidation reaction does not proceed sufficiently. Also, during oxidation, bromine, bromide,
From the viewpoint of suppressing molecular chain scission, iodine or iodide is used in an amount of less than 40 mol% per glucopyranose or glucofuranose unit constituting the polysaccharide, preferably less than 20 mol%, particularly preferably not present in the reaction system. .

The oxidized polyamino sugar derivative of the present invention is a polyamino sugar in which a primary alcohol of a polysaccharide is selectively oxidized to a carboxylic acid, and glucopyranose or gluco having a carboxyl group as a primary alcohol oxide constitutes a polyamino sugar. Containing 5 to 100 mol% per furanose unit. From the viewpoint of improving water solubility and obtaining a mucopolysaccharide-like substance,
Preferably 40 mol of carboxyl group per glucopyranose or glucofuranose constituting the polyamino sugar
% Or more, more preferably 75 mol% or more, particularly preferably 90 mol% or more. In addition, the molecular weight is an important factor for expressing a function comparable to that of mucopolysaccharide. For example, natural hyaluronic acid is said to be a high molecular weight substance having a molecular weight of 1 to 3 * 10 ⁶ . Since the molecular weight of the oxidized polyamino sugar derivative of the present invention has a distribution, when expressed by the average molecular weight,
The weight average molecular weight is 100,000 or more, preferably the weight average molecular weight is 500,000 or more, and more preferably the weight average molecular weight is 1,000,000 or more.

The oxidized polyamino sugar derivative of the present invention is a mucopolysaccharide analog and has various functions comparable to those of mucopolysaccharide, but among them, when compared with natural hyaluronic acid, which has excellent moisture absorption and retention properties, It had an equivalent function. That is, the oxidized polyamino sugar derivative of the present invention is a cheaper natural hyaluronic acid-like substance, and is suitable as a raw material for cosmetics or a raw material for pharmaceuticals.

[0018]

EXAMPLES The present invention will be described in detail below with reference to examples.
In the examples, the measurement of the acetylation degree was calculated by the IR method. Amide absorption I at 1655 cm ^-1 and 3450
It was calculated by the following formula from the correlation coefficient between the absorbance ratio of hydroxyl group absorption at cm ⁻¹ and the N-acetyl group content. In addition, O-
The ester absorption derived from the acetyl group is observed near 1750 cm ^-1 . N-acetylation degree = (A ₁₆₅₅ / A ₃₄₅₀ ) /1.33 However, A ₁₆₅₅ : ₁₆₅₅ cm ⁻¹ absorbance A ₃₄₅₀ : ₃₄₅₀ cm ⁻¹ absorbance The molecular weight is determined by size exclusion chromatography (SEC) method using pullulan as a standard substance. It measured on the conditions shown below and calculated the pullulan conversion weight average molecular weight. still,
The calibration curve was prepared using pullulan with a molecular weight of up to 1.6 * 10 ^{6 and} was within the exclusion limit range of the separation column.
I did so until 0 * 10 ⁷ . Separation column: Shodex OHpak SB-806MHQ + SB-802.5HQ Column temperature: 40 ° C Eluent: 0.10M NaCl + 0.06M Na ₂ HPO ₄ + 0.04M KH ₂ PO ₄ Flow rate: 0.8ml / min Injection rate: Approx.1.0W / V% 10 μl Detector: RI The production ratio of carboxyl groups in the oxidized polyamino sugar derivative was measured by the NMR method. After dissolving the sample in heavy water, by ¹³ C-NMR, a peak derived from the methylene carbon of the primary alcohol detected near the chemical shift of 60 ppm and a peak derived from the quaternary carbon of the carboxyl group detected near the same 180 ppm. The peak area ratio of was calculated by comparison. In addition, the moisture absorption and retention characteristics are 2
It is left in a desiccator with a relative humidity of 81% in a saturated aqueous solution of ammonium sulfate at a constant temperature of 5 ° C, the weight change with time is measured, the moisture absorption rate is calculated by the following formula, and the moisture absorption characteristics are evaluated. The amount of water was added, and the mixture was allowed to stand in a silica gel desiccator at a constant temperature of 25 ° C., the weight change with the passage of time was measured, and the residual moisture ratio was calculated by the following formula to evaluate the moisturizing property. Moisture absorption rate (%) = (WS) / S * 100 Moisture residual rate (%) = (WS) / H * 100 where S: dry sample weight (g) W: sample weight after standing (g) H: Weight of added water (g)

Example 1 2.50 g of powdered chitin (reagent) was added to a 200 ml eggplant flask containing 50 ml of 48% NaOH aqueous solution under ice-cooling, while stirring with a rotary evaporator to give 20
The pressure was reduced to mmHg, and stirring was continued while ice-cooling for 45 minutes. The chitin solution became a uniform viscous fluid.
After returning to normal pressure, 108 g of crushed ice was added thereto, and the mixture was stirred at room temperature for 5 minutes.
The mixture was thoroughly agitated for a time to promote deacetylation. Further, this was placed in a beaker, and while monitoring with a pH meter, concentrated hydrochloric acid and dilute hydrochloric acid were sequentially added under ice cooling to neutralize and the pH was adjusted to 9.
The viscosity increased during the neutralization operation. 1 l of ice-cold acetone was placed in a beaker, and the neutralized solution was added dropwise with sufficient stirring to give a white precipitate. After filtering the precipitate by suction filtration,
After thoroughly washing with acetone / water = 4/1 (volume ratio), it was collected, dried under vacuum at 50 ° C. overnight, and deacetylated chitin 2.
25 g was obtained. The acetylation degree by IR method was 0.70. 3 equipped with stirrer, thermometer, pH meter, ORP meter, sodium hypochlorite and sodium hydroxide supply pipes
2.25 g of the above deacetylated chitin and 200 ml of water were added to a 00 ml round bottom separable flask and suspended by stirring. Add 100 mg of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) and add 1
3.5% sodium hypochlorite 11.04 g (20 mm
ol) was added dropwise over 175 minutes while paying attention to the increase in pH at the initial stage of the reaction and the sudden increase in ORP. During this period, a 2N-sodium hydroxide solution was added dropwise and the pH was sufficiently stirred.
= 9.0 and the reaction solution temperature = 20 ° C, the reaction was continued. Since a pH increase was observed at the initial stage of the reaction, a total of 9 ml of 1N-hydrochloric acid solution was added. After 220 minutes, the consumption of sodium hydroxide due to the decrease in pH stopped and the reaction was stopped.
A small amount of solid matter remained in the reaction solution. The consumption amount of sodium hydroxide was 6.1 mmol. The reaction solution was added dropwise to twice the volume of acetone to carry out a precipitation operation. After filtering off the precipitate by suction filtration, acetone / water = 4
It was sufficiently washed with 1/1 (volume ratio), collected, and vacuum dried at 50 ° C. overnight to obtain 2.49 g of oxidative deacetylated chitin. As a result of SEC analysis, some insoluble matter was found, but the pullulan-equivalent weight average molecular weight of the soluble matter was 100,000. In addition, when ¹³ C-NMR spectrum of the soluble matter was measured after dissolution by heating in heavy water, no peak derived from methylene adjacent to the unreacted primary alcohol was detected, and 6-position carboxyl group carbon and N-acetyl 180p peak derived from the group
Two were observed near pm and six other main peaks were observed. Therefore, it was confirmed that the main product was a repeating N-acetylglucosamine structure in which the primary alcohol at the 6-position was selectively oxidized to generate a carboxyl group.

Example 2 2.50 g of powdered chitin (CHA-1, Katakura Tickerin)
Is treated in the same manner as in Example 1 to deacetylate chitin 2.2.
9 g was obtained. The degree of acetylation by IR method was 0.72. Although the immersion time under reduced pressure was set to 160 minutes, particles were recognized and a uniform fluid was not obtained. Oxidation was carried out in the same manner as in Example 1 to obtain 2.50 g of oxidative deacetylated chitin. In addition, TEMPO amount is 50 mg, 13.5% sodium hypochlorite is 11.60 g (21 mmol) 220
The solution was added dropwise over a period of minutes, the reaction was carried out for 330 minutes, and 5.2 mmol of sodium hydroxide was consumed. As a result of SEC analysis, some insolubles were found, but the pullulan-equivalent weight average molecular weight of the solubles was 700,000. When the ¹³ C-NMR spectrum of the soluble matter was measured after heating by heating in heavy water, the same main peak as in Example 1 and a slight sub-peak were observed.

Example 3 2.00 g of powdered chitosan (reagent) was added to 10% acetic acid solution 1
It was added to a 500 ml separable flask containing 50 ml, and stirred and dissolved. 150 ml of methanol in this solution
Was added and the mixture was stirred again to give a viscous solution. 600 ml of ice-cooled pyridine was placed in a beaker, and this solution was added dropwise with sufficient stirring to cause gelation. The gel was pulverized with a homogenizer under ice cooling and further washed with pyridine. Transfer the gel to a separable flask and add pyridine 100
Add ml and stir with ice cooling to remove acetic anhydride.
6 g (124 mmol) was added dropwise, and stirring was continued at room temperature for 18 hours. Place 700 ml of ice-cold acetone in a beaker,
When the gel was added dropwise with pyridine with sufficient stirring, a white precipitate formed. The precipitate was collected by suction filtration, washed thoroughly with acetone, collected, and vacuum dried at 50 ° C. overnight. When IR measurement of this solid was performed, ester absorption derived from O-acetyl group was observed at around 1750 cm ⁻¹ , so 0.56 g (10 mmol) of potassium hydroxide was dissolved in 100 ml of methanol, and this solid was Was added and stirred at room temperature for 6 hours for ester hydrolysis. The precipitate was collected by suction filtration, washed thoroughly with methanol, collected, and vacuum dried at 50 ° C. overnight to obtain 1.65 g of partially acetylated chitosan. The acetylation degree by IR method was 0.75. Oxidation was carried out in the same manner as in Example 1 to obtain 1.77 g of oxidized partially acetylated chitosan. In addition, TE
MPO amount is 50 mg, and 13.5% sodium hypochlorite 8.50 g (15.4 mmol) is added dropwise over 130 minutes and reacted for 180 minutes to obtain sodium hydroxide 3.8.
mmol consumed. As a result of SEC analysis, some insoluble matter was found, but the pullulan-equivalent weight average molecular weight of the soluble matter was 500,000. In addition, it was heated in heavy water to dissolve the soluble content of ¹³
When the C-NMR spectrum was measured, the same main peak as in Example 1 was observed.

Example 4 Deacetylated chitin obtained by the same treatment as in Example 2 was oxidized by the same apparatus as in Example 1 to obtain 2.49 g of oxidized deacetylated chitin. Incidentally, sodium bromide 16
0 mg (1.56 mmol) coexisted, the amount of TEMPO was 50 mg, and 13.5% sodium hypochlorite was 11.
60 g (21 mmol) was added dropwise over 120 minutes, and 1
After reacting for 70 minutes, 6.4 mmol of sodium hydroxide was consumed. As a result of SEC analysis, some insoluble matter was found, but the pullulan-equivalent weight average molecular weight of the soluble matter was 500,000. In addition, ¹³ C-NM which is soluble after being heated in heavy water and dissolved
When the R spectrum was measured, a main peak similar to that in Example 1 and a slight sub-peak were observed.

Example 5 The moisture absorption and retention properties of the oxides obtained in Examples 1 to 4 were evaluated together with the microorganism-produced sodium hyaluronate (pure chemical reagent). Tables 1 and 2 show changes with time of the moisture absorption rate and the moisture remaining rate. From these results, the moisture absorption / retention characteristics of the oxides obtained in Examples 1 to 4 were similar to those of sodium hyaluronate.

[0024]

[Table 1]

[0025]

[Table 2]

Comparative Example 1 300 ml equipped with a stirrer, thermometer, pH meter, ORP meter, sodium hypochlorite and sodium hydroxide supply pipes
Powder chitin (reagent) in a round bottom separable flask 2.
50 g and 200 ml of water were added and suspended by stirring.
100 mg of TEMPO was added, and 13.
5% sodium hypochlorite 11.04 g (20 mmo
l) was added dropwise and an oxidation reaction was tried, but the oxidation reaction did not proceed and O
RP has risen. While adjusting the pH by adding a 1N-hydrochloric acid solution, a predetermined amount of 50% sodium hypochlorite was added to 170
The solution was added dropwise over minutes, but sodium hydroxide was not consumed. After standing as it was overnight, the same treatment as in Example 1 yielded 2.03 g of a solid matter, which was insoluble in water.

Comparative Example 2 An oxidation reaction was tried in the same manner as in Comparative Example 1. It should be noted that 515 mg (5.0 mmol) of sodium bromide was allowed to coexist and pH = 1.
It was set to 0.8. Sodium hypochlorite was added dropwise over 130 minutes, reacted for 170 minutes, and sodium hydroxide was added to 8.
Consumption of 4 mmol gave 2.21 g of a solid. As a result of SEC analysis, insoluble matter was also recognized, but the pullulan-equivalent weight average molecular weight of the soluble matter was 45,000. When the ¹³ C-NMR spectrum of the soluble matter was measured after heating by heating in heavy water, the same main peak as in Example 1 was observed.

Comparative Example 3 300 ml equipped with a stirrer, thermometer, pH meter, ORP meter, sodium hypochlorite and sodium hydroxide supply pipes
In a round bottom separable flask, 210m of 10% acetic acid solution
1 was added, 2.10 g of powdered chitosan (reagent) was added, and the mixture was stirred and dissolved. Add TEMPO 100mg, 2N-N
A film-like gel was deposited in an attempt to adjust pH = 9 by adding aOH, but as in Example 1, 13.5% sodium hypochlorite 15.84 g (29 mmol) was added dropwise over 260 minutes, After reacting for 270 minutes, 7.4 mmol of sodium hydroxide was consumed (excluding the neutralized portion). As a result of SEC analysis, insoluble matter was also recognized, but the pullulan-equivalent weight average molecular weight of the soluble matter was 2,000, and the ¹³ C-NMR spectrum of the soluble matter after dissolution was measured by heating in heavy water. , 63pp
A peak derived from methylene adjacent to the primary alcohol was observed near m, a peak derived from a carboxyl group was not detected, and the oxidation reaction did not proceed.

[0029]

INDUSTRIAL APPLICABILITY According to the present invention, a polyamino sugar having a sufficient amount of a carboxyl group introduced thereinto to obtain a high molecular weight mucopolysaccharide-like substance, the function of which is comparable to that of natural mucopolysaccharide. These are cheaper various natural mucopolysaccharide analogs, and as raw materials thereof, especially as cheaper natural hyaluronic acid analogs, they can be suitably used as cosmetic raw materials, pharmaceutical raw materials, etc. by utilizing their moisture absorption and retention properties. .

Claims (9)

[Claims] 1. A process for producing an oxidized polyamino sugar derivative, which comprises oxidizing a polyamino sugar pretreated to improve water solubility in the presence of a nitroxyl compound with hypochlorous acid or a salt thereof. 2. The method for producing an oxidized polyamino sugar derivative according to claim 1, wherein the nitroxyl compound is a di-tertiary alkyl nitroxyl compound. 3. The method for producing an oxidized polyamino sugar derivative according to claim 1, wherein the polyamino sugar has improved water solubility by pretreatment for adjusting the acetylation degree of the amino group of the polyamino sugar. 4. The degree of acetylation of polyamino sugar is 0.3.
The above is the method for producing an oxidized polyamino sugar derivative according to claim 3. 5. The method for producing an oxidized polyamino sugar derivative according to claim 1, wherein the polyamino sugar is chitin, chitosan and their derivatives, or polygalactosamine. 6. The method for producing an oxidized polyamino sugar derivative according to claim 1, wherein the pH of the reaction solution at the time of oxidation is set to 7 to 11. 7. The oxidized polyamino sugar derivative according to claim 1, wherein bromine, bromide, iodine or iodide is used at the time of oxidation in an amount of less than 40 mol% per glucopyranose or glucofuranose unit constituting the polyamino sugar. Production method. 8. The method for producing an oxidized polyamino sugar derivative according to claim 1, wherein bromine, bromide, iodine or iodide is not present during the oxidation. 9. A primary alcohol of 40 in the repeating unit.
% Of carboxylic acid is 100,000
Oxides of the above polyamino sugars.