JPH075642B2 - Method for producing chitin derivative - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel method for producing a chitin derivative, and more particularly to a method capable of safely producing a chitin derivative in a good yield without requiring complicated steps.

[0002]

2. Description of the Related Art Chitin is a polysaccharide contained in the shells of crabs and shrimps, the shells of beetles, the cell walls of microorganisms such as molds, and the soft shells of squid. It is attracting attention as the second largest biomass.

Regarding the use and application of chitin, various researches and developments have been conventionally performed using chitin derived from crab / shrimp shell as a raw material. Among them, surgical sutures that pay attention to biocompatibility of chitin, use as artificial skin, etc., use of chitin deacetylated chitosan as food preservative that pays attention to antibacterial properties, and living body of beaded chitosan Several uses have been found and put to practical use, such as use as a catalyst-immobilized carrier and chromatography-packing material.

[0004]

[Problems to be Solved by the Invention]
Since the shrimp-derived chitin has properties such as low affinity for a solvent, being hard and rigid, it is difficult to develop a wider range of applications. In fact, most of the crab shrimp shell chitin currently produced is converted to chitosan,
Utilizing its cohesiveness, it is only used as a coagulant for excess sludge generated in the wastewater treatment process.

Although attempts have been made to prepare various derivatives by chemically modifying chitin and to use them as chitin compounds having high functionality, chitin derived from crab / shrimp shells is a fluorinated solvent. It was only dissolved in some special solvents such as, and it was difficult to chemically modify under mild conditions.

Therefore, the fact that alkaline chitin obtained by mixing chitin with a large amount of an alkali salt such as sodium hydroxide is water-soluble is used as a starting material,
Efforts have been made to produce some chitin derivatives such as partially deacetylated chitin, glycol chitin, carboxymethyl chitin, diethylaminoethyl chitin. Examples of preparation of such chitin derivatives are described, for example, in Sann.
an, T., K. Kurita, Y. Iwakura, Makromol. Chem.,
176, 1191 (1975) for the preparation of alkaline chitin, Ryoichi Sente, Satoshi Oki, Journal of the Japanese Society of Agricultural Chemistry, 23, 432 (1950) for the preparation of glyco-rutin, Satoshi Oki, The Journal of the Japanese Society of Agricultural Chemistry,
32, 303 (1958) and Trujillo, R., Carbohydr. R
es., 7, 483 (1968) for the preparation of carboxymethyl chitin, as well as K. Kurita, Y. Koyama, S. Inoue, S. N.
The preparation of diethylaminoethylchitin is disclosed in ishimura, Macromolecules, 23, 2865 (1990), respectively.

However, this method requires a single pass through alkaline chitin, which complicates the process. It is also known that the use of a reagent at a very high concentration inevitably causes a large degree of deacetylation as a side reaction, and further that the chitin main chain is cleaved to reduce the molecular weight.

In order to carry out chemical modification in a wider range, it is necessary to dissolve it in an organic solvent such as pyridine which is widely used as a solvent. However, as described above, the crab / shrimp shell chitin itself does not dissolve in an organic solvent such as pyridine, so that it has to be reacted in a state of being suspended in the organic solvent. Therefore, the reaction must be carried out under harsh conditions, it is difficult to increase the reaction rate, and the yield is extremely reduced due to the decomposition of the chitin main chain, and the product is colored. There was a problem.

[0009]

DISCLOSURE OF THE INVENTION The present inventors have found that chitin is rarely used in spite of the attention being paid to it because the method for producing a chitin derivative is a complicated and inefficient method like the above-mentioned conventional method. From the standpoint that it is unknown, we have conducted intensive studies on a simpler and more efficient method for producing a chitin derivative. As a result, crab shrimp shell chitin is very hard and rigid and insoluble in most solvents, whereas chitin derived from squid soft shell is supple and highly swellable in many solvents including pyridine. Focusing attention, it was found that a chitin derivative can be obtained very easily and efficiently by reacting with a substituent-introducing agent under this swelling condition, and the present invention has been completed.

That is, the method for producing a chitin derivative of the present invention is characterized in that squid soft shells are decalcified and deproteinized, then swollen with a solvent, and then a substituent-introducing agent is added and reacted. To do.

As the squid soft shell used in the present invention, soft shells of squid belonging to the order Tsquid such as squid, squid, squid, tsumeika, dosuika, firefly squid, and squid can be preferably used.
The type of squid is not particularly limited.

The soft shell obtained from these squid contains ash, protein and the like in addition to chitin. In the method of the present invention, first, the squid soft shell is decalcified and deproteinized to purify the squid soft shell chitin.
The decalcification treatment of the squid soft shell can be performed, for example, by immersing it in an acid of 0.05 to 2 N and leaving it for 10 minutes to 5 hours.

Further, the deproteinization treatment is carried out by, for example, 0.1
It can be carried out by immersing in an alkali solution of 3 to 3 N and allowing it to stand at room temperature for 2 to 24 hours, or by boiling it for 30 minutes to 5 hours. The order of performing the decalcification treatment and the deproteinization treatment is not particularly limited, and the decalcification treatment can be performed after the deproteinization treatment.

[0014] Typically, decalcification treatment and deproteinization treatment of squid soft shell are performed as follows. That is, first, the washed squid soft shell is roughly crushed and immersed in hydrochloric acid of about 0.1 N at room temperature for several hours. Then, boil in about 1N sodium hydroxide for about 1 hour, wash the alkaline solution with running water, and dry.

The squid soft shell does not contain pigments such as astaxanthin at all as compared with the crab / shrimp shell and has a low ash content such as calcium.
It has the property that the acid / alkali solution penetrates well. Therefore, squid soft-shell chitin can be obtained with higher purity in a reduced purification process than crab-shrimp shell chitin.

The refined squid soft shell chitin is crushed by a crusher as necessary to obtain white cotton-like fine chitin, which is then added to an appropriate solvent and dispersed to swell. The solvent used here is not particularly limited, and any solvent can be used as long as it is a solvent usually used for chemical modification of a compound. Preferred solvents include pyridine, dimethyl sulfoxide, n-methylpyrrolidone, m-crezo-
And dimethylacetamide, dimethylformamide, hexamethylphosphoramide, methanol, ethanol and dichloroacetic acid, which may be used alone or in combination of two or more.

As described above, the squid soft-shell chitin is swollen in the solvent, and a substituent-introducing agent is further added to react. Here, the substituent-introducing agent means a compound capable of substituting the 6-position hydroxyl group of chitin and, in some cases, the 3-position hydroxyl group, and various compounds are used depending on the kind of the substituent to be introduced. You can Representative examples of the substituent-introducing agent include ethylene chlorohydrin, propylene chlorohydrin, trimethylene chlorohydrin, 3-chloro-1,2-propanediol, ethylene oxide, propylene oxide, diethylaminoethyl chloride, Alkylating agents such as β-chloroethylamine, 3-chloropropylamine, 3-chloropropionitrile and acrylonitrile, and acylating agents such as monochloroacetic acid, acetic anhydride, benzoyl chloride, phenyl isocyanate and p-toluenesulfonyl chloride. Can be mentioned.

Further, various catalysts can be used if necessary. As the catalyst, pyridine, dimethylaminopyridine, 4-piperidinopyridine, dimethylsulfoxide, triethylamine, 1,8-diazabicyclo [5.4.0]
] Bases such as undecene-7-ene can be preferably used.

The reaction conditions differ depending on the substituent-introducing agent, catalyst, etc. used and are not specified, but from the viewpoint of preserving the molecular weight and preventing denaturation / coloration, 100
It is preferred to complete the reaction within 80 hours at a temperature below ° C. The chitin derivative produced by the method for producing a chitin derivative of the present invention can be represented by the following general formula (I).

[0020]

[Chemical 2]

[0021] In the general formula (I), substituents R ₁ and R ₂ are different by introducing a substituent agent used is not particularly limited, as a typical example, a substituted or unsubstituted as R ₁ A substituted alkyl group, an acyl group, a carbamoyl group, a sulfonyl group and an aralkyl group can be substituted with R ₂
Examples thereof include a substituted or unsubstituted alkyl group, an acyl group, a carbamoyl group and a sulfonyl group. R ₁ and R ₂ may each independently take these groups. More specifically, as R ₁ , hydroxyethyl, carboxymethyl, aminoethyl, diethylaminoethyl, cyanoethyl, hydroxypropyl, aminopropyl, dihydroxypropyl, acetyl, benzoyl, carbamoyl, tosyl and trityl groups, and R
Examples of ₂ include hydroxyethyl, carboxymethyl, aminoethyl, diethylaminoethyl, cyanoethyl, hydroxypropyl, aminopropyl, dihydroxypropyl, acetyl, benzoyl, carbamoyl and tosyl groups.

[0022]

The squid soft shell used as a raw material for the chitin derivative in the present invention has a very low content of ash such as calcium and pigments such as astaxanthin as compared with crab / shrimp shells. Therefore, it is possible to simplify the deashing and decolorizing treatments, and it is possible to suppress lowering of the molecular weight of chitin and the formation of side reaction products that occur in these treatment steps.

Further, squid soft shell chitin obtained from squid soft shell is usually highly swelled in a solvent such as pyridine used for chemical modification of a substance. Therefore, the chemical modification can be performed under relatively mild conditions.

[0024]

The present invention will be described in more detail below with reference to examples, but these examples are not intended to limit the present invention.

Example 1 Preparation of Tritylated Chitin 5 g of 200 g of soft squid soft shell washed with tap water and dried
It was crushed to a proper length and immersed in 2 liters of 0.1N hydrochloric acid for 2 hours. Then, hydrochloric acid was removed, 2 liters of 1N sodium hydroxide was added, and the mixture was boiled for 1 hour. After boiling
After removing the sodium hydroxide waste liquor and rinsing it with running water overnight to wash away the alkaline liquor, and further washing twice with distilled water, dry it in a dryer at 70 ° C overnight to obtain 60 g of squid soft-shell chitin. It was The thus obtained squid soft shell chitin was treated with a crusher to obtain white, cotton-like fine squid soft shell chitin.

0.2 g of the obtained fine squid soft-shell chitin was put in 10 ml of pyridine and stirred for 2 minutes with a stirrer to obtain a highly swollen chitin dope. Then, this chitin
2.7 g of chlorotriphenylmethane was added to the flask, 1 g of dimethylaminopyridine was further added, and stirring was continued for 72 hours while heating to 90 ° C. under a nitrogen atmosphere. After completion of the reaction, heating was stopped and the mixture was cooled to room temperature, then the solvent was evaporated and the reaction solution was concentrated. The obtained residue was put into a sufficient amount of ethanol while stirring, and the precipitated solid was collected by filtration, washed with a sufficient amount of ethanol and ether, and dried under reduced pressure. This gave 0.36 g of a pale yellow powder.

Infrared absorption spectrum (IR spectrum) was used to determine the structure and degree of substitution of the obtained compound.
Analysis and elemental analysis were performed. As a result, the infrared absorption spectrum was observed absorption indicates a mono-substituted benzene to 762cm ^-1 and 703cm ^-1, that this compound is tritylated chitin triphenylmethane bound was suggested. In addition, elemental analysis revealed that the degree of tritylation of this compound was 0.85. The results of elemental analysis are shown in Table 1 below. Thus, by using squid soft shell as a raw material, a desired chitin derivative can be obtained from squid soft shell chitin in a one-step reaction, as shown in the following reaction formula.

[0028]

[Chemical 3]

Comparative Example 1 Using crab shell as a raw material, the conventional method (T. Sannan, K. Kurita,
Y. Iwakura, Makromol. Chem., 177, 3589 (1976))
The crab shell chitin was prepared according to the procedure described above and then crushed to 100 mesh. 0.2 g of this crab shell chitin was added to 10 ml of pyridine.
The mixture was put in and stirred with a stirrer. However, 1
Even if stirring was continued for about an hour, no swelling was observed, so stirring was continued for 3 days. There was almost no change in appearance after stirring for 3 days, but 2.7 g of chlorotriphenylmethane and 1 g of dimethylaminopyridine were added to this, and stirring was continued for 72 hours while heating to 90 ° C under a nitrogen atmosphere. It was After the reaction is complete, stop heating and
After cooling at room temperature, the solvent was evaporated and concentrated. The obtained residue was put into a sufficient amount of ethanol, solids were collected by filtration, washed with a sufficient amount of ethanol and ether, and then dried under reduced pressure. As a result, a brown powder was obtained.

When the obtained compound was subjected to IR spectrum analysis and elemental analysis, no absorption characteristic of tritylated chitin was observed, and it was presumed that the raw material chitin was slightly carbonized.

Comparative Example 2 As shown in Comparative Example 1, since the crab shell chitin does not dissolve or swell in the solvent as it is, the conventional method (K.
Kurita, T. Sannan, Y. Iwakura, Makromol. Chem., 1
78, 3197 (1977)) for deacetylation to obtain chitosan. 2 g of the obtained chitosan was dispersed in 400 ml of dimethylformamide, 5.5 g of phthalic anhydride was added, and the mixture was heated at 130 ° C. for 5 hours in a nitrogen atmosphere. The solution obtained by this reaction was poured into ice water, and the formed precipitate was washed with ethanol and ether in that order and then dried to obtain a pale brown phthaloylated chitosan. This phthaloylated chitosan is soluble in pyridine.

2 g of the obtained phthaloylated chitosan was dissolved in 30 ml of pyridine, and 19.2 g of chlorotriphenylmethane was dissolved.
And was heated at 90 ° C. for 24 hours under a nitrogen atmosphere. The solvent was evaporated from the reaction solution, the resulting viscous solution was poured into 120 ml of ethanol, and the produced white solid was collected by filtration. This was washed sequentially with ethanol and ether and dried to obtain 3.6 g of white powder (yield
99%).

2 g of the product thus obtained, 10.8 ml of hydrazine monohydrate and 21.6 ml of distilled water were mixed and heated at 100 ° C. for 15 hours while stirring under a nitrogen atmosphere. After the reaction, the mixture was cooled to room temperature, diluted with 20 ml of distilled water, and evaporated to dryness with a rotary evaporator. After repeating this operation three times, the product was suspended in deionized water, the white suspension was collected by filtration, washed with ethanol and ether successively, and dried to give a white powder 1.5.
g was obtained (yield 84%).

0.5 g of this white product was added to 10 m of 10% dilute acetic acid.
It was dissolved in 1 and diluted with 50 ml of methanol. After 0.4 ml of acetic anhydride was added dropwise to this solution and mixed,
The mixture was allowed to stand at room temperature for 12 hours to obtain a gel-like material. The gel was suspended in 300 ml of methanol and stirred at room temperature for 24 hours, and the suspension was collected by filtration. Then, this suspension was resuspended in distilled water to remove unreacted substances by washing, and the suspension was collected again by filtration and dried. This yields 92%
A reaction product was obtained.

The obtained product was subjected to IR spectrum analysis and elemental analysis to confirm the structure of the product. As a result, it was confirmed that the obtained product was tritylated chitin.

As described above, in order to obtain tritylated chitin from crab shell chitin as a raw material, as shown in the following reaction formula, five extremely complicated steps must be performed. As a result, the total time required for each process is 80 hours even if only the reaction time is taken, and the time required for operations such as washing, filtration and dissolution of the product is more than 100 hours. In addition, the yield throughout the entire process was 73%.

[0037]

[Chemical 4]

Example 2 Preparation of Tosylated Chitin 0.2 g of fine squid soft-shell chitin prepared in the same manner as in Example 1 was added to 10 ml of pyridine, 2.0 g of p-toluenesulfonyl chloride and 0.2 g of dimethylaminopyridine were subsequently added. Add and stir at room temperature for 48 hours under nitrogen atmosphere. The dark yellow liquid thus obtained was poured into ice water and the precipitated suspension was collected by filtration. The suspension was washed successively with ethanol and ether and dried under reduced pressure to obtain 0.3 g of a light brown powder.

When this compound was subjected to IR spectrum analysis and elemental analysis, absorption of a sulfone group derived from a tosyl group was observed at 1174 cm ⁻¹ , and the elemental analysis showed that the degree of tosylation was 81%. confirmed. Table 2 below
The results of elemental analysis are shown in.

Since the tosylated chitin obtained in this Example is soluble in a polar solvent, it can undergo a chemical reaction under mild conditions. Therefore, it is very useful as a precursor for further complicated chemical modification.

Comparative Example 3 Tosylated chitin was produced by the same procedure as in Example 2 using the finely divided crab shell chitin and shrimp shell chitin prepared in the same manner as in Comparative Example 1, respectively. However, in any case, no reaction occurred and tosylated chitin could not be obtained.

Comparative Example 4 To 2.5 g of finely powdered crab shell chitin, 72.5 g of 42% by weight aqueous sodium hydroxide solution was added, and the mixture was dried under reduced pressure at room temperature.
Leave for 3 hours. Then add 125g of ice and stir,
I got alkaline chitin. A solution of 35 g of tosyl chloride in 75 ml of chloroform was added to the obtained alkaline chitin with vigorous stirring. The solution was stirred at 0 ° C. for 1 hour, then at room temperature for 3 hours, then poured into deionized water and the resulting suspension was collected by filtration. The collected suspension was washed with deionized water until the washing solution became neutral, then washed successively with methanol and ether, and then dried under reduced pressure to obtain 4.0 g of a white powder. When this product was subjected to IR spectrum analysis and elemental analysis, the degree of tosylation
It was 75%.

The degree of deacetylation of this product was 0.18 as measured by the conductivity titration method. As a result, deacetylation secondary occurred by changing the crab shell chitin to alkaline chitin, and the purity of tosylated chitin was low. Further, when crab shell chitin is used as a raw material, a large problem is that a large amount of a halogenated solvent such as chloroform is required as described above.

Example 3: Preparation of fully N-acetylated chitin Fine squid soft-shell chitin prepared by the same procedure as in Example 1
0.2 g of methanol was added to 20 ml of methanol, and the mixture was stirred for 5 minutes to swell, then 10 ml of acetic anhydride was added, and stirring was continued at 40 ° C. for 48 hours under a nitrogen atmosphere. The obtained product was put into ice water and left for 2 hours. Then, the precipitated suspension was collected by filtration, washed successively with water and acetone,
It was dried under reduced pressure to obtain 0.2 g of a white powder.

The degree of deacetylation of the chitin before the reaction and the reaction product after the reaction was measured by the conductivity titration method, and it was 0.07 before the reaction and 0.00 after the reaction. That is, 100% N-acetylated chitin was obtained by this reaction. Moreover, it was confirmed from the IR spectrum that the skeleton of chitin was not modified with respect to this reaction product.

The completely N-acetylated chitin thus obtained is a highly pure chitin and is very useful as a starting material for a chemical reaction using chitin as a raw material.

Comparative Example 5 N-acetylation reaction was carried out in the same procedure as in Example 3 using finely ground crab shell chitin (deacetylation degree 0.11) and shrimp shell chitin (deacetylation degree 0.13) as raw materials. I did. However, the degree of deacetylation of chitin after the reaction was 0.11 and 0.13, respectively, and acetylation did not proceed at all by this method.

Comparative Example 6 To 3 g of finely ground crab shell chitin, 75 g of 40% by weight sodium hydroxide solution was added, and the mixture was left under reduced pressure for 3 hours and then iced.
222 g was added and stirred to obtain an alkaline chitin aqueous solution.
Next, this aqueous solution was allowed to stand at 25 ° C. for 77 hours, cooled to 5 ° C., 210 g of ice was added, and hydrochloric acid was added dropwise to lower the pH to 9. This solution was cooled to 0 ° C with acetone-water (
7: 1) The mixture was added dropwise to 5 liters of mixed solvent with stirring to reprecipitate. Next, the precipitate was collected by filtration, the solvent was removed, and then the suspension was resuspended in a cold acetone-water mixed solvent, and a small amount of water was added to eliminate the cloudiness of the liquid. This filtration washing process
Repeated 5 times, finally washed with acetone and dried to obtain water-soluble chitin. 0.44 g of the water-soluble chitin thus obtained was put on 40 g of ice, and the water-soluble chitin was dissolved as the ice melted. Acetic acid 1.44 in the resulting aqueous solution
g and 4.94 g of dicyclohexylcarbodiimide dissolved in 60 ml of dimethylformamide were added, and the mixture was stirred at room temperature.
After stirring for 44 hours, this solution was poured into saturated aqueous sodium hydrogen carbonate solution. The suspension thus produced was collected by filtration, washed successively with water and methanol and then dried to give a white powder. When the obtained product was subjected to conductivity titration and IR spectrum analysis, it was confirmed that the degree of deacetylation was 0.01.

As described above, N-acetylated chitin can be obtained from crab shell chitin by the method of this comparative example, but acetylation has not been achieved 100%, and the process is extremely complicated and a large amount of acetone is required. There are problems such as needing.

Example 4: Preparation of partially O-acetylated chitin 0.2 g of fine squid soft-shell chitin prepared by the same procedure as in Example 1 was added to 20 ml of pyridine, and then 10 m of acetic anhydride was added.
1 and 0.2 g of dimethylaminopyridine were further added, and the mixture was stirred at room temperature for 48 hours under a nitrogen atmosphere. After the reaction was completed, the reaction solution was poured into ice water and left for 2 hours. Then, the precipitated suspension was collected by filtration, washed successively with ethanol and ether, and dried under reduced pressure to give a white powder 0.2
47 g was obtained.

The obtained product was subjected to IR spectrum analysis and elemental analysis. As a result, in the IR spectrum,
Absorption from O- acetyl group 1742 cm ^-1 and 1240 cm ^-1 are observed O- acetyl chitin was confirmed. In addition, elemental analysis confirmed that the degree of acetylation was 2.0. The results of elemental analysis are shown in Table 3 below.

Example 5: Production of fully O-acetylated chitin The same operation as in Example 4 was carried out except that the reaction was carried out under a nitrogen atmosphere at 50 ° C. for 48 hours with stirring.
The white powder obtained as a result was subjected to IR treatment in the same manner as in Example 4.
It was confirmed to be fully acetylated chitin with an acetylation degree of 3.0 when subjected to spectrum and elemental analysis.

In addition to the above Examples 4 and 5, O-acetylation under various conditions was examined. In each case, the degree of acetylation was 2.0 or 3.0,
Although the reason is unknown, it did not take the intermediate value. From these facts, the O-acetylated chitin having an acetylation degree of 2.0 is an O-acetylated chitin in which the primary hydroxyl group at the 6-position is acetylated, and the O-acetylated chitin having an acetylation degree of 3.0 is O-acetylated chitin.
It was confirmed that the -acetylated chitin was a completely O-acetylated chitin in which the secondary hydroxyl group at the 3-position was acetylated in addition to the 6-position hydroxyl group. That is, according to these methods, O-acetylated chitin in which only the 6-position hydroxyl group was acetylated or both 6- and 3-position hydroxyl groups were completely acetylated without requiring strict condition setting. It becomes possible to selectively obtain either O-acetylated chitin.

Comparative Example 7 0.2 g of shrimp shrimp shell chitin which had been miniaturized was put into a mixed solution of 6.5 g of trichloroacetic acid and 3.5 g of 1,2-dichloroethane kept at 15 ° C., and the mixture was stirred for 2 hours to be dissolved. 4 ° C
It was cooled to room temperature and allowed to stand for 24 hours. 1.1m acetic anhydride in this solution
1 was added dropwise, the mixture was stirred for 1 hour while maintaining the temperature at 15 ° C, and then allowed to stand at 4 ° C for 24 hours to carry out the reaction.
After the reaction was completed, the reaction solution was poured into ice water, and the resulting suspension was collected by filtration and washed successively with ethanol and ether. After washing, white powder is obtained by drying under reduced pressure 0.2
35 g were obtained.

This product was subjected to IR spectrum analysis and elemental analysis. As a result, 1742 derived from O-acetyl group
absorption in cm ^-1 and 1240 cm ^-1 was observed, but it is O- acetylated chitin was observed, the chlorine content is zero.
It was as high as 37%, and it was inferred that a side reaction due to the use of trichloroacetic acid as a solvent had occurred, and the purity was low.

[0056]

INDUSTRIAL APPLICABILITY As described above, according to the method for producing a chitin derivative of the present invention, the steps for producing a chitin derivative are greatly simplified, and a high quality chitin derivative can be obtained relatively easily and in good yield. it can. In addition, the reaction itself does not require harsh conditions, so it is safe, and in addition, a chitin derivative having a relatively high molecular weight with little cleavage of the chitin main chain, and having little denaturation or coloration can be obtained.

The chitin derivatives obtained by the method of the present invention have a very wide range of uses. In particular, the chitin derivative in which only the primary hydroxyl group at the 6-position of chitin is chemically modified, such as the tosylated chitin of Example 2, is more activated at the 6-position due to tosylation, and thus the reactivity is improved. It becomes easy to chemically modify only the 6-position with another compound. In addition, the tritylated chitin of Example 1 and the partially O-acetylated chitin of Example 4 were obtained by chemically modifying the hydroxyl group at the 3-position with another substituent, and then optionally adding the trityl group at the 6-position. By removing the acetyl group and the acetyl group, a chitin derivative in which only the hydroxyl group at the 3-position is selectively chemically modified can be easily obtained. As described above, the chitin derivative obtained by chemically modifying the primary hydroxyl group at the 6-position with various substituents according to the present invention can be preferably used as a starting material when selectively chemically modifying only the 3-position and the 6-position. it can. These chitin derivatives include compounds expected to be effective as antiviral substances and anticoagulants. Many of these chitin derivatives are soluble in organic solvents and can easily form a membrane, and are expected to be used as a selectively permeable membrane.

Complete N-acetylated chitin of Example 3, partially O-acetylated chitin of Example 4, complete O of Example 5.
-Acetylated chitin is acetylated at a specific position, and is useful when structural modification is required when chemical modification is performed using chitin as a starting material. Further, it is also suitably used as a standard substance in various analyses.

Claims (5)

[Claims] 1. A method for producing a chitin derivative in which squid soft shells are decalcified and deproteinized, then swollen with a solvent, and then a substituent-introducing agent is added and reacted. 2. The method according to claim 1, wherein the chitin derivative is represented by the following general formula (I). [Chemical 1] (Here, R ₁ represents a substituted or unsubstituted alkyl group, an acyl group, and a carbamoyl group, a sulfonyl group, and an aralkyl group, and R ₂ represents a substituted or unsubstituted alkyl group, an acyl group, and a carbamoyl group and a sulfonyl group. Represents) 3. The group in which the solvent comprises pyridine, dimethyl sulfoxide, n-methylpyrrolidone, m-cresol, dimethylacetamide, dimethylformamide, hexamethylphosphoramide, methanol, ethanol and dichloroacetic acid. The method according to claim 1, wherein the method is at least one organic solvent selected from the group consisting of: 4. The method according to claim 1, wherein the substituent-introducing agent is at least one selected from alkyl halides, carboxylic acid anhydrides, acyl halides, sulfonyl halides, aralkyl halides, and epoxy compounds. 5. Chitin as an intermediate in the method for producing a chitin derivative according to claim 1, which is obtained by subjecting squid soft shells to decalcification treatment and deproteinization treatment.