Method of producing n,s-containing, chitosan-based polymer

FIELD: chemistry.

SUBSTANCE: present invention relates to a method of producing a N,S-cyclo-containing chitosan derivative. Described is a method of producing a chitosan-based N,S-cyclo-containing polymer (I) which contains in the macrochain 1-oxa-6-thia-4,8-diazocycloundecane fragments: I, by reacting chitosan with formaldehyde and a S-containing compound, characterised by that the S-containing compound used is hydrogen sulphide, the formaldehyde solution is pre-saturated with H2S and the reaction is carried out with molar ratio chitosan: formaldehyde: hydrogen sulphide of 1:2:1, at temperature of 0-60°C in a chloride medium for 24 hours.

EFFECT: obtaining modified chitosan which exhibits properties of a highly efficient heavy metal sorbent for waste water treatment, an extractant for separating rare, noble and precious metals and a complexing agent for biological molecules.

1 tbl, 3 ex

 

The present invention relates to organic chemistry, in particular to a method for producing N,S-cicloturismo derivative of chitosan (I)having the structural formula:

where n=50-70%, m=30-50%.

Currently, chitosan and its derivatives are considered as soil builders: company Ecogel produces patented chitosan containing drug "anti-Stress", designed to accelerate engraftment and acclimatization imported or transplanted plants http://www.ecogel.ru).

Like N,S-cyclododecane biopolymers having glucopyranose 1-oxa-6-thia-4,8-diazocyclopentadiene heterocycles are of interest as highly effective sorbents of heavy metals to wastewater treatment, extractants for the separation of rare, precious and precious metals, as well as selective complexing agents of biological molecules (T.Becker, .Schlaak, .Strasdeit // Reactive and Functional Polymers, 2000, 44, p.289-298. Z. Cao, H. Ge, S. Lai // European Polymer Journal, 2001, 37, p.2141-2143).

It is known that chitosan and its derivatives are promising polysaccharide materials to create ion-exchange membranes used in ultrafiltration and dialysis, and their complexing ability can be used for selective extraction of some metals from seawater (Evert, Antiseptci// USP, 2001, CH, No. 1, p.72-87). Chitosan and its phosphate derivatives, in particular phosphate chitosan can be used as biocompatible materials (Wang X., Ma J., Wang Y., He, B. // Biomaterials, 2001, v.22, no.16, p.2247), sorbents for the extraction of uranium (Sakaguchi T., Hirokoshi T., Nakajima A. // Agric. Biol. Chem., 1981, v.45, no.10, p.2191), chiral matrices to create a metal-complex catalysts (E. Guibal // Prog. Polym. Sci., 2005, v.30, no.1, p.71).

According to literature data, the chemical modification of chitosan can be carried out for all functional groups. Thus, a method of obtaining N,O-carboxymethyl-N,O-sulfotransferase chitosan (Zhao Xia, LV Zhihua, XU Jiamin, YU Guangli // Journal of Ocean University of Qingdao, 2003, v.2, no.1, p.69-74)with inhibitory activity against platelet blood:

There are examples of modifications of chitosan solely by the primary amino group of the polysaccharide. A method of obtaining N-alkyl derivatives of chitosan, which is based on the interaction of chitosan with aliphatic aldehydes by introduction of alkyl substituents on the amino group of the original polymer via Schiff's base (Keisuke Kurita, Satoko Mori, Yasuhiro Nishiyama, Manabu Harata // Polymer Bulletin, 2002, 48, p.159-166). It was shown that with increasing alkyl radical increases antibacterial activity of derivatives of chitosan (Chun But Kim, Jang Won Choi, Heung Jae Chun, Suk Kyu Choi // Polymer Bulletin, 1997, v.38, no.4, p.387-393).

The closest prototype of the method is based on the interaction of chitosan with formaldehyde and a thiol with obtaining sulfur-containing derivative, having grafted linear N-alkylthiomethyl group (Tanja Becker, Michael Schlaak, Henry Strasdeit // Reactive and Functional Polymers, 2000, 44, p.289-298), which selectively absorbs cadmium in the presence of salts of Nickel and zinc.

Thus, in the literature there are no data on the modification of chitosan on the amino group with obtaining N,S-containing cyclic derivative of chitosan.

The authors faced the problem of obtaining cyclic N,S-containing derivative of chitosan interaction timetreasure reagent "CH2O-H2S ' (A Wohl. Berichte, 1886, 19, 2344) with the primary amino groups of the original biopolymer. Information about how to obtain the above cyclic derivative such method in the literature are missing.

This goal is achieved by the interaction of saturated hydrogen sulfide aqueous 37%solution of formaldehyde with hydrochloric acid solution of chitosan taken in a molar ratio of the initial reagents chitosan:formaldehyde:hydrogen of 1:2:1 at a temperature of 0-60°C and stirring for 24 hours. The reaction mixture is neutralized with a weak solution of NaOH, the modified polymer is precipitated by 70%ethanol and centrifuged. When this clause is to obtain N,S-cyclododecane derivative of chitosan (I), in macrocopy which along with 2-amino-D-pyranose fragments are 1-oxa-6-thia-4,8-diazacyclooctadecane fragments. The reaction proceeds according to the scheme:

where n=50-70%, m=30-50%.

We studied the effect of modified chitosan (I) and its salts based on oxalic (C2H2About4) and ascorbic (C6H8About6) acids on the growth of seedlings and the development of root rot on wheat plants. The objects of the study were treated with aqueous solutions of sample (I) and its salts with a concentration of 1%, 0.1% and 0.01 percent. The results are shown in table 1. The value of the parameter characterizing the ratio of the length of the sheet to the length of the root.

Table 1
The effect of the product (I) and its salts on the growth and development of root rot on wheat plants
Rate/concentrationControlThe sample II·C2H2O4I·C6H8O6
The strength of growth/1%1,050,790,681,19
0,1%1,050,970,920,92
0,01%1,051,081,00,91
The development of root rot/
1%39,914,517,819,2
0,1%14,117,80
0,01%6,614,72,8

It is shown that the product of (I) at a concentration of 0.01% will influence the growth of seedlings of wheat, and on the suppression of root rot affects both itself and its salts in concentrations of from 1.0% to 0.01%. Adduct with ascorbic acid in a concentration of 0.1% inhibits the development of root rot completely. As a result of the studies revealed that the product timestribune chitosan exhibits good fungicidal activity is, he absolutely environmentally safe and commercially available.

Significant differences of the proposed method

In the proposed method is the interaction of saturated hydrogen sulfide formaldehyde - dielectrophoresis reagent capable of simultaneously interact with two amino groups of chitosan - (1-4)-2-amino-2-deoxy-D-glycolysation. As a result, this method allows to obtain a cyclic N,S-containing derivative of chitosan (I) with 1-oxa-6-thia-4,8-diazacyclooctadecane fragments in macrocopy, details of which in the literature are missing.

Unlike the prototype (Tanja Becker, Michael Schlaak, Henry Strasdeit // Reactive and Functional Polymers, 2000, 44, p.289-298) the reaction takes place with the formation of S,N-heterocycles on chitosan matrix.

The advantages of the proposed method

The method allows to obtain N,S-cyclododecane derivative of chitosan (I), which forms a stable hydrogel, the synthesis of which is not described in literature, and is easy to experiment.

The method is illustrated by example

Example 1. In a three-neck flask equipped with stirrer, reflux condenser and bubbler temperature-controlled at a predetermined temperature, loaded with 3.3 ml of 37% (10 mmol) of formalin, 30 min was barbotirovany hydrogen (derived from the estimated number of Na2S and HCl) with the formation of a mixture of CH2O and H2S is a rate of 2:1. Then the reaction mass was added dropwise 0.8 g (5 mmol) of chitosan dissolved in 100 ml of 2%HCl. The mixture was stirred at 0°C for 24 hours. The reaction mass was neutralized with NaOH solution to pH=7, the modified chitosan was besieged by 70%ethanol in the ratio by volume of 1:3 by adding dropwise concentrated solution of NaCI. The precipitated polymer was centrifuged and washed three times with 70%alcohol, dried in the air. The result was obtained 1.04 g of N,S-cicloturismo derivative of chitosan (I) with 30%functionalization.

Example 2. In a three-neck flask equipped with stirrer, reflux condenser and bubbler temperature-controlled at a predetermined temperature, downloaded the calculated amount of 37%formalin, 30 min was barbotirovany hydrogen (derived from the estimated number of Na2S and HCl) with the formation of a mixture of CH2O and H2S in the ratio 2:1. Then the reaction mass was added dropwise estimated number of mole of chitosan (0.8 g)dissolved in 100 ml of 2%HCl. The mixture was stirred at 20°C for 24 hours. The reaction mass was neutralized with NaOH solution to pH 7, the modified chitosan was besieged by 70%ethanol in the ratio by volume of 1:3 by adding dropwise concentrated solution of NaCI. The precipitated polymer was centrifuged and washed three times with 70%alcohol, dried in the air. In financial p is Tata obtained 1.20 g of N,S-cicloturismo derivative of chitosan (I) 35%functionalization.

Example 3. In a three-neck flask equipped with stirrer, reflux condenser and bubbler temperature-controlled at a predetermined temperature, downloaded the calculated amount of 37%formalin, 30 min was barbotirovany hydrogen (derived from the estimated number of Na2S and HCl) with the formation of a mixture of CH2O and H2S in the ratio 2:1. Then the reaction mass was added dropwise estimated number of mole of chitosan (0.8 g)dissolved in 100 ml of 2%HCl. The mixture was stirred at 60°C for 24 hours. The reaction mass was neutralized with NaOH solution to pH 7, the modified chitosan was besieged by 70%ethanol in the ratio by volume of 1:3 by adding dropwise concentrated solution of NaCI. The precipitated polymer was centrifuged and washed three times with 70%alcohol. The result was obtained 1.04 g of N,S-cicloturismo derivative of chitosan (I) 50%functionalization.

The spectral characteristics of the1(1IR spectra were obtained on a spectrophotometer "Specord 75IR" in suspension in vaseline oil. One-dimensional NMR spectra1H,13C-and two-dimensional spectra (HSQC, COSY) of compound I registered on a “Bruker Avance 400”, internal standard TMS, solvent DMSO-d6.)

N,S-cicloturismo derivative of chitosan (I):

The connection I

The IR spectrum v cm-1: 750, 1050, 1170, 1620, 2900, 3200.

An NMR spectrum1N, D22).

An NMR spectrum13With, ppm, δ: 55.9 d, (C-2); 57.8 t (C-7); 57.9 t (C-6); 71.8 (C-3), 75.9 (C-5), 77.7 (C-4), 97.5 (C-1).

where n=50-70%, m=30-50%.

The method of obtaining the N,S-cicloturismo polymer (I) based on chitosan containing macrocopy 1-oxa-6-thia-4,8-diazacyclooctadecane fragments

the interaction of chitosan with formaldehyde and S-containing compound, characterized in that as S-containing compounds using hydrogen sulfide, formaldehyde solution is pre-saturated with H2S and the reaction is carried out at a molar ratio of chitosan - formaldehyde - hydrogen of 1:2:1, at a temperature 0÷60°C in hydrochloric acid environment within 24 hours



 

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3 tbl, 3 ex

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