阅读说明：本技术 一种抗hiv活性肉桂酸/邻氯苯甲酸蔗渣木聚糖双酯的合成方法 (Synthetic method of anti-HIV (human immunodeficiency virus) active cinnamic acid/o-chlorobenzoic acid bagasse xylan diester ) 是由 李和平 葛文旭 杨锦武 李明坤 张淑芬 郑光绿 耿恺 柴建啟 杨莹莹 于 2019-10-22 设计创作，主要内容包括：本发明公开了一种抗HIV活性肉桂酸/邻氯苯甲酸蔗渣木聚糖双酯的合成方法。以蔗渣木聚糖为主要原料,以肉桂酰氯为酯化剂,三乙胺为催化剂,首先在二氯甲烷溶剂中经第一步酯化反应合成了肉桂酸蔗渣木聚糖酯；再以邻氯苯甲酰氯为酯化剂,吡啶与<I>N</I>,<I>N’</I>-二异丙基碳二亚胺(DIC)为复合催化剂,经过第二步复合催化酯化反应合成肉桂酸/邻氯苯甲酸蔗渣木聚糖双酯。本发明通过两次酯化反应,产物兼具肉桂酸蔗渣木聚糖酯和邻氯苯甲酸蔗渣木聚糖酯的性质,生物活性增强,拓宽了木聚糖衍生物在生物、医药等领域的应用范围。(The invention discloses a method for synthesizing anti-HIV active cinnamic acid/o-chlorobenzoic acid bagasse xylan diester. The method comprises the following steps of (1) synthesizing bagasse xylan cinnamate by taking bagasse xylan as a main raw material, cinnamoyl chloride as an esterifying agent and triethylamine as a catalyst through a first-step esterification reaction in a dichloromethane solvent; then o-chlorobenzoyl chloride is used as esterifying agent, pyridine and N , N' and (3) synthesizing cinnamic acid/o-chlorobenzoic acid bagasse xylan diester through a second step of composite catalytic esterification reaction by using diisopropyl carbodiimide (DIC) as a composite catalyst. Through two esterification reactions, the product has the properties of the cinnamic acid bagasse xylan ester and the o-chlorobenzoic acid bagasse xylan ester, the biological activity is enhanced, and the application range of the xylan derivative in the fields of biology, medicine and the like is widened.)

1. A synthetic method of anti-HIV activity cinnamic acid/o-chlorobenzoic acid bagasse xylan diester is characterized by comprising the following specific steps:

(1) placing 20 ~ 25g of bagasse xylan into a vacuum constant-temperature drying oven at 50 ℃ for drying for 24 hours to obtain dry-based bagasse xylan;

(2) weighing 10 ~ 15g cinnamoyl chloride in a 50mL beaker, adding 20 ~ 30mL analytical pure dichloromethane, stirring at room temperature for 5 ~ 8 minutes to obtain an esterifying agent solution, and pouring the esterifying agent solution into a 100mL constant-pressure dropping funnel for later use;

(3) weighing 15 ~ 20g of the dry bagasse xylan obtained in the step (1), placing the dry bagasse xylan into a 250mL four-neck flask provided with a stirrer, a thermometer and a reflux condensing device, sequentially adding 30 ~ 40mL of analytically pure dichloromethane and 3 ~ 4mL of analytically pure triethylamine, and stirring at room temperature for 20 ~ 30 minutes to obtain a bagasse xylan activation solution;

(4) heating the system in the step (3) to 60 ~ 65 ℃, starting to dropwise add the esterifying agent solution prepared in the step (2), controlling the dropwise adding time to be 3 ~ 4 hours, continuing to react for 1 ~ 2 hours after the dropwise adding of the esterifying agent solution is finished, and cooling the materials to room temperature;

(5) adding 30 ~ 40mL of analytically pure acetone into the material obtained in the step (4), uniformly stirring, precipitating for 40 ~ 50 minutes, filtering, washing with 20 ~ 30mL of deionized water and 20 ~ 30mL of analytically pure absolute ethyl alcohol in sequence, and performing suction filtration for 2 ~ 3 times, putting the filter cake into a watch glass, and drying in a vacuum constant-temperature drying oven at 50 ℃ for 24 hours to obtain the bagasse xylan ester cinnamate;

(6) sequentially adding 5 ~ 10g of o-chlorobenzoic acid and 50 ~ 60mL of 3% ~ 5% by mass sodium hydroxide solution into a 250mL four-neck flask provided with a stirrer, a thermometer and a reflux condensing device, and stirring at room temperature for 30 ~ 50 minutes to obtain an o-chlorobenzoic acid sodium salt solution;

(7) weighing 20 ~ 25g of the bagasse xylan ester cinnamate obtained in the step (5), adding the bagasse xylan ester cinnamate into the sodium o-chlorobenzoate solution obtained in the step (6), stirring at room temperature for 40 ~ 60 minutes, adding 30 ~ 40mL of hydrochloric acid with the mass fraction of 1% ~ 5% to adjust the pH of the reaction solution to 6 ~ 7, adding 2 ~ 3mL of analytically pure pyridine and 1 ~ 2.5mL of analytically pure pyridine, and stirring at room temperature for 40 ~ minutesN,N'Heating Diisopropylcarbodiimide (DIC) to 50 ~ 60 deg.C, reacting under stirring for 4 ~ 6 hr, adjusting pH to 4 ~ 5 with 40 ~ 50mL 5% hydrochloric acid solution, and cooling to room temperatureStirring for 30 ~ 60 min;

(8) pouring the material obtained in the step (7) into a 100mL beaker, adding 30 ~ 50mL of analytically pure absolute ethyl alcohol for precipitation for 30 ~ 50 minutes, filtering, washing with 20 ~ 30mL of deionized water and 20 ~ 30mL of analytically pure absolute ethyl alcohol respectively in sequence, performing suction filtration for 2 ~ 3 times, putting a filter cake into a watch glass, and drying in a vacuum constant-temperature drying oven at 60 ℃ for 24 hours to obtain the cinnamic acid/o-chlorobenzoic acid bagasse xylan diester.

Technical Field

The invention relates to the field of fine chemical engineering, in particular to a method for synthesizing anti-HIV active cinnamic acid/o-chlorobenzoic acid bagasse xylan diester.

Background

AIDS spreads rapidly in the world, and seriously threatens the health of human beings and the development of society. The complicated molecular structure of xylan endows the xylan with unique biological activity, and particularly, the great activity of xylan in resisting HIV virus attracts the attention of researchers at home and abroad. The xylan has poor water solubility and low activity, and the defects of the xylan can be compensated through chemical modification such as esterification, so that the biological activity of the xylan is improved. Because the study on the space structure-activity relationship of the xylan esterified derivatives is difficult, and related studies mainly focus on xylan mono-esterified derivatives such as synthetic xylan sulfate, xylan carboxylate and the like, the study on xylan di-esterified derivatives still stays at the beginning stage.

Esterification modification of xylan is one of the mature chemical modification methods of xylan, and after esterification modification, the water solubility, thermal stability and antiviral activity of xylan are obviously improved. Researches show that the bagasse xylan ester cinnamate in the bagasse xylan monoesterified derivative has the effect of inhibiting AIDS virus replication, and the o-chlorobenzoic acid bagasse xylan ester has the effect of resisting HIV. But the biological activity generated by the mono-esterified derivatives is limited, the bagasse xylan is subjected to double-esterification modification, and two anti-HIV active groups, namely cinnamic acid and o-chlorobenzoic acid, are introduced simultaneously to obtain the bagasse xylan double-esterified derivatives with double activity.

The method comprises the steps of taking bagasse xylan as a main raw material, cinnamoyl chloride as an esterifying agent and triethylamine as a catalyst, and synthesizing cinnamic acid bagasse xylan ester through a first-step esterification reaction in a dichloromethane solvent; and then synthesizing the cinnamic acid/o-chlorobenzoic acid bagasse xylan diester through a second step of composite catalytic esterification reaction by using o-chlorobenzoyl chloride as an esterifying agent and pyridine and N, N' -Diisopropylcarbodiimide (DIC) as a composite catalyst. The product has the properties of the cinnamic acid bagasse xylan ester and the o-chlorobenzoic acid bagasse xylan ester, and the biological activity is enhanced.

Disclosure of Invention

The invention aims to overcome the problems of insufficient anti-HIV activity and the like of bagasse xylan single-modified derivatives, and provides a synthetic method of anti-HIV activity cinnamic acid/o-chlorobenzoic acid bagasse xylan diester.

The method comprises the following specific steps:

(1) and (3) drying 20-25 g of bagasse xylan in a vacuum constant-temperature drying oven at 50 ℃ for 24 hours to obtain the dry-based bagasse xylan.

(2) Weighing 10-15 g of cinnamoyl chloride into a 50mL beaker, adding 20-30 mL of analytically pure dichloromethane, stirring at room temperature for 5-8 minutes to obtain an esterifying agent solution, and pouring into a 100mL constant-pressure dropping funnel for later use.

(3) Weighing 15-20 g of the dry-based bagasse xylan obtained in the step (1), placing the dry-based bagasse xylan into a 250mL four-neck flask provided with a stirrer, a thermometer and a reflux condensing device, sequentially adding 30-40 mL of analytically pure dichloromethane and 3-4 mL of analytically pure triethylamine, and stirring at room temperature for 20-30 minutes to obtain the bagasse xylan activating solution.

(4) And (3) heating the system in the step (3) to 60-65 ℃, starting to dropwise add the esterifying agent solution prepared in the step (2), and controlling the dropwise adding time to be 3-4 hours. And after the esterification agent solution is dripped, continuously reacting for 1-2 hours, and cooling the material to room temperature.

(5) And (3) adding 30-40 mL of analytically pure acetone into the material obtained in the step (4), uniformly stirring, precipitating for 40-50 minutes, filtering, washing with 20-30 mL of deionized water and 20-30 mL of analytically pure absolute ethyl alcohol in sequence, and performing suction filtration for 2-3 times. And (3) putting the filter cake into a watch glass, and drying the watch glass in a vacuum constant-temperature drying oven at 50 ℃ for 24 hours to obtain the cinnamic acid bagasse xylan ester.

(6) Sequentially adding 5-10 g of o-chlorobenzoic acid and 50-60 mL of 3-5% sodium hydroxide solution by mass fraction into a 250mL four-neck flask provided with a stirrer, a thermometer and a reflux condensing device, and stirring at room temperature for 30-50 minutes to obtain an o-chlorobenzoic sodium formate solution.

(7) And (3) weighing 20-25 g of the bagasse xylan ester cinnamate obtained in the step (5), adding the bagasse xylan ester cinnamate into the sodium o-chlorobenzoate obtained in the step (6), stirring at room temperature for 40-60 minutes, adding 30-40 mL of hydrochloric acid with the mass fraction of 1% -5% to adjust the pH of the reaction solution to 6-7, adding 2-3 mL of analytically pure pyridine and 1-2.5 mL of analytically pure N, N' -Diisopropylcarbodiimide (DIC), heating to 50-60 ℃, and reacting for 4-6 hours under stirring. After the reaction is finished, the pH value of the system is adjusted to 4-5 by using 40-50 mL of hydrochloric acid solution with the mass fraction of 5%, the temperature of the system is reduced to room temperature, and stirring is continued for 30-60 minutes.

(8) And (3) pouring the material obtained in the step (7) into a 100mL beaker, adding 30-50 mL of analytically pure absolute ethyl alcohol, precipitating for 30-50 minutes, filtering, washing with 20-30 mL of deionized water and 20-30 mL of analytically pure absolute ethyl alcohol respectively in sequence, and performing suction filtration for 2-3 times. And (3) putting the filter cake into a watch glass, and drying the filter cake in a vacuum constant-temperature drying oven at 60 ℃ for 24 hours to obtain the cinnamic acid/o-chlorobenzoic acid bagasse xylan diester.

(9) And (3) determining the esterification substitution degree of the final product cinnamic acid/o-chlorobenzoic acid bagasse xylan diester obtained in the step (8) by adopting an acid-base titration method, wherein the method comprises the following steps: about 0.5g of the product sample was accurately weighed into a 250mL Erlenmeyer flask, 5mL deionized water was added, and then 3 drops of phenolphthalein indicator were added dropwise. 2.5mL of 0.5mol/L sodium hydroxide solution was added and shaken. Saponification was performed at room temperature for 1 hour with shaking. The stopper and the inner wall of the conical flask are washed by 10mL of deionized water, and then the end point is obtained by titrating to colorless by using 0.5mol/L hydrochloric acid standard solution. Recording the volume V of the standard solution of hydrochloric acid consumed₁. Under the same condition, blank titration is carried out by using bagasse xylan before esterification, and the volume V of the consumed hydrochloric acid standard solution is recorded₀. The Degree of Substitution (DS) of esterification of the target product is calculated according to the following formula:

in the formula:

W_Cthe mass fraction of ester carbonyl groups in the doubly esterified bagasse xylan is percent;

V₀-titrating the amount of bagasse xylan in mL using HCI standard solution;

V₁-titrating the amount of standard solution of hydrochloric acid in mL for the target product;

C_HCl-the concentration of the hydrochloric acid standard solution in mol/L;

m is the mass of the target product sample in g;

DS-degree of substitution of the bis-esterified bagasse xylan derivative, i.e. the target product;

m-relative molecular mass of the acyl anhydroxylose graft derivative units.

The final product cinnamic acid/o-chlorobenzoic acid bagasse xylan diester is synthesized through two esterification reactions. The obtained target product not only improves the physicochemical property of the original bagasse xylan, but also greatly enhances the anti-HIV activity of the bagasse xylan by introducing two active groups in cinnamic acid and o-chlorobenzoic acid.

Drawings

FIG. 1 is an SEM photograph of raw bagasse xylan.

Figure 2 is an SEM photograph of cinnamic acid/o-chlorobenzoic acid bagasse xylan diester.

FIG. 3 is an IR chart of raw bagasse xylan.

Figure 4 IR diagram of cinnamic acid/o-chlorobenzoic acid bagasse xylan diester.

Figure 5 is an XRD pattern of raw bagasse xylan.

Figure 6 is an XRD pattern of cinnamic acid/o-chlorobenzoic acid bagasse xylan diester.

FIG. 7 shows TG and DTG curves of raw bagasse xylan.

Figure 8 is a TG and DTG curve for cinnamic acid/o-chlorobenzoic acid bagasse xylan diester.

Detailed Description