阅读说明：本技术 一种作为保鲜剂的绿原酸衍生物及其制备方法 (Chlorogenic acid derivative used as preservative and preparation method thereof ) 是由 谢天龙 于 2021-01-19 设计创作，主要内容包括：本发明公开了一种作为保鲜剂的绿原酸衍生物及其制备方法,本发明属于有机合成技术领域；所述的制备方法如下：惰性气体保护下,在碱性溶液中,在温度50～80℃下,搅拌反应10～15h,绿原酸与3-氨基-5-甲基异恶唑反应,获得绿原酸衍生物粗产物,将粗产物经硅胶柱纯化、高效液相色谱分离即得到绿原酸衍生物；经实验证明,该化合物对芒果具有一定的防腐败效果,使芒果能够保持很好的新鲜度,同时,还能够很好地抑制病杀灭水果中的病原菌,明显提高水果的保鲜效果；本发明的制备方简单、操作方便、可广泛用于水果市场、工厂以及家庭的水果保鲜。(The invention discloses a chlorogenic acid derivative used as a preservative and a preparation method thereof, belonging to the technical field of organic synthesis; the preparation method comprises the following steps: under the protection of inert gas, stirring and reacting for 10-15 h in an alkaline solution at the temperature of 50-80 ℃, reacting chlorogenic acid with 3-amino-5-methylisoxazole to obtain a crude product of a chlorogenic acid derivative, and purifying the crude product by a silica gel column and separating the crude product by high performance liquid chromatography to obtain the chlorogenic acid derivative; experiments prove that the compound has a certain anti-rot effect on mangos, so that the mangos can keep good freshness, and meanwhile, pathogenic bacteria in fruits can be well inhibited and killed, and the fresh-keeping effect of the fruits is obviously improved; the invention has simple preparation method and convenient operation, and can be widely used for fruit fresh-keeping in fruit markets, factories and families.)

1. A chlorogenic acid derivative as an antistaling agent, characterized in that the derivative has a molecular structure of formula (I):

2. a preparation method of chlorogenic acid derivatives used as an antistaling agent is characterized by comprising the following steps:

under the protection of inert gas, dissolving chlorogenic acid in an organic solvent in an anhydrous reaction container, adding 3-amino-5-methylisoxazole, adding alkali as a catalyst, mixing and stirring for 30min, heating to 50-80 ℃, stirring for reaction for 10-15 h, detecting complete reaction by TLC, adding saturated salt solution into a reaction solution for washing, extracting with ethyl acetate, combining organic phases, drying with anhydrous sodium sulfate, concentrating to obtain a concentrated solution, adding silica gel into the concentrated solution for mixing with a sample, drying and mixing with the silica gel at 30-40 ℃, performing silica gel column elution chromatography, collecting column chromatography liquid, concentrating at 40-45 ℃ to dryness to obtain an extract, further purifying the obtained extract by using a high performance liquid chromatography, collecting eluent according to an ultraviolet detection result, and performing reduced pressure concentration to obtain a chlorogenic acid derivative;

the organic solvent is methanol, ethanol, isopropanol, dichloromethane, carbon tetrachloride or dichloromethane;

the mass volume ratio of the chlorogenic acid to the organic solvent is 1 (5-20) g/mL;

the molar ratio of the chlorogenic acid to the 3-amino-5-methylisoxazole is 1 (1.2-2.5);

the alkali is sodium hydroxide, sodium carbonate, potassium carbonate, triethylamine, pyridine or pyrrole;

the silica gel column eluent is a mixture of ethyl acetate and petroleum ether, wherein the volume ratio of the petroleum ether to the ethyl acetate is 10-50: 1.

3. The method for preparing chlorogenic acid derivatives as antistaling agent according to claim 2, comprising the following steps:

under the protection of inert gas, 20g of chlorogenic acid is dissolved in 100mL of methanol in an anhydrous reaction vessel, 10.5g of 3-amino-5-methylisoxazole is added, sodium hydroxide is added as a catalyst, the mixture is stirred for 30min, the temperature is raised to 80 ℃, the mixture is stirred and reacted for 15h, the TLC detection reaction is complete, adding saturated saline solution into the reaction solution, washing, extracting with ethyl acetate, combining organic phases, drying with anhydrous sodium sulfate, concentrating to obtain concentrated solution, adding silica gel into the concentrated solution, mixing the mixture with the silica gel, drying the mixed silica gel at 30-40 ℃, performing elution chromatography by using a silica gel column, collecting column chromatography liquid, concentrating the mixture at 40-45 ℃ until the mixture is dried to obtain an extract, further purifying the obtained extract by using a high performance liquid chromatography, collecting eluent according to an ultraviolet detection result, and performing reduced pressure concentration to obtain the chlorogenic acid derivative.

Technical Field

The invention belongs to the technical field of organic compound preparation, and relates to a chlorogenic acid derivative used as an antistaling agent and a preparation method thereof.

Background

Chlorogenic acid is a phenylpropanoid compound generated by a shikimic acid pathway in the aerobic respiration process of a plant body, and is always highly concerned by students after being successfully extracted from apples for the first time in the 50 th of the 20 th century. Chlorogenic acid is widely used as an antistaling agent and a preservative in food and chemical industries. In order to develop a preservative with better performance, a great deal of research is carried out on chlorogenic acid by scholars, for example, patent CN105325830B discloses a graft of chlorogenic acid and gelatin, which has certain efficacy in preservation. However, gelatin itself is crosslinked, and becomes a gel at normal temperature to form a water-insoluble film, and as the temperature is increased and the time is prolonged, the spatial crosslinking point of gelatin is strong, and these defects of gelatin cause much trouble in subsequent processing.

Disclosure of Invention

In order to solve the technical problems, the invention provides a chlorogenic acid derivative used as an antistaling agent, which has a molecular structure shown in a formula (I):

another object of the present invention is to provide a method for preparing chlorogenic acid derivatives as an antistaling agent, comprising the steps of:

under the protection of inert gas, dissolving chlorogenic acid in an organic solvent in an anhydrous reaction container, adding 3-amino-5-methylisoxazole, adding alkali as a catalyst, mixing and stirring for 30min, heating to 50-80 ℃, stirring for reaction for 10-15 h, detecting complete reaction by TLC, adding saturated salt solution into a reaction solution for washing, extracting with ethyl acetate, combining organic phases, drying with anhydrous sodium sulfate, concentrating to obtain a concentrated solution, adding silica gel into the concentrated solution for mixing with a sample, drying and mixing with the silica gel at 30-40 ℃, performing silica gel column elution chromatography, collecting column chromatography liquid, concentrating at 40-45 ℃ to dryness to obtain an extract, further purifying the obtained extract by using a high performance liquid chromatography, collecting eluent according to an ultraviolet detection result, and performing reduced pressure concentration to obtain a chlorogenic acid derivative;

the organic solvent is methanol, ethanol, isopropanol, dichloromethane, carbon tetrachloride or dichloromethane;

the mass volume ratio of the chlorogenic acid to the organic solvent is 1 (5-20) g/mL;

the molar ratio of the chlorogenic acid to the 3-amino-5-methylisoxazole is 1 (1.2-2.5);

the alkali is sodium hydroxide, sodium carbonate, potassium carbonate, triethylamine, pyridine or pyrrole;

the silica gel column eluent is a mixture of ethyl acetate and petroleum ether, wherein the volume ratio of the petroleum ether to the ethyl acetate is (10-50): 1.

According to a preferred embodiment of the above preparation method, the method comprises the following steps:

under the protection of inert gas, 20g of chlorogenic acid is dissolved in 100mL of methanol in an anhydrous reaction vessel, 10.5g of 3-amino-5-methylisoxazole is added, sodium hydroxide is added as a catalyst, the mixture is stirred for 30min, the temperature is raised to 80 ℃, the mixture is stirred and reacted for 15h, the TLC detection reaction is complete, adding saturated saline solution into the reaction solution, washing, extracting with ethyl acetate, combining organic phases, drying with anhydrous sodium sulfate, concentrating to obtain concentrated solution, adding silica gel into the concentrated solution, mixing the mixture with the silica gel, drying the mixed silica gel at 30-40 ℃, performing elution chromatography by using a silica gel column, collecting column chromatography liquid, concentrating the mixture at 40-45 ℃ until the mixture is dried to obtain an extract, further purifying the obtained extract by using a high performance liquid chromatography, collecting eluent according to an ultraviolet detection result, and performing reduced pressure concentration to obtain the chlorogenic acid derivative.

Compared with the prior art, the invention has the beneficial effects that:

the invention adopts natural plant extract chlorogenic acid to modify the structure of the chlorogenic acid to obtain a chlorogenic acid derivative with amido bond; experiments prove that the compound has a certain anti-rot effect on mangos, so that the mangos can keep good freshness, meanwhile, pathogenic bacteria in fruits can be well inhibited and killed, and the fresh-keeping effect of the fruits is obviously improved; the preparation method is simple and convenient to operate, and can be widely used for fruit fresh keeping in fruit markets, factories and families.

Drawings

FIG. 1: the nuclear magnetic resonance hydrogen spectrum of the chlorogenic acid derivative used as the preservative in example 1.

Detailed Description

The present invention will be described in further detail with reference to specific embodiments for the purpose of making the objects, technical solutions and advantages of the present invention more apparent, but it should not be construed that the scope of the above-described subject matter of the present invention is limited to the following examples.

Example 1

Under the protection of inert gas, 20g of chlorogenic acid is dissolved in 100mL of methanol in an anhydrous reaction vessel, 10.5g of 3-amino-5-methylisoxazole is added, sodium hydroxide is added as a catalyst, the mixture is stirred for 30min, the temperature is raised to 80 ℃, the mixture is stirred and reacted for 15h, the TLC detection reaction is complete, adding saturated saline solution into the reaction solution, washing, extracting with ethyl acetate, combining organic phases, drying with anhydrous sodium sulfate, concentrating to obtain concentrated solution, adding silica gel into the concentrated solution, mixing the mixture with the silica gel, drying the mixed silica gel at 30-40 ℃, performing elution chromatography by using a silica gel column, collecting column chromatography liquid, concentrating the mixture at 40-45 ℃ until the mixture is dried to obtain an extract, further purifying the obtained extract by using a high performance liquid chromatography, collecting eluent according to an ultraviolet detection result, and performing reduced pressure concentration to obtain the chlorogenic acid derivative. The yield was 80.41%.

And (3) nuclear magnetic resonance hydrogen spectrum detection:

the sample was placed in a sample tube, and 0.5ml of DCL3 (deuterated chloroform) was injected into the sample tube with a syringe to dissolve the sample sufficiently. The sample and the reagent are required to be fully mixed, the solution is clear and transparent, and has no suspended matters or other impurities, and a nuclear magnetic resonance hydrogen spectrogram is obtained through nuclear magnetic resonance identification, and the result is shown in figure 1.

EXAMPLE 2 determination of the fruit-preserving ability of the Compounds of the invention

Fruits exposed to air for a long time are easily corroded by microorganisms, so that rotten spots are generated on the surfaces of the fruits, and the fruits are completely rotten. Fruits are soaked in the preservative solution and then dried in the sun, so that a layer of preservative protective film can be formed on the surfaces of the fruits to prevent the propagation of spoilage microorganisms. Thus, the ability of the compounds of the present invention to prevent spoilage of fruit was determined by this method.

The chlorogenic acid derivative, the chlorogenic acid and the sodium methyl p-hydroxybenzoate are prepared into 1L of aqueous solutions with the concentrations of 0mg/L, 400 mg/L, 600 mg/L, 800 mg/L and 1000mg/L respectively. Cleaning the intact mango, wiping off water, and placing in a ventilating manner at room temperature. Placing fructus Mangifera Indicae in chlorogenic acid derivatives, chlorogenic acid and sodium water solution of methyl p-hydroxybenzoate with different concentrations, soaking for 10min, taking out, and air drying at room temperature. Putting mango into a polyethylene bag, and placing the bag at room temperature without sealing. Good fruit rates (good fruit rate: number of fruits without rotting spots/number of fruits in the group) were observed and calculated every 5 days for a test period of 30 days, and the test results are shown in table 1.

TABLE 1 Effect of the Compounds of the invention on good fruit percentage in mango

The data in the table 1 show that the three drugs, namely chlorogenic acid, chlorogenic acid derivatives and methyl p-hydroxybenzoate, can prevent mango decay under different concentrations, wherein the drug concentration of the chlorogenic acid derivatives has a preservative effect already at 400 mug/mL, the corresponding good fruit rate is 28.09%, and the good fruit rates of the other two drugs under the same concentration are 0%; when the concentration of the medicines reaches 1000 mug/mL, the three medicines have better preservative effect, wherein the preservative effect of the chlorogenic acid derivative is the best, and the corresponding good fruit rate is 80.72%. Therefore, the fruit preservative can be well used as a fruit preservative.

EXAMPLE 3 inhibitory Effect of the Compounds of the present invention on pathogenic bacteria

Seven-eight mature mangoes are selected, the sizes of the mangoes are almost consistent, and the mangoes have no damage, no speckles and no plant diseases and insect pests on the surface. Cleaning all mangos, soaking in hot water at 50 ℃ for about 10 minutes, taking out and drying in the sun for later use. The experimental group selects the chlorogenic acid derivative; carbendazim was used as control group 1; thiophanate methyl is control 2; respectively, the common rot-causing fungi in the storage period of mango: mango anthracnose and mango stem rot pathogen are used as test strains to perform bacteriostasis experiments, and the results are shown in table 2.

TABLE 2 inhibitory Effect of the Compounds of the present invention on pathogenic bacteria

The data in table 2 show that the experimental group and the control group have good inhibitory activity on common pathogenic fungi in the storage period of fruits, wherein the chlorogenic acid derivative in the experimental group shows better bacteriostatic effect, which indicates that the chlorogenic acid derivative can well inhibit and kill various pathogenic bacteria and improve the fresh-keeping effect of fruits.