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CN-122010816-A - Melanin acetylation derivative, its preparation method and application

CN122010816ACN 122010816 ACN122010816 ACN 122010816ACN-122010816-A

Abstract

The application relates to the technical field of bio-based functional materials, in particular to a melanin acetylation derivative, a preparation method and application thereof. According to the application, a single compound (melanin acetyl derivative) with a definite structure is obtained by acetylating a specific melanin monomer intermediate, instead of a mixture, the problem of uncertain natural melanin structure is solved, the stability and the processability are better, and the quality control and the standardized application are facilitated, wherein the melanin acetyl derivative retains the conjugated structure and the phenolic hydroxyl of a melanin core, and has good ultraviolet absorption and antioxidant activity. The preparation method of the melanin acetylation derivative provided by the application has the advantages of mild conditions, no need of high temperature and high pressure, simple post-treatment and suitability for large-scale production.

Inventors

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Assignees

  • 南京合谷生命生物科技有限公司

Dates

Publication Date
20260512
Application Date
20260414

Claims (10)

  1. 1. The melanin acetyl derivative is characterized by having a structural formula shown in a formula (I); Formula (I).
  2. 2. A method for producing an acetylated derivative of melanin according to claim 1, comprising the steps of: S1, dissolving 4- [5- (2, 2-diaminoethyl) -2, 3-dihydroxyphenyl ] -1H-indole-5, 6-diphenol in water, and controlling the temperature for reaction to obtain a solution; s2, dropwise adding an acetylation reagent into the solution in the step S1, and heating to perform an acetylation reaction after the dropwise adding is finished to obtain a reaction product solution; and S3, adding ice water into the reaction product solution obtained in the step S2, cooling, stirring, separating out a product, performing solid-liquid separation, and drying a filter cake to obtain the melanin acetylated derivative.
  3. 3. The method for preparing an acetylated derivative of melanin according to claim 2, wherein ice water is used in the step S1 to control the temperature to 0-5 ℃.
  4. 4. The method for producing an acetylated melanin derivative according to claim 2, wherein in step S2, the molar ratio of 4- [5- (2, 2-diaminoethyl) -2, 3-dihydroxyphenyl ] -1H-indole-5, 6-diol and the acetylating agent in step S1 is 1 (0.8 to 2.0).
  5. 5. The method for producing an acetylated derivative of melanin according to claim 2, wherein the acetylating agent comprises acetic anhydride or acetyl chloride.
  6. 6. The method for producing an acetylated derivative of melanin according to claim 2, wherein the temperature for the acetylation reaction in step S2 is 15 to 40 ℃ and the reaction time is 2 to 12 hours.
  7. 7. The method for producing an acetylated melanin derivative according to claim 2, wherein the solution of the acetylation reaction in step S2 has a pH of 6 to 8, and the pH is controlled by adjusting at least one of potassium carbonate, sodium hydroxide, potassium hydroxide and sodium bicarbonate.
  8. 8. The method for preparing an acetylated derivative of melanin according to claim 2, wherein in step S3, the temperature is controlled to be 0-5 ℃.
  9. 9. The method for producing an acetylated melanin derivative according to claim 2, wherein in step S3, the mass ratio of ice water to the reaction product solution is (2 to 5): 1.
  10. 10. Use of a melanin-acetylated derivative of claim 1 in fabric dyeing.

Description

Melanin acetylation derivative, its preparation method and application Technical Field The application relates to the technical field of bio-based functional materials, in particular to a melanin acetylation derivative, a preparation method and application thereof. Background Melanin is a natural pigment widely existing in living bodies and has excellent ultraviolet absorption, antioxidation and free radical scavenging ability. Natural melanin (e.g., eumelanin) is typically a highly crosslinked amorphous polymer formed from monomers such as 5, 6-Dihydroxyindole (DHI) and its carboxylic acid Derivatives (DHICA) by complex oxidative polymerization. The complex polymeric structure gives melanin a plurality of functions, but also causes the problems of poor solubility, difficult precise control of the structure, large batch variability and the like, and greatly limits the application of the polymer in the high-end field. In order to improve the solubility and processability of melanin, the prior art generally attempts to chemically modify it. Acetylation is a common modification means, which can shield hydrophilic groups such as phenolic hydroxyl groups and amino groups in melanin molecules, and increase the hydrophobicity of the melanin molecules, so that the solubility of the melanin molecules in water can be improved, and the color fastness of subsequent dyeing is facilitated. However, direct acetylation modification of a high molecular weight melanin polymer often has problems such as uneven reaction, difficulty in controlling the modification degree, and ambiguous product structure. Therefore, there is an urgent need in the art to develop a melanin acetylation derivative which has a definite structure, is controllable in solubility, and is easy to mass-produce, and a preparation method thereof. Disclosure of Invention The application aims to overcome the defects of the prior art and provide a melanin acetylation derivative, a preparation method and application thereof. The melanin acetylation derivative provided by the application has better stability and processability. In order to achieve the above purpose, the technical scheme adopted by the application is as follows: The application provides a melanin acetylation derivative, the structural formula of which is shown as a formula (I), wherein the melanin acetylation derivative is named as N- [1- (acetylamino) -2- [5- (5, 6-dihydroxyl-1H-indol-4-yl) -3, 4-dihydroxyl phenyl ] ethyl ] acetamide. Formula (I). According to the application, a single compound (melanin acetyl derivative) with a definite structure is obtained by acetylating a specific melanin monomer intermediate, but not a mixture, so that the problem of uncertain natural melanin structure is solved, and the method has better stability and processability, and is beneficial to quality control and standardized application. Wherein, the melanin acetylation derivative maintains the conjugated structure and phenolic hydroxyl of the melanin core, and has good ultraviolet absorption and antioxidant activity. As a preferred embodiment of the method for producing an acetylated derivative of melanin according to the present application, the method comprises the steps of: S1, dissolving 4- [5- (2, 2-diaminoethyl) -2, 3-dihydroxyphenyl ] -1H-indole-5, 6-diphenol in water, and controlling the temperature for reaction to obtain a solution; s2, dropwise adding an acetylation reagent into the solution in the step S1, and heating to perform an acetylation reaction after the dropwise adding is finished to obtain a reaction product solution; and S3, adding ice water into the reaction product solution obtained in the step S2, cooling, stirring, separating out a product, performing solid-liquid separation, and drying a filter cake to obtain the melanin acetylated derivative. The reaction formula for preparing the melanin acetyl derivative is as follows: According to the application, phenyl indole is used as a raw material, a melanin acetylated derivative with a definite structure can be efficiently synthesized, and the obtained melanin acetylated derivative has better stability and processability. The preparation method has the advantages of mild condition, simple operation, high yield and easy industrialized production. In a preferred embodiment of the method for preparing the melanin acetylated derivative of the present application, ice water is used to control the temperature in step S1 to 0-5 ℃. The ice water bath in the range controls the temperature, and can avoid the oxidative polymerization reaction caused by overhigh temperature. In the preferred embodiment of the method for producing an acetylated derivative of melanin of the present application, in the step S2, the molar ratio of 4- [5- (2, 2-diaminoethyl) -2, 3-dihydroxyphenyl ] -1H-indole-5, 6-diol and the acetylating agent in the step S1 is 1 (0.8 to 2.0). Preferably, the molar ratio of the 4- [5- (2, 2-diaminoethyl) -2, 3-dihydroxyphenyl ] -1H-indole-