CN106916085A - Modified curcumin - Google Patents

Abstract

The invention discloses modified curcumin, which has a structure shown in the following chemical formula 1 (chemical formula 1)In chemical formula 1, R¹Is composed ofn is an integer of 1 to 20, R²Is hydrogen orR³Is hydrogen or methyl.

Description

Modified Curcumin

technical field

The invention relates to a curcumin, in particular to a modified curcumin with good reactivity with other monomers containing carbon-carbon double bonds.

Background technique

Curcumin is a natural yellow pigment, which has been widely used as a food coloring agent and dye because of its good coloring effect and not easy to fade.

In order to improve the applicability of curcumin, such as improving the reactivity between curcumin and other substances with carbon-carbon double bonds, if the structural ends of curcumin can have reactive functional groups, it is bound to improve the interaction between curcumin and other substances. The binding stability between them makes curcumin applicable to various related fields that require dyeing.

Contents of the invention

To achieve the above-disclosed purpose, the present invention provides a modified curcumin, which has a carbon-carbon double bond (C=C) structure at its structural end, so it can be stably combined with other compounds with carbon-carbon double bonds.

The modified curcumin provided by the present invention has a structure shown in the following chemical formula 1:

[chemical formula 1]

In chemical formula 1, R ¹ is n is an integer from ¹ to 20, R2 is hydrogen or ^R3 is hydrogen or methyl.

Wherein, the modified curcumin is obtained by reacting curcumin and isocyanoalkyl (meth)acrylate monomers.

Wherein, the modified curcumin is obtained by reacting curcumin, a catalyst and an isocyanoalkyl (meth)acrylate monomer.

Among them, the alkyl groups in the isocyanoalkyl (meth)acrylate monomers used for the reaction are methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, Nonyl, Decyl, Undecyl, Dodecyl, Tridecyl, Tetradecyl, Pentadecyl, Hexadecyl, Heptadecyl, Octadecyl, Nonadecyl or eicosyl.

Wherein, the isocyanoalkyl (meth)acrylate monomer used for the reaction is isocyanoethyl methacrylate or isocyanoethyl acrylate.

Wherein, the catalyst used for the reaction may be an amine catalyst or a metal catalyst.

Wherein, the catalyst used for the reaction is 1,4-diazabicyclo[2.2.2]octane.

Since the structural end (unilateral or bilateral) of the modified curcumin of the present invention has carbon-carbon double bonds, it can have good reactivity with other substances that also have carbon-carbon double bonds, thereby improving the relationship between curcumin and other substances. The excellent binding stability enables curcumin to be widely used in various related fields that require dyeing.

Description of drawings

Fig. 1 is the chromatogram of the modified curcumin that preparation example 1 makes.

Fig. 2 is the chromatogram of the modified curcumin that preparation example 2 makes.

Fig. 3 is the chromatogram of unmodified curcumin.

detailed description

The invention provides a modified curcumin, which has a structure shown in the following chemical formula 1:

[chemical formula 1]

In chemical formula 1 disclosed above, R ¹ is n is an integer from ¹ to 20, R2 is hydrogen or ^R3 is hydrogen or methyl.

According to an embodiment of the present invention, the modified curcumin of the present invention can be prepared by the following preparation method:

(A) mix curcumin, catalyst and solvent and heat, make curcumin fully dissolve and form a first mixture;

(B) slowly adding a second mixture comprising a monomer having a reactive functional group and a solvent to the first mixture of step (A) and heating to the reaction temperature to form a reactant; and

(C) After the reactant in step (B) is cooled to room temperature, the procedures of solvent removal, extraction and recrystallization are sequentially performed to obtain modified curcumin.

It should be noted that the catalyst in the step (A) of the preparation method of the foregoing embodiment is only used to accelerate the reaction rate, therefore, the catalyst can be selectively used or not used.

The "catalyst" in the step (A) of the aforementioned preparation method is used to activate the hydroxyl group (OH) of the curcumin structure, which can be an amine catalyst or a metal catalyst. Examples of amine catalysts are (but not limited to) 1,4-diazabicyclo[2.2.2]octane, triethylamine, tetramethylethylenediamine, 2,2-dimorpholinodiethyl ethers; examples of metal catalysts are, but are not limited to, dibutyltin dilaurate, dioctyltin dilaurate, stannous octoate, dibutyltin diacetate, zinc acetylacetonate, bismuth carboxylate, bismuth isooctanoate, zinc isooctanoate, methyl Bismuth sulfonate, zinc naphthenate, tetrabutyl titanate, cobalt octoate, iron octoate, lead octoate, potassium octoate. In one embodiment of the present invention, 1,4-diazabicyclo[2.2.2]octane is used.

The heating temperature in step (A) of the aforementioned preparation method is a temperature capable of fully dissolving curcumin, which may be 50°C to 55°C, and is 50°C in an embodiment of the present invention.

The "solvent" described in the steps (A) and (B) of the aforementioned preparation method is an anhydrous organic solvent for dissolving curcumin and monomers with reactive functional groups, which can be (but not limited to) anhydrous THF ( THF), anhydrous dimethylsulfoxide (DMSO), anhydrous dimethylformamide (DMF), anhydrous dimethylacetamide (DMAC), anhydrous dichloromethane (dichloromethane), anhydrous chloroform (chloroform ), anhydrous acetonitrile (acetonitrile), and combinations of the foregoing. Anhydrous THF was used in one embodiment of the present invention.

The "monomer with a reactive functional group" described in step (B) of the aforementioned preparation method is a monomer with a carbon-carbon double bond structure, preferably (but not limited to) (meth)acrylic acid with an NCO functional group Isocyanoalkyl ester monomers.

The alkyl group in the aforementioned "isocyanoalkyl (meth)acrylate monomer" may include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl or eicosane base, as contained in the specification of Chinese patent CN103450243B. In one embodiment of the present invention, 2-isocyanatoethylmethacrylate is used.

It should be noted that the "isocyanoalkyl (meth)acrylate monomer" mentioned in this article refers to the "isocyanoalkyl methacrylate monomer" and the "isocyanoalkyl acrylate monomer". base ester monomers".

The heating temperature in step (B) of the aforementioned preparation method is a temperature capable of reacting curcumin with monomers having reactive functional groups, which may be 70°C to 75°C, and is 70°C in one embodiment of the present invention.

The extraction in step (C) of the aforementioned preparation method can be accomplished using ethyl acetate and water; the recrystallization can be accomplished using acetone and n-hexane.

In the aforementioned preparation method, the molar ratio of curcumin to monomers with reactive functional groups ranges from 1:1.1 to 1:2.2.

Hereinafter, the content of the present invention will be described in more detail through specific examples. However, these examples are only used to illustrate the present invention and not to limit the scope of the present invention.

The reaction formula for preparing modified curcumin is as follows:

Before illustrating the embodiment, what the applicant wants to state earlier is that because curcumin itself has a functional group (OH group) that can react at both ends, it is shown that when curcumin only has a unilateral OH group The structure of modified curcumin obtained when the reaction is carried out, and the structure of modified curcumin obtained when both OH groups of curcumin are reacted.

Preparation Example 1

Under a nitrogen atmosphere, add 1 g of curcumin and 0.01 g of 1,4-diazabicyclo[2.2.2] octane into a round bottom bottle, then add 30 mL of anhydrous tetrahydrofuran (THF), and heat to 50 ℃ and maintained for 30 minutes to fully dissolve the curcumin and the catalyst. Thereafter, a mixture of 0.84 mL of isocyanoethyl methacrylate and 20 mL of anhydrous tetrahydrofuran was slowly dropped into the round bottom bottle, and then the temperature was raised to 70° C. for 24 hours to react. After the reaction is completed, the temperature is lowered to room temperature, the tetrahydrofuran is removed using a vacuum concentrator, and then ethyl acetate and water are used for extraction, and finally, acetone and n-hexane are used for recrystallization to finally obtain modified curcumin.

The chromatogram of the modified curcumin prepared in Preparation Example 1 (detected by high-performance liquid chromatography, model HPLC1260, sold by Agilent Technologies) is shown in Figure 1 .

In addition, the ¹ H-NMR analysis results of the modified curcumin of Preparation Example 1 are as follows:

¹ H-NMR (400MHz, CDCl ₃ ): δ2.00(s,6H),3.61-3.65(q,4H),3.91(s,6H),4.32-4.35(t,4H),5.43-5.45(t ,2H),5.65(s,2H),5.87(s,1H),6.18(s,2H),6.56-6.60(d,2H),7.13-7.20(m,6H),7.62-7.65(d,2H ).

Compared with the chromatogram (Fig. 3) of Fig. 1 and unmodified curcumin, and the analytical results of the above ¹ H-NMR, it can be confirmed that the modified curcumin obtained in Preparation Example 1 has carbon carbon at the end of its bilateral structure. double bond.

Preparation example 2

The modified curcumin was prepared roughly in the same manner as in Preparation Example 1, except that the amount of isocyanoethyl methacrylate was changed to 0.42 mL, and the rest of the steps were the same as in Preparation Example 1 to obtain modified curcumin.

The chromatogram of the modified curcumin prepared in Preparation Example 2 (detected by high-performance liquid chromatography, model HPLC1260, sold by Agilent Technologies) is shown in Figure 2 .

Compared with the chromatogram (Fig. 3) of Fig. 2 and the chromatogram (Fig. 3) of unmodified curcumin and the modified curcumin (Fig. 1) that the bilateral structure end of Preparation Example 1 has carbon-carbon double bond, it can be confirmed that the preparation The modified curcumin obtained in Example 2 contains unmodified curcumin, modified curcumin with carbon-carbon double bonds at the end of the unilateral structure, and modified curcumin with carbon-carbon double bonds at the end of the bilateral structure.

In addition, when the isocyanoalkyl (meth)acrylate monomer is replaced by isocyanoethyl methacrylate with other isocyanoalkyl (meth)acrylate monomers with carbon numbers from 1 to 20 When the body (that is, the alkyl group is methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl base, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group or eicosyl group), the modified curcuma longa of structure shown in chemical formula 1 can also be obtained white. As shown in the example below.

Preparation example 3

Prepare modified curcumin in the same manner as Preparation Example 1, except that isocyanatoethyl methacrylate is replaced with isocyanatoethyl acrylate, and the amount used is 0.76mL, and the rest of the steps are the same as Preparation Example 1. To obtain modified curcumin.

The ¹ H-NMR analytical results of the modified curcumin obtained by Preparation Example 3 are as follows:

¹ H-NMR (400MHz, CDCl ₃ ): δ3.59-3.60(q,4H),3.89(s,6H),4.31-4.34(t,4H),5.44-5.47(t,2H),5.85(s ,1H),5.88-5.91(dd,2H),6.13-6.20(dd,2H),6.44-6.49(dd,2H),6.53-5.58(d,2H),7.11-7.18(m,6H),7.59 -7.63(d,2H).

From the above analysis results, it can be seen that the modified curcumin shown in Chemical Formula 1 can also be obtained by using isocyanoethyl acrylate.

It can be confirmed from the above preparation examples that both the isocyanoalkyl methacrylate monomer and the isocyanoalkyl acrylate monomer can be used to prepare the modified curcumin of the present invention.

Since the structural end (unilateral or bilateral) of the modified curcumin of the present invention has carbon-carbon double bonds, it can have good reactivity with other substances that also have carbon-carbon double bonds, thereby improving the relationship between curcumin and other substances. The excellent binding stability enables curcumin to be widely used in various related fields that require dyeing. The aforementioned other substances with carbon-carbon double bonds such as (but not limited to) ethylene glycol dimethacrylate (EGDMA), methacrylic acid (methacrylic acid, MA), methyl methacrylate (methyl methacrylate, MMA), 2-hydroxyethyl methacrylate (2-hydroxyethyl methacrylate, HEMA), N-vinyl-2-pyrrolidone (N-vinyl-2-pyrrolidone, NVP), etc.

Certainly, the present invention also can have other various embodiments, without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and deformations according to the present invention, but these corresponding changes All changes and modifications should belong to the protection scope of the claims of the present invention.

Claims (7)

1. A modified curcumin has a structure shown in the following chemical formula 1: [chemical formula 1] In chemical formula 1, R ₁ is n is an integer from ₁ to 20, R2 is hydrogen or _R3 is hydrogen or methyl. 2. The modified curcumin according to claim 1, characterized in that, the modified curcumin is obtained by reacting curcumin and isocyanoalkyl (meth)acrylate monomers. 3. modified curcumin according to claim 1, is characterized in that, described modified curcumin is obtained by reacting curcumin, catalyzer and (meth)acrylic acid isocyano alkyl ester monomer. 4. according to claim 2 or 3 described modified curcumin, it is characterized in that, the alkyl system in the (meth)acrylic acid isocyanoalkyl esters monomer for carrying out reaction is methyl, ethyl , Propyl, Butyl, Pentyl, Hexyl, Heptyl, Octyl, Nonyl, Decyl, Undecyl, Dodecyl, Tridecyl, Tetradecyl, Pentadecyl, Decyl Hexadecyl, Heptadecyl, Octadecyl, Nonadecyl or Eicosyl. 5. modified curcumin according to claim 4, is characterized in that, the (meth)acrylic acid isocyanoalkyl ester monomer for reacting is isocyanoethyl methacrylate or acrylic acid isocyanate ethyl ethyl ester. 6. modified curcumin according to claim 3, is characterized in that, the catalyst for carrying out reaction can be amine catalyst or metal catalyst. 7. The modified curcumin according to claim 6, characterized in that the catalyst for the reaction is 1,4-diazabicyclo[2.2.2]octane.