A kind of acrylic ester pyrrole compound and preparation method thereof

Abstract

The present invention belongs to the field of organic synthesis, and in particular, relates to an acrylate pyrrole compound and a preparation method thereof. The acrylate pyrrole compound provided by the present invention has a structure of formula (I), and the compound is prepared according to the following steps: a) in the presence of a catalyst and a protective gas, the monomer of formula (i) reacts with an alkaline reagent to obtain a compound of formula (ii); b) in the presence of a catalyst and a protective gas, the compound of formula (ii) reacts with a halogenated alcohol to obtain a compound of formula (iii); c) in the presence of a dehydrating agent, a catalyst and a protective gas, the compound of formula (iii) reacts with a compound of formula (iv) to obtain an acrylate pyrrole compound of formula (I). The technical solution of the present invention provides a new idea for broadening the chemical structure and synthesis methodology of acrylate compounds, and has a wide range of application scenarios.

Description

Technical Field

[0001] The invention belongs to the field of organic synthesis, and in particular relates to an acrylic ester pyrrole compound and a preparation method thereof. Background Art

[0002] Acrylates are a type of chemical additive product with a very wide range of applications. This type of product has good transparency, toughness, thermal stability and good chemical stability. Multifunctional acrylates, as one of them, occupy a very important position in this field. By introducing special functional groups, acrylate products have a wide range of application scenarios. If the molecule contains multiple unsaturated olefin groups that can be used for polymerization reactions, it can be used in rubber, plastic, photocurable coatings and other application fields. The diversity and designability of its structure determine its huge application scenarios. Therefore, the design and development of new acrylate monomers has always been one of the research hotspots in the field of organic synthesis. Summary of the invention

[0003] In view of this, one of the objects of the present invention is to design an acrylic ester pyrrole compound with a completely new structure, which has a unique "double-arm" structure; the second object of the present invention is to provide a method for preparing the acrylic ester pyrrole compound, which has high reaction efficiency and excellent economic efficiency, and provides a new idea for broadening the synthetic methodology of acrylic ester compounds.

[0004] The present invention provides an acrylic ester pyrrole compound, the chemical structure of which is shown in formula (I):

[0005]

[0006] In formula (I), R1, R2, R3 and R4 are independently selected from -H or a C1-C4 alkyl group.

[0007] Preferably, R1, R2, R3 and R4 are independently selected from -H or -CH3.

[0008] The present invention provides a method for preparing an acrylic acid ester pyrrole compound, comprising the following steps:

[0009] a) reacting a formaldehyde pyrrole monomer of formula (i) with an alkali reagent in the presence of a catalyst and a protective gas to obtain a methanol pyrrole compound of formula (ii);

[0010] b) reacting the methanol pyrrole compound with a halogenated alcohol in the presence of a catalyst and a protective gas to obtain a hydroxyl-containing pyrrole compound of formula (iii);

[0011] c) reacting the hydroxyl-containing pyrrole compound with the acrylic compound of formula (iv) in the presence of a dehydrating agent, a catalyst and a protective gas to obtain an acrylic ester pyrrole compound of formula (I);

[0012]

[0013] Wherein, R1, R2, R3 and R4 are independently selected from -H or C1-C4 alkyl.

[0014] Preferably, in step a), the alkaline agent is sodium hydroxide and / or potassium hydroxide; and the molar ratio of the formaldehyde pyrrole monomer to the alkaline agent is 1:(1-1.4).

[0015] Preferably, in step a), the catalyst is cobalt tetraoxide; and the molar ratio of the formaldehyde pyrrole monomer to the catalyst is 1:(0.01-0.03).

[0016] Preferably, in step a), the reaction is carried out in a solvent; the solvent is isopropanol and / or isobutanol.

[0017] Preferably, in step a), the reaction temperature is 40-60°C.

[0018] Preferably, in step a), the reaction time is 0.5 to 1 h.

[0019] Preferably, in step b), the halogenated alcohol is 2-bromoethanol and / or 2-chloroethanol; and the molar ratio of the methanol pyrrole compound to the halogenated alcohol is 1:(1-1.4).

[0020] Preferably, in step b), the catalyst is one or more of sodium hydroxide, potassium hydroxide, sodium hydride and potassium hydride; and the molar ratio of the methanol pyrrole compound to the catalyst is 1:(4-5).

[0021] Preferably, in step b), the reaction is carried out in a solvent; the solvent is one or more of acetonitrile, dimethyl sulfoxide, N,N-dimethylformamide and N,N-dimethylacetamide.

[0022] Preferably, in step b), the reaction temperature is 10-40°C.

[0023] Preferably, in step b), the reaction time is 10 to 20 hours.

[0024] Preferably, in step c), the molar ratio of the hydroxyl pyrrole compound to the acrylic compound is 1:(2-2.4).

[0025] Preferably, in step c), the dehydrating agent is 1,3-dicyclohexylcarbodiimide; and the molar ratio of the hydroxyl pyrrole compound to the dehydrating agent is 1:(2-3).

[0026] Preferably, in step c), the catalyst is 4-dimethylaminopyridine; and the molar ratio of the hydroxyl-containing pyrrole compound to the catalyst is 1:(0.2-0.3).

[0027] Preferably, in step c), the reaction is carried out in a solvent; the solvent is one or more of acetonitrile, dimethyl sulfoxide, N,N-dimethylformamide and N,N-dimethylacetamide.

[0028] Preferably, in step c), the reaction temperature is 10-40°C.

[0029] Preferably, in step c), the reaction time is 3 to 8 hours.

[0030] Compared with the prior art, the present invention provides an acrylate pyrrole compound and a preparation method thereof. The acrylate pyrrole compound provided by the present invention has a structure of formula (I), wherein R1, R2, R3 and R4 are independently selected from -H or C1-C4 alkyl. The acrylate pyrrole compound provided by the present invention is a novel acrylate pyrrole compound with a unique "double-arm" structure, which enriches the structural diversity of acrylate monomers. The preparation method provided by the present invention comprises the following steps: a) in the presence of a catalyst and a protective gas, a formaldehyde-based pyrrole monomer of a structure of formula (i) reacts with an alkaline reagent to obtain a methanol-based pyrrole compound of a structure of formula (ii); b) in the presence of a catalyst and a protective gas, the methanol-based pyrrole compound reacts with a halogenated alcohol to obtain a hydroxyl-containing pyrrole compound of a structure of formula (iii); c) in the presence of a dehydrating agent, a catalyst and a protective gas, the hydroxyl-containing pyrrole compound reacts with an acrylic acid compound of a structure of formula (iv) to obtain an acrylic acid ester pyrrole compound of a structure of formula (I); wherein R1, R2, R3 and R4 independently select -H or an alkyl group of C1 to C4. The method provided by the present invention uses a formaldehyde-based pyrrole monomer as a starting material, and finally prepares a pyrrole derivative containing an acrylic acid ester functional group by designing a reasonable synthetic route; the method is a newly designed reaction path, which provides a new idea for broadening the synthetic methodology of acrylic acid ester compounds; and the raw materials used in the method are low in cost, widely available, highly efficient in reaction, and significantly increase the added value of the product, and has a wide range of application scenarios. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] The present invention provides an acrylic ester pyrrole compound, the chemical structure of which is shown in formula (I):

[0033]

[0034] In formula (I), R1, R2, R3 and R4 are independently selected from -H or a C1-C4 alkyl group; the alkyl group may specifically be a methyl group, an ethyl group, a propyl group or a butyl group, and a methyl group is most preferred.

[0035] The acrylate pyrrole compound provided by the present invention is a novel acrylate pyrrole compound with a unique "double-arm" structure, which enriches the structural diversity of acrylate monomers.

[0036] The present invention also provides a method for preparing an acrylic acid ester pyrrole compound, comprising the following steps:

[0037] a) reacting a formaldehyde pyrrole monomer of formula (i) with an alkali reagent in the presence of a catalyst and a protective gas to obtain a methanol pyrrole compound of formula (ii);

[0038] b) reacting the methanol pyrrole compound with a halogenated alcohol in the presence of a catalyst and a protective gas to obtain a hydroxyl-containing pyrrole compound of formula (iii);

[0039] c) reacting the hydroxyl-containing pyrrole compound with the acrylic compound of formula (iv) in the presence of a dehydrating agent, a catalyst and a protective gas to obtain an acrylic ester pyrrole compound of formula (I);

[0040]

[0041] Wherein, R1, R2, R3 and R4 are independently selected from -H or C1-C4 alkyl; the alkyl group can be specifically methyl, ethyl, propyl or butyl, and the most preferred is methyl.

[0042] In the preparation method provided by the present invention, the reaction equation involved in step a) is as follows:

[0043]

[0044] Wherein, R1, R2 and R3 are independently selected from -H or C1-C4 alkyl, and the alkyl is preferably methyl.

[0045] In the preparation method provided by the present invention, in step a), the alkaline agent is preferably sodium hydroxide and / or potassium hydroxide; the molar ratio of the formaldehyde pyrrole monomer to the alkaline agent is preferably 1:(1-1.4), specifically 1:1, 1:1.02, 1:1.05, 1:1.07, 1:1.1, 1:1.12, 1:1.15, 1:1.17, 1:1.2, 1:1.23, 1:1.25, 1:1.27, 1:1.3, 1:1.32, 1:1.35, 1:1.37 or 1:1.4.

[0046] In the preparation method provided by the present invention, in step a), the catalyst is preferably cobalt tetraoxide; the molar ratio of the formaldehyde pyrrole monomer to the catalyst is preferably 1:(0.01-0.03), specifically 1:0.01, 1:0.012, 1:0.015, 1:0.017, 1:0.02, 1:0.023, 1:0.025, 1:0.027 or 1:0.03.

[0047] In the preparation method provided by the present invention, in step a), the protective gas includes but is not limited to nitrogen and / or rare gases, preferably nitrogen and / or argon, and more preferably argon.

[0048] In the preparation method provided by the present invention, in step a), the reaction is carried out in a solvent; the solvent is preferably isopropanol and / or isobutanol.

[0049] In the preparation method provided by the present invention, in step a), the reaction temperature is preferably 40-60°C, more preferably 45-55°C, specifically 45°C, 46°C, 47°C, 48°C, 49°C, 50°C, 51°C, 52°C, 53°C, 54°C or 55°C; the reaction time is preferably 0.5-1h, specifically 0.5h, 0.6h, 0.7h, 0.8h, 0.9h or 1h. In the present invention, the reaction degree is preferably monitored by thin layer chromatography to determine the reaction endpoint time.

[0050] In the preparation method provided by the present invention, the specific operation process of step a) preferably includes: adding formaldehyde pyrrole monomer, alkaline reagent and catalyst to the solvent under a protective gas atmosphere, stirring and mixing and heating to the reaction temperature; after reacting for a period of time, monitoring the degree of reaction by thin layer chromatography to determine the end time of the reaction; after the reaction is completed, the product is post-treated to obtain a methanol pyrrole compound. Wherein, the stirring method is preferably magnetic stirring; the thin layer chromatography monitoring is preferably carried out after the reaction is carried out for 0.5h; the post-treatment method is preferably: first adding deionized water and ethyl acetate, extracting and taking the organic phase, then rotary evaporating to remove the solvent, and then using petroleum ether and ethyl acetate as eluents to separate the product by column chromatography.

[0051] In the preparation method provided by the present invention, the reaction equation involved in step b) is as follows:

[0052]

[0053] Wherein, R1, R2 and R3 are independently selected from -H or C1-C4 alkyl, and the alkyl is preferably methyl; X is halogen, preferably Br or Cl.

[0054] In the preparation method provided by the present invention, in step b), the halogenated alcohol is preferably 2-bromoethanol and / or 2-chloroethanol, more preferably 2-bromoethanol; the molar ratio of the methanol-based pyrrole compound to the halogenated alcohol is preferably 1:(1-1.4), specifically 1:1, 1:1.02, 1:1.05, 1:1.07, 1:1.1, 1:1.12, 1:1.15, 1:1.17, 1:1.2, 1:1.23, 1:1.25, 1:1.27, 1:1.3, 1:1.32, 1:1.35, 1:1.37, 1:1.4.

[0055] In the preparation method provided by the present invention, in step b), the catalyst is preferably one or more of sodium hydroxide, potassium hydroxide, sodium hydride and potassium hydride, more preferably potassium hydride; the molar ratio of the methanol pyrrole compound to the catalyst is preferably 1:(4-5), specifically 1:4, 1:4.1, 1:4.2, 1:4.3, 1:4.4, 1:4.5, 1:4.6, 1:4.7, 1:4.8, 1:4.9 or 1:5.

[0056] In the preparation method provided by the present invention, in step b), the protective gas includes but is not limited to nitrogen and / or rare gas, preferably nitrogen and / or argon, more preferably argon.

[0057] In the preparation method provided by the present invention, in step b), the reaction is carried out in a solvent; the solvent is preferably one or more of acetonitrile, dimethyl sulfoxide, N,N-dimethylformamide and N,N-dimethylacetamide.

[0058] In the preparation method provided by the present invention, in step b), the reaction temperature is preferably 10-40°C, more preferably 20-30°C, specifically 20°C, 21°C, 22°C, 23°C, 24°C, 25°C, 26°C, 27°C, 28°C, 29°C or 30°C; the reaction time is preferably 10-20h, more preferably 12-14h, specifically 12h, 12.3h, 12.5h, 12.7h, 13h, 13.2h, 13.5h, 13.7h or 14h. In the present invention, the reaction degree is preferably monitored by thin layer chromatography to determine the reaction endpoint time.

[0059] In the preparation method provided by the present invention, the specific operation process of step b) preferably includes: adding a methanol-based pyrrole compound to a solvent under a protective gas atmosphere, adding a catalyst for mixed activation, and dropping a halogenated alcohol into the mixed solution for reaction; after a period of reaction, monitoring the degree of reaction by thin layer chromatography to determine the end time of the reaction; after the reaction is completed, post-treating the product to obtain a hydroxyl-containing pyrrole compound. Wherein, the thin layer chromatography monitoring is preferably carried out after the reaction is carried out for 12 hours; the post-treatment method is preferably: firstly removing the solvent by reduced pressure distillation, and then using petroleum ether and ethyl acetate as eluents, and separating the product by column chromatography.

[0060] In the preparation method provided by the present invention, the reaction equation involved in step c) is as follows:

[0061]

[0062] Wherein, R1, R2, R3 and R4 are independently selected from -H or C1-C4 alkyl, and the alkyl is preferably methyl.

[0063] In the preparation method provided by the present invention, in step c), the acrylic compound is preferably acrylic acid or methacrylic acid; the molar ratio of the hydroxyl pyrrole compound to the acrylic compound is preferably 1:(2-2.4), specifically 1:2, 1:2.03, 1:2.05, 1:2.07, 1:2.1, 1:2.12, 1:2.15, 1:2.17, 1:2.2, 1:2.23, 1:2.25, 1:2.27, 1:2.3, 1:2.32, 1:2.35, 1:2.37 or 1:2.4.

[0064] In the preparation method provided by the present invention, in step c), the dehydrating agent is preferably 1,3-dicyclohexylcarbodiimide; the molar ratio of the hydroxyl pyrrole compound to the dehydrating agent is preferably 1:(2-3), specifically 1:2, 1:2.1, 1:2.2, 1:2.3, 1:2.4, 1:2.5, 1:2.6, 1:2.7, 1:2.8, 1:2.9 or 1:3.

[0065] In the preparation method provided by the present invention, in step c), the catalyst is preferably 4-dimethylaminopyridine; the molar ratio of the hydroxyl pyrrole compound to the catalyst is preferably 1:(0.2-0.3), specifically 1:0.2, 1:0.21, 1:0.22, 1:0.23, 1:0.24, 1:0.25, 1:0.26, 1:0.27, 1:0.28, 1:0.29 or 1:0.3.

[0066] In the preparation method provided by the present invention, in step c), the protective gas includes but is not limited to nitrogen and / or rare gas, preferably nitrogen and / or argon, more preferably argon.

[0067] In the preparation method provided by the present invention, in step c), the reaction is carried out in a solvent; the solvent is preferably one or more of acetonitrile, dimethyl sulfoxide, N,N-dimethylformamide and N,N-dimethylacetamide.

[0068] In the preparation method provided by the present invention, in step c), the reaction temperature is 10-40°C, preferably 20-30°C, specifically 20°C, 21°C, 22°C, 23°C, 24°C, 25°C, 26°C, 27°C, 28°C, 29°C or 30°C; the reaction time is preferably 3-8h, specifically 3h, 3.5h, 4h, 4.5h, 5h, 5.5h, 6h, 6.5h, 7h, 7.5h or 8h.

[0069] In the preparation method provided by the present invention, in step c), the temperature of the dehydrating agent and the catalyst when mixed with the hydroxyl pyrrole compound and the acrylic compound is preferably 0° C., and after the mixing is completed, the temperature is raised to the reaction temperature.

[0070] In the preparation method provided by the present invention, the specific operation process of step c) preferably includes: mixing the hydroxyl-containing pyrrole compound and the solvent under a protective gas atmosphere, starting stirring, and adding an acrylic compound; lowering the temperature of the mixed solution to 0°C, blowing and bubbling the mixed solution, and adding a dehydrating agent and a catalyst; after the addition is completed, heating the reaction system to react; after the reaction is completed, post-treating the product to obtain an acrylic ester pyrrole compound. The stirring method is preferably magnetic stirring; the post-treatment method is preferably: first removing the solvent by reduced pressure distillation, then using petroleum ether and ethyl acetate as eluents, and separating the product by column chromatography.

[0071] The method provided by the present invention uses formaldehyde pyrrole monomer as a starting material, and finally prepares a pyrrole derivative containing an acrylate functional group by designing a reasonable synthesis route; the method is a newly designed reaction path, and provides a new idea for broadening the synthesis methodology of acrylate compounds; and the raw materials used in the method are low in cost, widely available, and highly efficient in reaction, and the product added value is significantly increased, and the method has a wide range of application scenarios.

[0072] For the sake of clarity, the following examples and comparative examples are used to explain in detail. In the following examples of the present invention, the synthetic routes involved are as follows:

[0073]

[0074] In the following embodiments and comparative examples of the present invention, the formaldehyde-based pyrrole monomers used can be purchased from the market or prepared according to the methods disclosed in the prior art; more specifically, 2-pyrrole carboxaldehyde is commercially available, and 3-methylpyrrole-2-carboxaldehyde, 3,5-dimethylpyrrole-2-carboxaldehyde, 3,4-dimethylpyrrole-2-carboxaldehyde, 4,5-dimethylpyrrole-2-carboxaldehyde, and 3,4,5-trimethylpyrrole-2-carboxaldehyde are obtained from references Tetrahedron, 2013, 69, 39, 8375-8385, Organic and Biomolecular Chemistry, 2016, 14, 21, 4829-4841, Tetrahedron, 2013, 69, 39, 8375-8385, Journal of Organic Chemistry, 2011, 76, 20, 8168-8176, Australian Journal of Chemistry, 2011, 76, 20, 8168-8176, Prepared by Journal of Chemistry, 1989, 42, 6, 775-786.

[0075] In the following examples and comparative examples of the present invention, unless otherwise specified, the "parts" mentioned herein refer to molar parts; and the "room temperature" mentioned herein refers to 25°C.

[0076] Example 1

[0077] At room temperature, a three-necked flask equipped with a condenser and a magnetic rotor was dried and subjected to three evacuation-inflating cycles to ensure that the internal atmosphere was a positive pressure nitrogen atmosphere, 1 part of 2-pyrrolecarboxaldehyde and 1.2 parts of sodium hydroxide were added, 62 parts of isopropanol were added, a magnetic stirrer was turned on, 0.02 parts of cobalt tetroxide were added, and the reaction system was heated to 50°C for reaction; after the reaction was completed for 0.5 hours, the reaction degree was monitored by thin layer chromatography to determine the reaction endpoint time, and the total reaction time was about 1 hour; after the reaction was completed and cooled to room temperature, deionized water and ethyl acetate (volume ratio of 1:1) were added to the mixture, and the organic phase was separated after extraction, and the aqueous phase was extracted with a small amount of ethyl acetate. After the organic phases were combined, the solvent was removed by rotary evaporation, and petroleum ether and ethyl acetate (volume ratio of 9:1) were used as eluents, and the products were separated by column chromatography analysis, and finally the solvent was removed by rotary evaporation to obtain 2-ethanolylpyrrole as a colorless liquid; yield: 78.2%, LC-MS (ESI) m / z (M+H) +: 97.09.

[0078] At room temperature, 1 part of the product from the previous step was added to an eggplant-shaped bottle under the protection of a nitrogen atmosphere, 50 parts of anhydrous dimethyl sulfoxide was added, stirring was started, and 4 parts of potassium hydroxide were added. 1.2 parts of 2-bromoethanol were slowly added dropwise to the reaction system through a constant pressure dropping funnel, and the reaction was carried out at room temperature. After the reaction for 12 hours, the reaction process was monitored by thin layer chromatography to determine the reaction endpoint time. The total reaction time was about 13 hours. After the reaction was completed, the solvent was removed by distillation under reduced pressure, and petroleum ether and ethyl acetate (volume ratio of 9:1) were used as eluents. The mixture was quickly separated by a short silica gel pad, and the solvent was removed by rotary evaporation to obtain a colorless oily 2-(2-methanol-1H-pyrrol-1-yl)ethanol; yield: 98.5%, LC-MS (ESI) m / z (M+H)+: 141.12.

[0079] At room temperature, 1 part of the product from the previous step was added to an eggplant-shaped bottle under the protection of a nitrogen atmosphere, 60 parts of anhydrous acetonitrile were added, stirring was started, and nitrogen was bubbled into the solution using a long needle tube. After adding 2.2 parts of acrylic acid, the reaction bottle was moved to an ice water bath and stirred for 0.5 hours; then 2.2 parts of 1,3-dicyclohexylcarbodiimide and 0.2 parts of 4-dimethylaminopyridine were added, and the ice bath was removed after the addition was completed, and the reaction was carried out at room temperature for 5 hours; after the reaction was completed, the solvent was distilled off under reduced pressure, and petroleum ether and ethyl acetate (volume ratio of 4:1) were used as eluents, and the products were separated by column chromatography, and finally the solvent was removed by rotary evaporation to obtain colorless oily 2-(2-methyl acrylate-1H-pyrrol-1-yl) ethyl acrylate; yield: 88.4%, LC-MS (ESI) m / z (M+H) +: 249.18, and the chemical structure is shown in formula (I-1):

[0080]

[0081] Example 2

[0082] At room temperature, a dry three-necked flask equipped with a condenser and a magnetic rotor was subjected to three evacuation-inflation cycles to ensure a positive pressure nitrogen atmosphere inside, 1 part of 3-methylpyrrole-2-carboxaldehyde and 1.2 parts of sodium hydroxide were added, 62 parts of isopropanol were added, a magnetic stirrer was turned on, 0.02 parts of cobalt tetroxide were added, and the reaction system was heated to 50°C for reaction; after reacting for 0.5h, the reaction degree was monitored by thin layer chromatography to determine the reaction endpoint time, and the total reaction time was about 1h; after the reaction was completed and cooled to room temperature, Deionized water and ethyl acetate (volume ratio of 1:1) were added to the mixture. After extraction, the organic phase was separated and the aqueous phase was extracted with a small amount of ethyl acetate. The organic phases were combined and the solvent was removed by rotary evaporation. Petroleum ether and ethyl acetate (volume ratio of 9:1) were used as eluents. The products were separated by column chromatography. Finally, the solvent was removed by rotary evaporation to obtain colorless oily 2-ethanol-3-methylpyrrole; yield: 75.8%, LC-MS (ESI) m / z (M+H) +: 111.08.

[0083] At room temperature, 1 part of the product from the previous step was added to an eggplant-shaped bottle under the protection of a nitrogen atmosphere, 50 parts of anhydrous dimethyl sulfoxide was added, stirring was started, and 4 parts of potassium hydroxide were added. 1.2 parts of 2-bromoethanol were slowly added dropwise to the reaction system through a constant pressure dropping funnel, and the reaction was carried out at room temperature. After the reaction for 12 hours, the reaction process was monitored by thin layer chromatography to determine the reaction endpoint time. The total reaction time was about 13 hours. After the reaction was completed, the solvent was removed by distillation under reduced pressure, and petroleum ether and ethyl acetate (volume ratio of 9:1) were used as eluents. The mixture was quickly separated by a short silica gel pad, and the solvent was removed by rotary evaporation to obtain colorless oily 2-(2-methanol-3-methyl-1H-pyrrol-1-yl)ethanol; yield: 97.1%, LC-MS (ESI) m / z (M+H)+: 155.13.

[0084] At room temperature, 1 part of the product from the previous step was added to an eggplant-shaped bottle under the protection of a nitrogen atmosphere, 60 parts of anhydrous acetonitrile was added, stirring was started, and nitrogen was bubbled into the solution using a long needle tube. After adding 2.2 parts of acrylic acid, the reaction bottle was moved to an ice-water bath and kept stirring for 0.5 hours; then 2.2 parts of 1,3-dicyclohexylcarbodiimide and 0.2 parts of 4-dimethylaminopyridine were added, and the ice bath was removed after the addition was completed, and the reaction was carried out at room temperature for 5 hours; after the reaction was completed, the solvent was distilled off under reduced pressure, and petroleum ether and ethyl acetate (volume ratio of 4:1) were used as eluents, and the products were separated by column chromatography, and finally the solvent was removed by rotary evaporation to obtain colorless oily 2-(2-methyl acrylate-3-methyl-1H-pyrrol-1-yl) ethyl acrylate; yield: 85.4%, LC-MS (ESI) m / z (M+H) +: 263.21, and the chemical structure is shown in formula (I-2):

[0085]

[0086] Example 3

[0087] At room temperature, a dry three-necked flask equipped with a condenser and a magnetic rotor was subjected to three evacuation-inflation cycles to ensure a positive pressure nitrogen atmosphere inside, 1 part of 3,5-dimethylpyrrole-2-carboxaldehyde and 1.2 parts of sodium hydroxide were added, 62 parts of isopropanol were added, a magnetic stirrer was turned on, 0.02 parts of cobalt tetroxide were added, and the reaction system was heated to 50°C for reaction; after reacting for 0.5h, the reaction degree was monitored by thin layer chromatography to determine the reaction endpoint time, and the total reaction time was about 1h; after the reaction was completed and cooled to room temperature, Deionized water and ethyl acetate (volume ratio of 1:1) were added to the mixture. After extraction, the organic phase was separated and the aqueous phase was extracted with a small amount of ethyl acetate. The organic phases were combined and the solvent was removed by rotary evaporation. Petroleum ether and ethyl acetate (volume ratio of 9:1) were used as eluents. The products were separated by column chromatography. Finally, the solvent was removed by rotary evaporation to obtain colorless oily 2-ethanol-3,5-dimethylpyrrole; yield: 71.7%, LC-MS (ESI) m / z (M+H) +: 125.13.

[0088] At room temperature, 1 part of the product from the previous step was added to an eggplant-shaped bottle under the protection of a nitrogen atmosphere, 50 parts of anhydrous dimethyl sulfoxide was added, stirring was started, and 4 parts of potassium hydroxide were added. 1.2 parts of 2-bromoethanol were slowly added dropwise to the reaction system through a constant pressure dropping funnel, and the reaction was carried out at room temperature. After the reaction for 12 hours, the reaction process was monitored by thin layer chromatography to determine the reaction endpoint time. The total reaction time was about 13 hours. After the reaction was completed, the solvent was removed by distillation under reduced pressure, and petroleum ether and ethyl acetate (volume ratio of 9:1) were used as eluents. The mixture was quickly separated by a short silica gel pad, and the solvent was removed by rotary evaporation to obtain a colorless oily 2-(2-methanol-3,5-dimethyl-1H-pyrrol-1-yl)ethanol; yield: 97.6%, LC-MS (ESI) m / z (M+H)+: 169.15.

[0089] At room temperature, 1 part of the product from the previous step was added to an eggplant-shaped bottle under the protection of a nitrogen atmosphere, 60 parts of anhydrous acetonitrile were added, stirring was started, and nitrogen was bubbled into the solution using a long needle tube. After adding 2.2 parts of acrylic acid, the reaction bottle was moved to an ice-water bath and stirred for 0.5 hours; then 2.2 parts of 1,3-dicyclohexylcarbodiimide and 0.2 parts of 4-dimethylaminopyridine were added, and the ice bath was removed after the addition was completed, and the reaction was carried out at room temperature for 5 hours; after the reaction was completed, the solvent was distilled off under reduced pressure, and petroleum ether and ethyl acetate (volume ratio of 4:1) were used as eluents, and the products were separated by column chromatography, and finally the solvent was removed by rotary evaporation to obtain colorless oily 2-(2-methyl acrylate-3,5-dimethyl-1H-pyrrol-1-yl) ethyl acrylate; yield: 88.6%, LC-MS (ESI) m / z (M+H) +: 277.36, and the chemical structure is shown in formula (I-3):

[0090]

[0091] Example 4

[0092] At room temperature, a dry three-necked flask equipped with a condenser and a magnetic rotor was subjected to three evacuation-inflation cycles to ensure a positive pressure nitrogen atmosphere inside, 1 part of 3,4-dimethylpyrrole-2-carboxaldehyde and 1.2 parts of sodium hydroxide were added, 62 parts of isopropanol were added, a magnetic stirrer was turned on, 0.02 parts of cobalt tetroxide were added, and the reaction system was heated to 50°C for reaction; after reacting for 0.5h, the reaction degree was monitored by thin layer chromatography to determine the reaction endpoint time, and the total reaction time was about 1h; after the reaction was completed and cooled to room temperature, Deionized water and ethyl acetate (volume ratio of 1:1) were added to the mixture. After extraction, the organic phase was separated and the aqueous phase was extracted with a small amount of ethyl acetate. The organic phases were combined and the solvent was removed by rotary evaporation. Petroleum ether and ethyl acetate (volume ratio of 9:1) were used as eluents. The products were separated by column chromatography. Finally, the solvent was removed by rotary evaporation to obtain colorless oily 2-ethanol-3,4-dimethylpyrrole; yield: 72.9%, LC-MS (ESI) m / z (M+H) +: 125.11.

[0093] At room temperature, 1 part of the product from the previous step was added to an eggplant-shaped bottle under the protection of a nitrogen atmosphere, 50 parts of anhydrous dimethyl sulfoxide was added, stirring was started, and 4 parts of potassium hydroxide were added. 1.2 parts of 2-bromoethanol were slowly added dropwise to the reaction system through a constant pressure dropping funnel, and the reaction was carried out at room temperature. After the reaction for 12 hours, the reaction process was monitored by thin layer chromatography to determine the reaction endpoint time. The total reaction time was about 13 hours. After the reaction was completed, the solvent was removed by distillation under reduced pressure, and petroleum ether and ethyl acetate (volume ratio of 9:1) were used as eluents. The mixture was quickly separated by a short silica gel pad, and the solvent was removed by rotary evaporation to obtain colorless oily 2-(2-methanol-3,4-dimethyl-1H-pyrrol-1-yl)ethanol; yield: 98.7%, LC-MS (ESI) m / z (M+H)+: 169.13.

[0094] At room temperature, 1 part of the product from the previous step was added to an eggplant-shaped bottle under the protection of a nitrogen atmosphere, 60 parts of anhydrous acetonitrile were added, stirring was started, and nitrogen was bubbled into the solution using a long needle tube. After adding 2.2 parts of acrylic acid, the reaction bottle was moved to an ice-water bath and stirred for 0.5 hours; then 2.2 parts of 1,3-dicyclohexylcarbodiimide and 0.2 parts of 4-dimethylaminopyridine were added, and the ice bath was removed after the addition was completed, and the reaction was carried out at room temperature for 5 hours; after the reaction was completed, the solvent was distilled off under reduced pressure, and petroleum ether and ethyl acetate (volume ratio of 4:1) were used as eluents, and the products were separated by column chromatography, and finally the solvent was removed by rotary evaporation to obtain colorless oily 2-(2-methyl acrylate-3,4-dimethyl-1H-pyrrol-1-yl) ethyl acrylate; yield: 89.4%, LC-MS (ESI) m / z (M+H) +: 277.29, and the chemical structure is shown in formula (I-4):

[0095]

[0096] Example 5

[0097] At room temperature, a dry three-necked flask equipped with a condenser and a magnetic rotor was subjected to three evacuation-inflation cycles to ensure a positive pressure nitrogen atmosphere inside, 1 part of 4,5-dimethylpyrrole-2-carboxaldehyde and 1.2 parts of sodium hydroxide were added, 62 parts of isopropanol were added, a magnetic stirrer was turned on, 0.02 parts of cobalt tetroxide were added, and the reaction system was heated to 50°C for reaction; after reacting for 0.5h, the reaction degree was monitored by thin layer chromatography to determine the reaction endpoint time, and the total reaction time was about 1h; after the reaction was completed and cooled to room temperature, Deionized water and ethyl acetate (volume ratio of 1:1) were added to the mixture. After extraction, the organic phase was separated and the aqueous phase was extracted with a small amount of ethyl acetate. The organic phases were combined and the solvent was removed by rotary evaporation. Petroleum ether and ethyl acetate (volume ratio of 9:1) were used as eluents. The products were separated by column chromatography. Finally, the solvent was removed by rotary evaporation to obtain colorless oily 2-ethanol-4,5-dimethylpyrrole; yield: 73.6%, LC-MS (ESI) m / z (M+H) +: 125.13.

[0098] At room temperature, 1 part of the product from the previous step was added to an eggplant-shaped bottle under the protection of a nitrogen atmosphere, 50 parts of anhydrous dimethyl sulfoxide was added, stirring was started, and 4 parts of potassium hydroxide were added. 1.2 parts of 2-bromoethanol were slowly added dropwise to the reaction system through a constant pressure dropping funnel, and the reaction was carried out at room temperature. After the reaction for 12 hours, the reaction process was monitored by thin layer chromatography to determine the reaction endpoint time. The total reaction time was about 13 hours. After the reaction was completed, the solvent was removed by distillation under reduced pressure, and petroleum ether and ethyl acetate (volume ratio of 9:1) were used as eluents. The mixture was quickly separated by a short silica gel pad, and the solvent was removed by rotary evaporation to obtain colorless oily 2-(2-methanol-4,5-dimethyl-1H-pyrrol-1-yl)ethanol; yield: 96.9%, LC-MS (ESI) m / z (M+H)+: 169.15.

[0099] At room temperature, 1 part of the product from the previous step was added to an eggplant-shaped bottle under the protection of a nitrogen atmosphere, 60 parts of anhydrous acetonitrile were added, stirring was started, and nitrogen was bubbled into the solution using a long syringe. After adding 2.2 parts of acrylic acid, the reaction bottle was moved to an ice-water bath and stirred for 0.5 hours; then 2.2 parts of 1,3-dicyclohexylcarbodiimide and 0.2 parts of 4-dimethylaminopyridine were added, and the ice bath was removed after the addition was completed, and the reaction was carried out at room temperature for 5 hours; after the reaction was completed, the solvent was distilled off under reduced pressure, and petroleum ether and ethyl acetate (volume ratio of 4:1) were used as eluents, and the products were separated by column chromatography, and finally the solvent was removed by rotary evaporation to obtain colorless oily 2-(2-methyl acrylate-4,5-dimethyl-1H-pyrrol-1-yl) ethyl acrylate; yield: 90.1%, LC-MS (ESI) m / z (M+H) +: 277.36, and the chemical structure is shown in formula (I-5):

[0100]

[0101] Comparative Example 1

[0102] At room temperature, 1 part of 2-pyrrolecarboxaldehyde and 1 part of sodium hydroxide were added to the reactor, 62 parts of isopropanol were added, a magnetic stirrer was turned on, 0.01 parts of cobalt tetroxide were added, the reaction system was heated to 50°C, and the reaction was carried out for 0.5h; after the reaction was completed and cooled to room temperature, deionized water and ethyl acetate (volume ratio of 1:1) were added to the mixture, and the organic phase was separated after extraction, and the organic phase was combined and the solvent was removed by rotary evaporation, petroleum ether and ethyl acetate (volume ratio of 9:1) were used as eluents, and the products were separated by column chromatography, and finally the solvent was removed by rotary evaporation to obtain a small amount of colorless liquid 2-ethanol pyrrole; yield: 62.3%, LC-MS (ESI) m / z (M+H) +: 97.07.

[0103] At room temperature, 1 part of the product from the previous step was added to an eggplant-shaped bottle under the protection of a nitrogen atmosphere, 50 parts of dimethyl sulfoxide was added, stirring was started, and 1 part of potassium hydroxide was added. 1 part of 2-bromoethanol was slowly added dropwise to the reaction system through a constant pressure dropping funnel, and the reaction was carried out at room temperature for 12 hours. After the reaction was completed, the solvent was removed by distillation under reduced pressure, and petroleum ether and ethyl acetate (volume ratio of 9:1) were used as eluents. The mixture was quickly separated by passing through a short silica gel pad, and the solvent was removed by rotary evaporation to obtain a small amount of colorless oily 2-(2-methanol-1H-pyrrol-1-yl)ethanol; yield: 47.2%, LC-MS (ESI) m / z (M+H)+: 141.12.

[0104] At room temperature, 1 part of the product from the previous step was added to an eggplant-shaped bottle under nitrogen atmosphere protection, 60 parts of acetonitrile was added, stirring was started, 2.2 parts of acrylic acid was added, and the reaction bottle was moved to an ice-water bath and stirred for 0.5 h; then 2.2 parts of 1,3-dicyclohexylcarbodiimide was added, and the ice bath was removed after the addition was completed, and the reaction was carried out at room temperature for 5 h; after the reaction was completed, the solvent was distilled off under reduced pressure, and petroleum ether and ethyl acetate (volume ratio of 4:1) were used as eluents, and the products were separated by column chromatography, and finally the solvent was removed by rotary evaporation to obtain a small amount of colorless oily 2-(2-methyl acrylate-1H-pyrrol-1-yl) ethyl acrylate; yield: 41.6%, LC-MS (ESI) m / z (M+H) +: 249.15, and the chemical structure is shown in formula (I-1):

[0105]

[0106] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing an acrylic ester pyrrole compound, comprising the following steps: a) reacting a formaldehyde pyrrole monomer of formula (i) with an alkali reagent in the presence of a catalyst and a protective gas to obtain a carbinol pyrrole compound of formula (ii); In step a), the catalyst is cobalt tetroxide, and the alkaline reagent is sodium hydroxide and / or potassium hydroxide; b) reacting the methanol pyrrole compound with a halogenated alcohol in the presence of a catalyst and a protective gas to obtain a hydroxyl-containing pyrrole compound of formula (iii); In step b), the catalyst is one or more of sodium hydroxide, potassium hydroxide, sodium hydride and potassium hydride, and the halogenated alcohol is 2-bromoethanol and / or 2-chloroethanol; c) reacting the hydroxyl-containing pyrrole compound with the acrylic compound of formula (iv) in the presence of a dehydrating agent, a catalyst and a protective gas to obtain an acrylic ester pyrrole compound of formula (I); In step c), the dehydrating agent is 1,3-dicyclohexylcarbodiimide, and the catalyst is 4-dimethylaminopyridine; wherein R1, R2, R3 and R4 are independently selected from -H or -CH3.

2. The preparation method according to claim 1, characterized in that: In step a), the molar ratio of the formaldehyde pyrrole monomer to the alkaline reagent is 1:(1-1.4).

3. The preparation method according to claim 1, characterized in that: In step a), the molar ratio of the formaldehyde pyrrole monomer to the catalyst is 1:(0.01-0.03).

4. The preparation method according to claim 1, characterized in that: In step a), the reaction is carried out in a solvent; the solvent is isopropanol and / or isobutanol.

5. The preparation method according to claim 1, characterized in that: In step a), the reaction temperature is 40-60°C.

6. The preparation method according to claim 1, characterized in that: In step a), the reaction time is 0.5 to 1 h.

7. The preparation method according to claim 1, characterized in that: In step b), the molar ratio of the methanol pyrrole compound to the halogenated alcohol is 1:(1-1.4).

8. The preparation method according to claim 1, characterized in that: In step b), the molar ratio of the methanol pyrrole compound to the catalyst is 1:(4-5).

9. The preparation method according to claim 1, characterized in that: In step b), the reaction is carried out in a solvent; the solvent is one or more of acetonitrile, dimethyl sulfoxide, N,N-dimethylformamide and N,N-dimethylacetamide.

10. The preparation method according to claim 1, characterized in that: In step b), the reaction temperature is 10-40°C.

11. The preparation method according to claim 1, characterized in that: In step b), the reaction time is 10 to 20 hours.

12. The preparation method according to claim 1, characterized in that: In step c), the molar ratio of the hydroxyl pyrrole compound to the acrylic compound is 1:(2-2.4).

13. The preparation method according to claim 1, characterized in that: In step c), the molar ratio of the hydroxyl pyrrole compound to the dehydrating agent is 1:(2-3).

14. The preparation method according to claim 1, characterized in that: In step c), the molar ratio of the hydroxyl pyrrole compound to the catalyst is 1:(0.2-0.3).

15. The preparation method according to claim 1, characterized in that: In step c), the reaction is carried out in a solvent; the solvent is one or more of acetonitrile, dimethyl sulfoxide, N,N-dimethylformamide and N,N-dimethylacetamide.

16. The preparation method according to claim 1, characterized in that: In step c), the reaction temperature is 10-40°C.

17. The preparation method according to claim 1, characterized in that: In step c), the reaction time is 3 to 8 hours.

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