Diethyl-2-(hydroxymethyl)-2, 3-dioxythieno [3, 4-b] [1, 4] dioxin-5, 7-dicarboxylate and preparation method thereof

Abstract

The invention discloses a preparation method of diethyl-2-(hydroxymethyl)-2, 3-dioxythieno [3, 4-b] [1, 4] dioxin-5, 7-dicarboxylate, which is characterized by comprising the following steps: (1) mixing 2, 5-dicarboxylic acid diethyl ester-3, 4-dihydroxythiophene and 2, 3-dibromo-1-propanol in a solvent, and reacting under the action of a catalyst; (2) after the reaction is finished, carrying out suction filtration, washing and drying to obtain a crude product; (3) recrystallizing the crude product to obtain a high-purity product; and (4) recovering and recycling the solvent and the catalyst. By recycling the solvent and the catalyst, the utilization efficiency of resources is improved, and the environmental pollution is reduced; reaction conditions are optimized, and the yield and purity of DE-THDD are improved; the purification process is simplified, the production cost is reduced, and the economic benefit is improved.

Description

Technical Field

[0001] The present invention relates to the field of organic synthesis, and in particular to a method for preparing diethyl-2-(hydroxymethyl)-2,3-dioxythieno[3,4-b][1,4]dioxin-5,7-dicarboxylate. The method utilizes the reaction of 2,5-diethyl dicarboxylate-3,4-dihydroxythiophene and 2,3-dibromo-1-propanol, and realizes industrial large-scale production by exploring reaction conditions such as solvents. Background Art

[0002] Diethyl-2-(hydroxymethyl)-2,3-dioxothieno[3,4-b][1,4]dioxin-5,7-dicarboxylate (DE-THDD), as a key thiophene organic compound, plays a pivotal role in many industries. As an important organic synthesis intermediate, it is widely used in the fields of pharmaceutical chemistry and materials science. In drug synthesis, it can be used to construct molecular structures with biological activity; in materials science, it can be used to synthesize polymer materials and optoelectronic materials with special properties. However, the traditional method for preparing DE-THDD has a low yield and high cost. This method achieves a low preparation cost. The pollution to the environment is reduced by recycling the solvent and catalyst.

[0003] Through this method, we not only reduced the production cost of DE-THDD and reduced the impact on the environment, but also improved production efficiency. This innovative preparation process provides a new idea for the sustainable production of thiophene organic compounds, and is expected to have a far-reaching impact in many fields such as chemical industry, medicine and agriculture. With the increasing awareness of environmental protection and resource recycling, the promotion and application of this technology will have important social and economic value. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a method for preparing diethyl-2-(hydroxymethyl)-2,3-dioxythieno[3,4-b][1,4]dioxin-5,7-dicarboxylate. The method uses 2,5-diethyl dicarboxylate-3,4-dihydroxythiophene and 2,3-dibromo-1-propanol as key reactants, and recycles solvents and catalysts to significantly improve the reaction conversion rate and product purity, while reducing production costs and environmental pollution.

[0005] The technical scheme of the present invention is: a method for preparing diethyl-2-(hydroxymethyl)-2,3-dioxythieno[3,4-b][1,4]dioxin-5,7-dicarboxylate, comprising: (1) mixing 2,5-diethyl dicarboxylate-3,4-dihydroxythiophene and 2,3-dibromo-1-propanol in a solvent and reacting them under the action of a catalyst; (2) after the reaction, obtaining a crude product by suction filtration, washing and drying; (3) recrystallizing the crude product to obtain a high-purity product; and (4) recovering and recycling the solvent and the catalyst.

[0006] A product with a purity of 95% was obtained, and the raw material ratio was hydroxy 2,5-dicarboxylic acid diethyl ester-3,4-dihydroxythiophene: 2,3-dibromo-1-propanol = 1:1.5.

[0007] The solvent is dimethylformamide, which is recovered and recycled through high-temperature distillation.

[0008] The catalyst is potassium carbonate, which is recovered by suction filtration.

[0009] The reaction was carried out at 100 degrees Celsius for 8 hours.

[0010] The product was recrystallized from anhydrous ethanol.

[0011] The purity of the product is not less than 95%, and the yield is not less than 90%.

[0012] Beneficial effects of the present invention: Compared with the prior art, the present invention has the following advantages:

[0013] By recycling solvents and catalysts, the utilization efficiency of resources is improved and environmental pollution is reduced;

[0014] The reaction conditions were optimized to improve the yield and purity of DE-THDD; currently, the yield and purity that other processes can achieve are 80% and 85% respectively.

[0015] The current purification method is to separate the product by column chromatography, which requires a large amount of solvent. The present invention adds a flocculant and lowers the temperature to allow the product to recrystallize, thereby simplifying the purification process, reducing production costs and improving economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is the nuclear magnetic hydrogen spectrum of the product of Example 1 of the present application, and various characteristic hydrogens correspond one to one;

[0017] Figure 2 This is the nuclear magnetic hydrogen spectrum of the product of Example 2 of the present application, and various characteristic hydrogens correspond one to one;

[0018] Figure 3This is the H NMR spectrum of the product of Example 3 of the present application, in which various characteristic hydrogens correspond one to one. DETAILED DESCRIPTION

[0019] Example 1: Add 2.6g of 2,5-diethyl dicarboxylate-3,4-dihydroxythiophene (10mmol), 20ml DMF and 2.76g (20mmol) potassium carbonate into a three-necked flask, add 4.36g of 2,3-dibromo-1-propanol (20mmol) dropwise, and react at 100 degrees Celsius for 8 hours. After the reaction is completed, a crude product and potassium carbonate are obtained by suction filtration, washing and drying. The product is purified by ethanol recrystallization to obtain high-purity DE-THDD with a purity of 93% and a yield of 89%. The evaporated solvent and the recovered potassium carbonate are put into the next cycle reaction, and 100% recycling can be achieved.

[0020] Example 2: Add 5.2g of 2,5-diethyl dicarboxylate-3,4-dihydroxythiophene (20mmol) and 40ml DMF, and 5.52g (40mmol) potassium carbonate into a three-necked flask, add 4.36g of 2,3-dibromo-1-propanol (40mmol) dropwise, and react at 100 degrees Celsius for 8 hours. After the reaction is completed, the crude product and potassium carbonate are obtained by suction filtration, washing and drying. The product is purified by ethanol recrystallization to obtain high-purity DE-THDD with a purity of 94% and a yield of 90%. The evaporated solvent and the recovered potassium carbonate are put into the next cycle reaction, and 100% recycling can be achieved.

[0021] Example 3: Add 20g of 2,5-diethyl dicarboxylate-3,4-dihydroxythiophene (77mmol) and 100ml DMF, and 21.28g (154mmol) potassium carbonate into a three-necked flask, add 33.56g of 2,3-dibromo-1-propanol (154mmol) dropwise, and react at 100 degrees Celsius for 8 hours. After the reaction is completed, the crude product and potassium carbonate are obtained by suction filtration, washing and drying. The product is purified by ethanol recrystallization to obtain high-purity DE-THDD with a purity of 95% and a yield of 90%. The evaporated solvent and the recovered potassium carbonate are put into the next cycle reaction, and 100% recycling can be achieved.

[0022] The above embodiments are only preferred embodiments of the present invention, and their purpose is to illustrate the technical solution of the present invention, and not to limit the protection scope of the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing diethyl-2-(hydroxymethyl)-2,3-dioxythieno[3,4-b][1,4]dioxin-5,7-dicarboxylate, characterized in that: (1) Mixing 2,5-diethyl dicarboxylate-3,4-dihydroxythiophene and 2,3-dibromo-1-propanol in a solvent and reacting them in the presence of a catalyst; (2) After the reaction, obtaining a crude product by suction filtration, washing and drying; (3) Recrystallizing the crude product to obtain a high-purity product; and (4) Recovering and recycling the solvent and catalyst.

2. The method for preparing diethyl-2-(hydroxymethyl)-2,3-dioxythieno[3,4-b][1,4]dioxin-5,7-dicarboxylate according to claim 1, characterized in that: A product with a purity of 95% was obtained, and the raw material ratio was hydroxy 2,5-dicarboxylic acid diethyl ester-3,4-dihydroxythiophene: 2,3-dibromo-1-propanol = 1:1.

5.

3. The method for preparing diethyl-2-(hydroxymethyl)-2,3-dioxythieno[3,4-b][1,4]dioxin-5,7-dicarboxylate according to claim 1, characterized in that: The solvent is dimethylformamide, which is recovered and recycled through high-temperature distillation.

4. The method for preparing diethyl-2-(hydroxymethyl)-2,3-dioxythieno[3,4-b][1,4]dioxin-5,7-dicarboxylate according to claim 1, characterized in that: The catalyst is potassium carbonate, which is recovered by suction filtration.

5. The method for preparing diethyl-2-(hydroxymethyl)-2,3-dioxythieno[3,4-b][1,4]dioxin-5,7-dicarboxylate according to claim 1, characterized in that: The reaction was carried out at 100 degrees Celsius for 8 hours.

6. The method for preparing diethyl-2-(hydroxymethyl)-2,3-dioxythieno[3,4-b][1,4]dioxin-5,7-dicarboxylate according to claim 1, characterized in that: The product was recrystallized from anhydrous ethanol.

7. The method for preparing diethyl-2-(hydroxymethyl)-2,3-dioxythieno[3,4-b][1,4]dioxin-5,7-dicarboxylate according to claim 1, characterized in that: The purity of the product is not less than 95%, and the yield is not less than 90%.

Images