CN111285827A - Preparation method of novel difurane compound - Google Patents

Abstract

The invention belongs to the field of organic synthesis, and particularly relates to a preparation method of a novel difuran compound, wherein a furan ring compound shown in a formula 1 and a carbonyl-containing compound shown in a formula 2 are adopted to generate the difuran compound shown in a formula 4 under the catalysis of o-diphenyldisulfonimide shown in a formula 3.

Description

A kind of preparation method of novel bisfuran compounds

technical field

The invention belongs to the field of organic synthesis, and particularly relates to a preparation method of a novel bisfuran compound.

Background technique

Over the past century, the widespread use of fossil resources has led to their dwindling supply and soaring oil prices. And carbon dioxide from the burning of fossil fuels may also contribute to global climate change. Due to these issues, there is currently a great deal of attention to renewable and sustainable resources. In particular, furan compounds, which can be derived from atmospheric carbon dioxide photosynthetic carbohydrate biomass, have attracted interest as promising alternatives to aromatic compounds that have so far relied entirely on petroleum reforming processes. For example, 2,5-furandicarboxylic acid (FDCA) is believed to be a substitute for terephthalic acid, a diacid monomer used to make polyethylene terephthalate. Globally, there are abundant polymeric carbohydrates, such as cellulose and hemicellulose, which can be depolymerized into monosaccharides, hexoses (glucose from cellulose) and pentoses (xylose from hemicellulose). Following catalytic dehydration reactions, monosaccharides can be converted into furfural intermediates [5-hydroxymethyl-2-furfural (HMF) from hexose, and 2-furfural from pentoses]. Subsequent oxidation or reduction reactions can generate various furan compounds.

Bisphenol A (BPA) and bisphenol A monomers are often used in industry to synthesize polycarbonate (PC) and epoxy resins and other materials. It has been used since the 1960s to make plastic bottles, sippy cups for toddlers, and the inner coating of food and beverage cans. However, the materials prepared from bisphenol A will degrade during application to produce some toxic substances, which have extensive adverse effects on organisms. With the development of industrialization and the wide application of plastic products and epoxy resins, the demand for BPA has increased, resulting in an increase in the emission of BPA pollutants in the environment, causing serious environmental pollution. Bifuran compounds (polymerizable monomers) having a structure in which two furan rings are bonded together by a hydrocarbon group or the like have attracted attention as biobased raw materials having structures similar to bisphenol-type compounds. Since the furan ring has similar rigidity and properties to the benzene ring, the polymers such as polyesters prepared by replacing bisphenol A-type furan monomers with bisphenol-A compounds can have a certain rigidity and a higher glass transition temperature. It has a wider range of applications and has great market prospects.

Regarding the synthesis of bisfurandioic acid, known methods include Gandini et al. Most of them start with furfural, through catalytic alkylation, then deprotection, and reduction to obtain bisphenol A-type furan monomer. The route is relatively complicated at first. Most of the reaction catalysts are strong acids with great harm, such as concentrated sulfuric acid, and the yield is low and the post-treatment is cumbersome.

SUMMARY OF THE INVENTION

In order to solve the above problems, the present invention aims to construct a new method for synthesizing bisfuran compounds, which is a synthetic process that uses safer catalysts, makes the reaction conditions milder or the post-treatment of the reaction more convenient.

The specific plans are as follows:

A preparation method of a novel bisfuran compound, the furan ring compound shown in formula 1 and the carbonyl-containing compound shown in formula 2 are generated as shown in formula 4 under the catalysis of phthalimide shown in formula 3 The bisfurans:

in:

R ₁ and R ₂ are selected from the same or different substituents in hydrogen, alkyl of 1 to 3 carbon atoms, substituted or unsubstituted phenyl, and the alkyl described here includes saturated or unsaturated alkyl ;

R ₃ is selected from an alkyl group of 1-3 carbon atoms, an ester group, an aldehyde group or an amino-substituted alkyl group of 1-3 carbon atoms. The alkyl group mentioned here includes saturated or unsaturated alkyl groups, and the ester group refers to -COOR, wherein R is generally a non-hydrogen group such as an alkyl group.

Preferably, R ₁ and R ₂ are selected from the same or different substituents in hydrogen, methyl, ethyl, or phenyl; R ₃ is selected from methyl, methyl formate, ie -COOCH ₃ , ethyl formate , ie -COOCH ₂ or aminomethyl ₂ HN-CH ₂ -.

Preferably, the furan ring compound shown in the following table and the carbonyl-containing compound shown in the formula 2 are respectively used to generate the following formula 4 under the catalysis of the phthalimide shown in the formula 3. The bisfurans shown:

Preferably, the reaction temperature of the preparation method is 80-110°C.

Preferably, the reaction of the preparation method is carried out in a polar aprotic solvent.

Preferably, the apolar protic solvent should preferably be an aprotic solvent resistant to a high temperature of 80°C.

Preferably, the solvent of the preparation method is one or more of toluene, DMSO, DMF or xylene.

Preferably, in the specific reaction process, the carbonyl-containing compound shown in formula 2 is slowly added to the furan ring compound shown in formula 1 to carry out the reaction. "Slow" here depends on the size of the reaction. In small-scale laboratory applications, the addition may be at a rate of about one drop per second, but in scale-up applications, it depends on the scale, as is well known to those skilled in the art.

Beneficial effects:

Compared with the prior art, the present invention has at least one of the following advantages:

1. The reaction route is shorter and the synthesis method is simpler;

2. The reaction conditions are milder and the operation is safer;

3. The reaction is greener and less harmful;

4. The post-reaction treatment is simpler;

5. The substrate adaptability is wider;

6. The furan ring is aromatic and can be derived from a wide range of carbohydrates. Its properties are similar to the benzene ring. It can be used to partially replace monomers such as petroleum-based terephthalic acid and bisphenol A.

Description of drawings

Fig. 1 is the characterization diagram of the hydrogen NMR spectrum of the M1 structure of the product obtained in Example 1

Fig. 2 is the carbon nuclear magnetic spectrum characterization diagram of the M1 structure of the product obtained in Example 1

Fig. 3 is the hydrogen NMR characterization diagram of the structure of the product M7 obtained in Example 9

specific embodiment

In order to facilitate the understanding of those skilled in the art, the concept of the present invention will be further described below with reference to the embodiments. The specific descriptions of the following embodiments are not intended to limit the present invention, but are only for the convenience of those skilled in the art to understand the technical solutions. The following Tables 1 and 2 are the relevant purchase information of the raw materials and instruments used in the following examples, and all products are purchased from the market.

Table 1 Source and purity of reagents

Table 2 Instruments and Equipment

In formula 1, when R ₃ is an alkyl group, 1 can be 1a methylfuran; when R ₃ is an ester group, 1 can be 1b methyl furoate, 1c ethyl furoate; wherein R ₃ is aminoalkyl , 1 can be 1d furfurylamine.

In formula 2, when R ₁ =R ₂ =H, the structure is 2a, which is formaldehyde; when R ₁ =H, R ₂ =CH ₃ , the structure is 2b, which is acetaldehyde; wherein R ₁ =H, R ₂ When =CH ₂ -CH ₃ , the structure is 2c, which is propionaldehyde; when R ₁ =H, R ₂ =Ph, the structure is 2d, which is benzaldehyde; when R1 =CH ₃ , R ₂ =CH ₃ , the structure is is 2e, which is acetone.

Example 1

Take 5.00 g (0.04 mol) of methyl 2-furoate (1b) and fully dissolve it in 20 ml of toluene solution, and then take 0.88 g (0.004 mol) of phthalimide (c) and add it to the above toluene solution. Stir at room temperature to fully dissolve. 1.5 equivalents (0.06 mol) of acetaldehyde (2b) was weighed into a constant pressure dropping funnel, and dropped into the toluene solution at a rate of one drop per second. After the dropwise addition, the temperature was raised to 90°C, and the reaction was stirred for 5h. The progress of the reaction was monitored by TLC (PE:EA=5:1) during this period. When the starting point disappeared, the solution was spun dry. The product was subjected to column chromatography on a silica gel column. The obtained pure M1 (white solid) was dried in a vacuum drying oven, and the yield was ≈85% by weighing. (The characterization of the nuclear magnetic structure is shown in Figures 1 and 2).

Example 2

Take 5.00 g (0.04 mol) of methyl 2-furoate (1b) and fully dissolve it in 20 ml of toluene solution, and then take 0.88 g (0.004 mol) of phthalimide (c) and add it to the above toluene solution. Stir at room temperature to fully dissolve. 1.5 equivalents (0.06 mol) of acetaldehyde (2b) was weighed into a constant pressure dropping funnel, and dropped into the toluene solution at a rate of one drop per second. After the dropwise addition, the temperature was raised to 80°C, and the reaction was stirred for 5h. The progress of the reaction was monitored by TLC (PE:EA=5:1) during this period. When the starting point disappeared, the solution was spun dry. The product was subjected to column chromatography on a silica gel column. The obtained pure M1 (white solid) was dried in a vacuum drying oven, and the yield was ≈72% by weighing.

Example 3

Take 5.00 g (0.04 mol) of methyl 2-furoate (1b) and fully dissolve it in 20 ml of toluene solution, and then take 0.88 g (0.004 mol) of phthalimide (c) and add it to the above toluene solution. Stir at room temperature to fully dissolve. 1.5 equivalents (0.06 mol) of acetaldehyde (2b) was weighed into a constant pressure dropping funnel, and dropped into the toluene solution at a rate of one drop per second. After the dropwise addition, the temperature was raised to 100 °C, and the reaction was stirred for 5 h. The progress of the reaction was monitored by TLC (PE:EA=5:1) during this period. When the starting point disappeared, the solution was spun dry. The product was subjected to column chromatography on a silica gel column. The obtained pure M1 (white solid) was dried in a vacuum drying oven, and the yield was ≈86% by weighing.

Example 4

Take 5.00 g (0.04 mol) of methyl 2-furoate (1b) and fully dissolve it in 20 ml of toluene solution, and then take 0.88 g (0.004 mol) of phthalimide (c) and add it to the above toluene solution. Stir at room temperature to fully dissolve. 1.5 equivalents (0.06 mol) of acetaldehyde (2b) was weighed into a constant pressure dropping funnel, and dropped into the toluene solution at a rate of one drop per second. After the dropwise addition, the temperature was raised to 110 °C, and the reaction was stirred for 5 h. The progress of the reaction was monitored by TLC (PE:EA=5:1) during this period. When the starting point disappeared, the solution was spun dry. The product was subjected to column chromatography on a silica gel column. The obtained pure M1 (white solid) was dried in a vacuum drying oven, and the yield was ≈84% by weighing.

Example 5

Take 5.61 g (0.04 mol) of ethyl 2-furoate (1c) and fully dissolve it in 20 ml of toluene solution, and then take 0.88 g (0.004 mol) of phthalimide (c) and add it to the above toluene solution. Stir at room temperature to fully dissolve. 1.5 equivalents (0.06 mol) of acetone (2e) were weighed into a constant pressure dropping funnel, and dropped into the toluene solution at a rate of one drop per second. After the dropwise addition, the temperature was raised to 90°C, and the reaction was stirred for 5h. The progress of the reaction was monitored by TLC (PE:EA=5:1) during this period. When the starting point disappeared, the solution was spun dry. The product was subjected to column chromatography on a silica gel column. The obtained pure M9 (white solid) was dried in a vacuum drying oven, and the yield was ≈68% by weighing.

Example 6

Take 5.00 g (0.04 mol) of methyl 2-furoate (1b) and fully dissolve it in 20 ml of toluene solution, and then take 0.88 g (0.004 mol) of phthalimide (c) and add it to the above toluene solution. Stir at room temperature to fully dissolve. 1.5 equivalents (0.06 mol) of propionaldehyde (2c) were weighed into a constant pressure dropping funnel, and dropped into the toluene solution at a rate of one drop per second. After the dropwise addition, the temperature was raised to 90°C, and the reaction was stirred for 5h. The progress of the reaction was monitored by TLC (PE:EA=5:1) during this period. When the starting point disappeared, the solution was spun dry. The product was subjected to column chromatography on a silica gel column. The obtained pure M3 (yellow solid) was dried in a vacuum drying oven, and the yield was ≈70% by weighing.

Example 7

Take 5.00 g (0.04 mol) of methyl 2-furoate (1b) and fully dissolve it in 20 ml of toluene solution, and then take 0.88 g (0.004 mol) of phthalimide (c) and add it to the above toluene solution. Stir at room temperature to fully dissolve. Weigh 1.5 equivalents (0.06 mol) of benzaldehyde (2d) into a constant pressure dropping funnel, and drop into the above toluene solution at a rate of one drop per second. After the dropwise addition, the temperature was raised to 90°C, and the reaction was stirred for 5h. The progress of the reaction was monitored by TLC (PE:EA=5:1) during this period. When the starting point disappeared, the solution was spun dry. The product was subjected to column chromatography on a silica gel column. The obtained pure M4 (yellow solid) was dried in a vacuum drying oven, and the yield was ≈50% by weighing.

Example 8

3.28g (0.04mol) of 2-methylfuran (1a) was fully dissolved in 20ml of toluene solution, and 0.88g (0.004mol) of phthalimide (c) was added to the above toluene solution. Stir at room temperature to fully dissolve. 1.5 equivalents (0.06 mol) of acetaldehyde (2b) was weighed into a constant pressure dropping funnel, and dropped into the toluene solution at a rate of one drop per second. After the dropwise addition, the temperature was raised to 90°C, and the reaction was stirred for 5h. The progress of the reaction was monitored by TLC (PE:EA=5:1) during this period. When the starting point disappeared, the solution was spun dry. The product was subjected to column chromatography on a silica gel column. The obtained pure M5 (yellow liquid) was dried in a vacuum drying oven, and the yield was ≈80% by weighing.

Example 9

Take 3.88g (0.04mol) of 2-furfurylamine (1d) and fully dissolve it in 20ml of toluene solution, and then take 0.88g (0.004mol) of phthalimide (c) and add it to the above toluene solution. Stir at room temperature to fully dissolve. 1.5 equivalents (0.06 mol) of acetone (2e) were weighed into a constant pressure dropping funnel, and dropped into the toluene solution at a rate of one drop per second. After the dropwise addition, the temperature was raised to 90°C, and the reaction was stirred for 5h. The progress of the reaction was monitored by TLC (PE:EA=5:1) during this period. When the starting point disappeared, the solution was spun dry. The crude product was dissolved in ethyl acetate and neutralized with 10% sodium hydroxide solution to adjust pH=7-8. It was extracted three times with ethyl acetate, dried with anhydrous magnesium sulfate, filtered, and distilled under reduced pressure to obtain pure M7 (brown liquid), which was weighed to obtain a yield of ≈ 50%. (The NMR structure characterization is shown in Figure 3).

Example 10

3.28g (0.04mol) of 2-methylfuran (1a) was fully dissolved in 20ml of toluene solution, and 0.88g (0.004mol) of phthalimide (c) was added to the above toluene solution. Stir at room temperature to fully dissolve. 1.5 equivalents (0.06 mol) of acetone (2e) were weighed into a constant pressure dropping funnel, and dropped into the toluene solution at a rate of one drop per second. After the dropwise addition, the temperature was raised to 90°C, and the reaction was stirred for 5h. The progress of the reaction was monitored by TLC (PE:EA=5:1) during this period. When the starting point disappeared, the solution was spun dry. The product was subjected to column chromatography on a silica gel column. The obtained pure M6 (orange liquid) was dried in a vacuum drying oven, and the yield was ≈80% by weighing.

Example 11

3.28g (0.04mol) of 2-methylfuran (1a) was fully dissolved in 20ml of toluene solution, and 0.88g (0.004mol) of phthalimide (c) was added to the above toluene solution. Stir at room temperature to fully dissolve. 1.5 equivalents (0.06 mol) of formaldehyde (2a) was weighed into a constant pressure dropping funnel, and dropped into the toluene solution at a rate of one drop per second. After the dropwise addition, the temperature was raised to 90°C, and the reaction was stirred for 5h. The progress of the reaction was monitored by TLC (PE:EA=5:1) during this period. When the starting point disappeared, the solution was spun dry. The product was subjected to column chromatography on a silica gel column. The obtained pure M11 (light yellow liquid) was dried in a vacuum drying oven, and the yield was ≈72% by weighing.

Example 12

Take 5.00 g (0.04 mol) of methyl 2-furoate (1b) and fully dissolve it in 20 ml of toluene solution, and then take 0.88 g (0.004 mol) of phthalimide (c) and add it to the above toluene solution. Stir at room temperature to fully dissolve. 1.5 equivalents (0.06 mol) of acetaldehyde (2b) was weighed into a constant pressure dropping funnel, and dropped into the toluene solution at a rate of one drop per second. After the dropwise addition, the temperature was raised to 90°C, and the reaction was stirred for 5h. The progress of the reaction was monitored by TLC (PE:EA=5:1) during this period. When the starting point disappeared, the solution was spun dry. The product was subjected to column chromatography on a silica gel column. The resulting pure M1 (white solid) was dried in a vacuum oven.

M1 was dissolved in ethyl acetate solution and hydrolyzed with sodium hydroxide catalyzed at 60°C, and the reaction progress was monitored by spot plate. After the reaction, the pH was adjusted to be acidic. Extracted three times with ethyl acetate, dried with anhydrous magnesium sulfate, filtered, and dried in a vacuum drying oven to obtain pure M8 (off-white solid), and the yield was ≈ 60% by weighing.

The structure of M8 is:

Example 13

Take 5.00 g (0.04 mol) of methyl 2-furoate (1b) and fully dissolve it in 20 ml of toluene solution, and then take 0.88 g (0.004 mol) of phthalimide (c) and add it to the above toluene solution. Stir at room temperature to fully dissolve. 1.5 equivalents (0.06 mol) of acetaldehyde (2b) was weighed into a constant pressure dropping funnel, and dropped into the toluene solution at a rate of one drop per second. After the dropwise addition, the temperature was raised to 90°C, and the reaction was stirred for 5h. The progress of the reaction was monitored by TLC (PE:EA=5:1) during this period. When the starting point disappeared, the solution was spun dry. The product was subjected to column chromatography on a silica gel column. The obtained pure M1 was dried in a vacuum drying oven.

M1 was dissolved in ethyl acetate solution and hydrolyzed with sodium hydroxide catalyzed at 60°C, and the reaction progress was monitored by spot plate. After the reaction, the pH was adjusted to be acidic. It was extracted three times with ethyl acetate, and dried with anhydrous magnesium sulfate. After filtration, the obtained pure M8 was dried in a vacuum drying oven.

The bisfurandioic acid M8 is reduced by LiAlH4 catalytic hydrogenation to obtain the product M10 (pale yellow liquid).

M10 structure is:

Claims (7)

1. a preparation method of a novel difuran compound is characterized in that a furan ring compound shown as a formula 1 and a carbonyl-containing compound shown as a formula 2 generate the difuran compound shown as a formula 4 under the catalysis of o-diphenyldisulfonimide shown as a formula 3:

wherein:

R₁and R₂The same or different substituents are selected from hydrogen, alkyl with 1-3 carbon atoms and substituted or unsubstituted phenyl;

R₃selected from alkyl with 1 to 3 carbon atoms, ester group, aldehyde group or alkyl with 1 to 3 carbon atoms substituted by amino.

2. The production method according to claim 1,

R₁and R₂Identical or different substituents from the group consisting of hydrogen, methyl, ethyl or phenyl;

R₃selected from methyl, carbomethoxy or aminomethyl.

3. The preparation method according to claim 1, wherein the furan ring compound represented by formula 1 and the carbonyl group-containing compound represented by formula 2 are catalyzed by orthophthalimide represented by formula 3 to form a bis-furan compound represented by the following formula 4:

4. the preparation method according to claim 1, wherein the reaction temperature of the preparation method is 80-110 ℃.

5. The process according to claim 1, wherein the reaction is carried out in a polar aprotic solvent.

6. The method of claim 1, wherein the reaction is carried out in one or more solvents selected from toluene, DMSO, DMF, and xylene.

7. The method according to claim 1, wherein the carbonyl group-containing compound represented by formula 2 is slowly added to the furan ring-type compound represented by formula 1 during the reaction.

Images