A method for preparing fullerene ester derivatives

Abstract

The invention discloses a method for preparing a fullerene ester derivative, belonging to the field of synthesis of fullerene ester derivatives. The specific method comprises the following steps: using [60]fullerene and iodophenylmalonate as raw materials, and using o-dichlorobenzene as solvent, and subjecting the target product [60]fullerene cyclopropane dicarboxylate compound to a one-step thermal reaction in air. The invention has the advantages of a simple and novel synthesis method, good substrate universality, high yield, etc., and has broad application prospects.

Description

Technical Field

[0001] The present invention belongs to the technical field of synthesis of fullerene derivatives, and in particular relates to a method for preparing a fullerene ester derivative. Background Art

[0002] In 1990, Kräschmer et al. successfully prepared 1% fullerene soot in the laboratory using graphite rod arc evaporation. Since then, more and more methods for synthesizing fullerenes have been discovered. Since it is possible to prepare high-purity fullerenes at low cost, many scientists have been interested in C 60 So far, the application research of fullerene and its derivatives has expanded to many fields, including biology, physics, energy, materials, etc., and has shown great potential and extraordinary application value. 60 Despite its numerous advantages, fullerenes possess a perfect symmetry that renders them completely polar. This, according to the principle of like dissolves like, results in poor solubility in most polar organic solvents, severely limiting the application and development of fullerenes and their derivatives. However, functionalizing the fullerene surface can not only improve its solubility in polar organic solvents but also yield a wider range of structurally diverse fullerene derivatives. Therefore, exploring and developing more chemical reactions for functionalizing fullerenes is crucial. Synthesizing structurally diverse fullerene derivatives has become a current research focus for synthetic scientists. This, in turn, has a positive impact on the potential applications of fullerenes and their derivatives in other fields.

[0003] Fullerene cyclopropane derivatives are an important class of fullerene compounds widely used in the field of organic solar cells. Some fullerene cyclopropane compounds such as PCBM ([6,6]-phenyl-C 61 -butyric acid methylester) has been successfully used as an electron acceptor material for organic solar cells and has been commercialized, attracting widespread attention. It is understood that the following methods are commonly used to prepare fullerene cyclopropane compounds:

[0004] The Bingel reaction is the most effective and classic method for preparing fullerene cyclopropane derivatives (such as Figure 7 However, this method has certain limitations. The reaction not only requires halogen substitution of the substrate, but also requires the use of dangerous metal hydrogen compounds. At the same time, the reaction process releases hydrogen, which adds additional risks.

[0005] In addition, a common method for preparing fullerene cyclopropane compounds is to react with diazo compounds (such as Figure 8For example, the diazo method produces fullerene cyclopropane compounds and 5,6-opened fullerene derivatives (fulleroids). In addition, most diazo compounds must be prepared through complex multi-step reactions, which severely limits the diversity of reaction substrates and makes chemical selectivity difficult to control. The method for synthesizing

[60] fullerene cyclopropane compounds has become mature. However, there are still some prominent problems that have not yet been effectively solved, including the synthesis of water-soluble fullerenes, especially active carbene precursors that can undergo multiple additions to the C=C of fullerenes. Summary of the Invention

[0006] The present invention aims to provide a synthetic route with mild reaction conditions, easy control of chemical selectivity, and a wide variety of reaction substrates to safely prepare fullerene ester derivatives. The present invention decomposes iodine ylides only under heating conditions, which can not only achieve the synthesis of C 60 The molecule can undergo single addition reaction, diaddition, triaddition and tetraaddition reactions. The final product can be further transformed into fullerene ester derivatives or fullerene carboxylic acid derivatives, enhancing the potential application value of fullerene derivatives in various fields.

[0007] The present invention first proposes a method for preparing a fullerene ester derivative, comprising the following steps:

[0008] (1) preparing an iodine ylide compound having the chemical formula shown in formula (I),

[0009]

[0010] Formula (I);

[0011] (2) Fullerene and iodine ylide compound are used as reaction substrates, and a reaction solvent is added to obtain a fullerene ester derivative through an addition reaction under heating conditions; the chemical formula of the fullerene ester derivative is shown in formula (II),

[0012] Formula (I);

[0013] in: represents fullerene, and R1 / R2 are alkyl or alkoxy groups having 1 to 6 carbon atoms.

[0014] Preferably, step (1) comprises Add KOH to acetonitrile and mix evenly, then add iodobenzene acetate, react in an ice-salt bath, stop the reaction and remove acetonitrile to obtain iodine ylide compound.

[0015] The molar ratio of iodobenzene acetate to iodobenzene acetate is 1:1.1.

[0016] Preferably, R1 / R2 is methyl, ethyl or tert-butyl.

[0017] Preferably, R1 / R2 are both methyl, ethyl or tert-butyl.

[0018] Furthermore, the iodine ylide compound in step (1) is dimethyl iodophenylmalonate, diethyl iodophenylmalonate, or di-tert-butyl iodophenylmalonate.

[0019] Preferably, the fullerene is selected from C 60 、C 70 、C 76 、C 78 、C 82 、C 84 At least one of .

[0020] Preferably, in step (2), the molar ratio of fullerene to iodine ylide compound is 1:2-6, the reaction solvent is o-dichlorobenzene, the reaction time is 3-6 min, the reaction temperature is 30-150° C., and the reaction is carried out in air or nitrogen atmosphere.

[0021] Furthermore, in step (2), the molar ratio of fullerene to iodine ylide compound is 1:5, and at 50 o C for 3 minutes. Further, the fullerene ester derivative obtained in step (2) is used to replace the fullerene, and the addition reaction is repeated with the iodine ylide compound according to the reaction conditions of step (2) to obtain a multi-addition product:

[0022] ;

[0023] Where: n is the number of additions, n=2 or 3 or 4.

[0024] Preferably, the structure of the polyaddition product is:

[0025] or or

[0026] .

[0027] Furthermore, the method further comprises hydrolyzing the fullerene ester derivative to obtain fullerene cyclopropanedicarboxylic acid:

[0028] .

[0029] Fullerene cyclopropanedicarboxylic acid has a variety of applications. For example, in CN113372217A, it is hybridized with semiconductor oxide nanoparticles. The hybrid has broad application prospects in the fields of solar photovoltaic conversion and catalysis, especially in novel chemical and photoconversion systems. For example, in CN110960553A, malonic acid-modified fullerene C70 is used to prepare a drug for treating non-alcoholic fatty liver disease. For example, CN104311427A and CN104371114A disclose two derivatives containing a main structure of fullerene cyclopropane dicarboxylic acid as combustion catalysts. Since the existing methods cannot prepare

[60] fullerene cyclopropane dicarboxylic acid with a uniform structure, CN104311427A and CN104371114A first prepare a fullerene monomethyl derivative, and finally react it with fullerene to generate the target product. The uniform structure of

[60] fullerene cyclopropane dicarboxylic acid generated by the present invention can be reacted with oxalyl chloride to generate

[60] fullerene cyclopropane dichloride, which is used as a precursor to react with monomethyl polyglycidyl ether nitrate or monomethyl polyazido glycidyl ether to generate the target products: fullerene polyglycidyl ether nitrate and fullerene polyazido glycidyl ether.

[0030] Furthermore, the method further comprises: hydrolyzing the polyaddition product to obtain a fullerene cyclopropanecarboxylic acid derivative:

[0031] .

[0032] Fullerene cyclopropanecarboxylic acid derivatives have various uses. For example, in CN109053468A, they react with tetramethylammonium hydroxide to produce fullerene triammonium malonate derivatives, which are used to make cathode interface layers and assemble into planar PIN-type perovskite solar cells.

[0033] Preferably, the hydrolysis reaction step is to add hydrated p-toluenesulfonic acid to the fullerene ester derivative or the addition product, dissolve it in a chlorobenzene solution, and heat it at 130°C to carry out the reaction.

[0034] Furthermore, the fullerene is C 60 .

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] 1. The present invention provides a method for preparing fullerene cyclopropane dicarboxylate compounds based on the participation of iodine ylide compounds, which has high yield, good selectivity, and is easy to separate and purify.

[0037] 2. The product has a novel structure and good solubility. The obtained fullerene cyclopropane dicarboxylic acid derivative can be directly dissolved in biocompatible media. The fullerene cyclopropane dicarboxylic acid derivative has a single structural selectivity, a well-defined and uniform structure, and the number of carboxylic acid groups is easily controlled. The derivatized precursor can be separated on a silica gel column, which is low-cost and suitable for large-scale production. This solves the problem of current methods of modifying water solubility, which often result in a mixture of undefined structures. It is also conducive to chemical quantitative analysis and has great potential for future applications in the biological and medical fields.

[0038] 3. The substrate of the present invention has a wide range of applications and good universality, and can be modified with different ester groups as needed.

[0039] 4. Currently, there is no method for preparing

[60] fullerene cyclopropane dicarboxylic acid with uniform structure. In the prior art, bromomalonate and fullerene raw materials are commonly used in the presence of a catalyst to generate fullerene propane dicarboxylate through Binger reaction. The reaction not only requires halogen substitution of the substrate, but also requires the use of dangerous metal hydrogen compounds. At the same time, hydrogen is released during the reaction, which increases additional risks. The generated fullerene propane dicarboxylate is then subjected to alkaline or acid hydrolysis. Since diethyl bromomalonate is difficult to hydrolyze under acidic conditions, alkaline conditions are used for hydrolysis. Under alkaline hydrolysis conditions, the fullerene structure may be destroyed. After verification by CN110028054B, it was found that fullerene C 60 The monoaddition ester is hydrolyzed to the acid and C 60 Fullerenes contain hydroxyl groups, so the hydrolysis products obtained are not uniform. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1

[60] fullerene cyclopropanedicarboxylic acid tert-butyl ester 2a of Example 1 of the present invention 1 H NMR spectrum;

[0041] Figure 2

[60] Fullerene cyclopropane dicarboxylic acid ethyl ester 2b of Example 2 of the present invention 1 H NMR spectrum;

[0042] Figure 3

[60] fullerene cyclopropanedicarboxylic acid methyl ester 2c of Example 3 of the present invention 1 H NMR spectrum;

[0043] Figure 4 This is the reaction process of

[60] fullerene and di-tert-butyl iodophenylmalonate 1a in Example 1 of the present invention;

[0044] Figure 5 This is the preparation process of

[60] fullerene cyclopropanedicarboxylic acid of Example 4 of the present invention;

[0045] Figure 6This is the reaction process of the multi-addition reaction of Examples 5 to 7 of the present invention;

[0046] Figure 7 Preparation of

[60] fullerene cyclopropane derivatives by Bingel reaction in the prior art;

[0047] Figure 8 Preparation of

[60] fullerene cyclopropane derivatives from diazo compounds in the prior art;

[0048] Figure 9

[60] fullerene cyclopropanedicarboxylic acid 3 of Example 4 of the present invention 1 H NMR spectrum;

[0049] Figure 10 This is the reaction process of the iodine ylide compound in the present invention;

[0050] Figure 11 The diaddition

[60] fullerene cyclopropane dicarboxylate 4 of Example 5 of the present invention 1 H NMR spectrum;

[0051] Figure 12 The tri-addition

[60] fullerene cyclopropane dicarboxylate 5 of Example 6 of the present invention 1 H NMR spectrum;

[0052] Figure 13 The tetra-addition

[60] fullerene cyclopropane dicarboxylate 6 of Example 7 of the present invention 1 H NMR spectrum. DETAILED DESCRIPTION

[0053] The above contents of the present invention are further described in detail below through examples, but the contents of the present invention are not limited to these examples.

[0054] Example 1

[0055] In this embodiment, di-tert-butyl iodophenylmalonate 1a and fullerene C are used. 60 Reaction (such as Figure 4 ), generating

[60] fullerene cyclopropane dicarboxylic acid tert-butyl ester as a template reaction, the reaction conditions were optimized in detail, all data are summarized in Table 1. This reaction does not require the addition of additional promoters, the reaction uses o-dichlorobenzene (ODCB) as the reaction solvent, the reaction temperature is 150 o C, the molar ratio of the reaction is C 60:1a is equal to 1:2. After 6 minutes of reaction, a new compound can be obtained with a yield of 15% (column 1, Table 1). The structure was determined to be

[60] fullerene cyclopropanedicarboxylic acid tert-butyl ester 2a by nuclear magnetic resonance hydrogen spectrum analysis. When the equivalent of iodine ylide compound 1a was continuously increased to 6 times (columns 1-4, Table 1), the yield of the product began to decrease, and a higher yield was obtained at 5 times the equivalent (column 3, Table 1). After determining the equivalent of 1a, the reaction temperature was optimized and the reaction temperature was reduced to 30 o C, a 15% yield can be obtained (column 9, Table 1). The reduction of reaction temperature increases the yield (column 5, Table 1), and the reaction temperature is between 40-70 o In the C range, the yield did not change significantly (columns 6-8, Table 1), and it was finally determined that o C, the reaction effect is ideal (column 7 vs columns 5-9, Table 1). In order to eliminate the influence of air on the reaction, we carried out the reaction under nitrogen conditions. The final reaction can maintain a good yield, proving that air has no significant effect on the reaction (column 10 vs column 7, Table 1). Therefore, the optimal reaction conditions are under air conditions, with a molar ratio of: C 60 :1a=1:5, at 50 o C for three minutes (column 7, Table 1).

[0056] According to the reaction in column 7 of Table 1, C 60 (36 mg, 0.05 mmol) and iodine ylide 1a (104.6 mg, 0.25 mmol) were added to a 100 mL round-bottom flask and heated at 50 o C was reacted for 3 min and the unreacted C was separated. 60 (10.2 mg, 28%) and brown amorphous powder target product

[60] fullerene cyclopropane dicarboxylic acid tert-butyl ester 2a (20.7 mg, yield 44%): mp>300 o C; such as Figure 1

[60] Fullerene cyclopropanedicarboxylic acid tert-butyl ester 2a 1 H NMR spectrum 1 H NMR (400 MHz, CS2 / DMSO-d6) δ (ppm): 1.64 (s, 18H).

[0057] Table 1 C 60 Optimization of reaction conditions with di-tert-butyl iodophenylmalonate 1a a

[0058]

[0059] aUnless otherwise stated, all reactions were performed in 6 mL of o-dichlorobenzene (ODCB) under air. b C 60 / 1a / molar ratio. c Isolated yield. The yield in brackets is based on the consumption of C 60 . d The reaction was carried out under nitrogen conditions.

[0060] Among them, the preparation process of iodine ylide compound is as follows Figure 10 The specific steps are as follows:

[0061] Step 1: Weigh KOH solid (2 g, 36 mmol) into a 100 mL reaction flask. Add 20 mL of acetonitrile as the reaction solvent, add the malonate compound (6 mmol), and stir under air for 5 minutes to produce a turbid solution.

[0062] Step 2: Weigh iodobenzene acetate (2.13 g, 6.6 mmol) and add it to the prepared turbid solution. Rapidly apply nitrogen blanket and stir in an ice-salt bath for 2 hours to stop the reaction. Remove the solvent using a rotary evaporator at room temperature and set aside.

[0063] The malonate compound is di-tert-butyl malonate, and the prepared product is di-tert-butyl iodophenylmalonate 1a.

[0064] Under optimal conditions, under heating conditions, according to C 60 :1a=1:5 molar ratio, in o-dichlorobenzene (ODCB), 50 o C was used for the reaction. A simple substrate expansion was conducted, investigating several types of simple and easily synthesized iodine ylides. Different iodine ylides were all able to afford the target compounds in high yields (44-54%), as shown in Examples 2 and 3.

[0065] Example 2

[0066]

[60] Preparation of fullerene cyclopropanedicarboxylic acid ethyl ester 2b:

[0067] Specific preparation steps:

[0068] According to the general steps above, fullerene C 60 (36 mg, 0.05 mmol), diethyl iodophenylmalonate (iodine ylide compound 1b) (83.5 mg, 0.25 mmol) were added to a 100 mL round-bottom flask, and 6 mL of o-dichlorobenzene (ODCB) was added as the reaction solvent. o C was reacted for 7 min and the unreacted C was separated. 60(13.5 mg, 38%) and brown amorphous powder target product 2b (21.0 mg, 48%): mp>300 o C; such as Figure 2

[60] Fullerene cyclopropanedicarboxylic acid ethyl ester 2b 1 H NMR spectrum 1 H NMR (400 MHz, CS2 / DMSO-d6) δ (ppm): 4.46 (q, J = 7.1 Hz, 4H), 1.45 (t, J = 7.1 Hz, 6H).

[0069] Example 3

[0070]

[60] Preparation of fullerene cyclopropanedicarboxylic acid methyl ester 2c:

[0071] The specific preparation steps are:

[0072] According to the general steps above, fullerene C 60 (36 mg, 0.05 mmol), dimethyl iodophenylmalonate (iodo ylide compound 1c) (90.5 mg, 0.25 mmol) were added to a 100 mL round-bottom flask, and 6 mL of o-dichlorobenzene (ODCB) was added as the reaction solvent. o C was reacted for 15 min and the unreacted C was separated. 60 (2.7 mg, 8%) and brown amorphous powder target product 2b (22.9 mg, 54%): mp>300 ℃. Figure 3

[60] Fullerene cyclopropanedicarboxylic acid methyl ester 2c 1 H NMR spectrum 1 H NMR (400 MHz, CS2 / DMSO-d6) δ (ppm): 4.00 (s, 6H).

[0073] In fact, for these complex and diverse compounds, the reported method can also be used to carry out hydrolysis reaction in the presence of hydrated p-toluenesulfonic acid TsOH·H2O to quantitatively obtain fullerene cyclopropanedicarboxylic acid compounds with certain water solubility (such as Figure 5 ). As shown in Example 4.

[0074] Example 4

[0075]

[60] Synthesis of fullerene cyclopropanedicarboxylic acid 3:

[0076]

[60] fullerene cyclopropanedicarboxylic acid butyl ester 2a (18.7 mg, 0.02 mmol) and TsOH·H2O (11.4 mg, 0.06 mmol) were added to a 100 mL round-bottom flask, and the compound was completely dissolved in 6 mL chlorobenzene (CB) by ultrasonic treatment. The resulting reaction solution was placed in a pre-set 130 o The mixture was heated in an oil bath at room temperature and stirred under air. The reaction was monitored by thin layer chromatography (TLC). After the reaction was completed, the mixture was cooled to room temperature and separated and purified by column chromatography. Unreacted

[60] fullerene cyclopropane dicarboxylic acid butyl ester 2a was first obtained using carbon disulfide / dichloromethane as the eluent. Then, the target product 3,

[60] fullerene cyclopropane dicarboxylic acid, was obtained using carbon disulfide / acetic acid as the eluent. The target product 3 was obtained as a brown amorphous powder (yield>95%): mp>300 o C. Such as Figure 9

[60] fullerene cyclopropanedicarboxylic acid 1 H NMR spectrum, and Figure 1 Compared with the lack of characteristic peaks of tert-butyl groups, the ester groups are completely hydrolyzed.

[0077] Similarly, the same method can be used to obtain the corresponding

[60] fullerene carboxylic acid cyclopropanecarboxylic acid for the polyaddition product. This method has certain reference value in the field of synthesizing water-soluble fullerenes and can introduce more structurally rich groups into fullerene molecules.

[0078] Under the optimal conditions, the high reactivity of the substrate di-tert-butyl iodophenylmalonate 1a was utilized, and based on the obtained product

[60] fullerene cyclopropanedicarboxylate butyl ester 2a, as Figure 6 As shown, the reaction was repeated to obtain the diaddition product. Using the same method, after multiple reactions, the triaddition and tetraaddition products were successfully obtained, and the yields were maintained at a good level. For the tetraaddition product, the yield may be reduced due to the influence of steric hindrance. These complex

[60] fullerene cyclopropane compounds have potential application value in various fields. As shown in Examples 5 to 7.

[0079] Example 5

[0080] Synthesis of diaddition

[60] fullerene cyclopropanedicarboxylate 4

[0081] According to the general procedure in Example 1,

[60] fullerene cyclopropanedicarboxylic acid butyl ester 2a (18.7 mg, 0.02 mmol) and di-tert-butyl iodophenylmalonate (iodo ylide compound) 1a (12.5 mg, 0.03 mmol) were added to a 100 mL round-bottom flask, and 6 mL of o-dichlorobenzene (ODCB) was added as the reaction solvent.o C for 8 min, and the unreacted

[60] fullerene cyclopropane dicarboxylate butyl ester 2a (10.5 mg, 56%) and the target product 4, diaddition

[60] fullerene cyclopropane dicarboxylate (8.7 mg, 38%), were separated as a brown amorphous powder: mp>300 o C. Such as Figure 11 is the diaddition of

[60] fullerene cyclopropanedicarboxylate 4 1 H NMR spectrum 1 H NMR (400 MHz, CS2 / DMSO-d6) δ (ppm): 1.73-1.56(m, 36H).

[0082] Example 6

[0083] Synthesis of triaddition

[60] fullerene cyclopropanedicarboxylate 5

[0084] According to the general procedure in Example 5, diaddition

[60] fullerene cyclopropanedicarboxylate 4 (23.0 mg, 0.02 mmol) and di-tert-butyl iodophenylmalonate (iodo ylide compound) 1a (41.8 mg, 0.1 mmol) were added to a 100 mL round-bottom flask, and 6 mL of o-dichlorobenzene (ODCB) was added as the reaction solvent. o C for 8 min, and the unreacted diaddition

[60] fullerene cyclopropane dicarboxylate 4 (3.3 mg, 14%) and the target product 5, triaddition

[60] fullerene cyclopropane dicarboxylate (11.3 mg, 42%), were separated as a brown amorphous powder: mp>300 o C. Such as Figure 12 is a tri-addition

[60] fullerene cyclopropane dicarboxylate 5 1 H NMR spectrum 1 H NMR (400 MHz, CS2 / DMSO-d6) δ (ppm): 1.73-1.45 (m, 54H).

[0085] Example 7

[0086] Synthesis of Tetra-addition

[60] fullerene cyclopropane dicarboxylate 6 According to the general procedure in Example 6, tri-addition

[60] fullerene cyclopropane dicarboxylate 5 (27.3 mg, 0.02 mmol) and di-tert-butyl iodophenylmalonate (iodo ylide compound) 1a (41.8 mg, 0.1 mmol) were added to a 100 mL round-bottom flask, and 6 mL of o-dichlorobenzene (ODCB) was added as the reaction solvent. oC for 15 min, and the unreacted tri-addition

[60] fullerene cyclopropane dicarboxylate 5 (10.1 mg, 37%) and the target product 6, tetra-addition

[60] fullerene cyclopropane dicarboxylate (5.2 mg, 17%), were separated as brown amorphous powder: mp>300 o C. Such as Figure 13 It is a tetraaddition of

[60] fullerene cyclopropanedicarboxylate 6 1 H NMR spectrum 1 H NMR (400 MHz, CS2 / DMSO-d6) δ (ppm): 1.61-1.45 (m, 72H).

Claims

1. A method for preparing a fullerene ester derivative, characterized in that: The following steps are involved: (1) preparing an iodine ylide compound, the chemical formula of which is shown in formula (I), Formula (I); (2) Fullerene and iodine ylide compound are used as reaction substrates, and a reaction solvent is added to obtain a fullerene ester derivative through an addition reaction under heating conditions. The chemical formula of the fullerene ester derivative is shown in formula (II), ; Formula (II) in: represents fullerene, The R1 / R2 is methyl, ethyl or tert-butyl; The iodine ylide compound in step (1) is dimethyl iodophenylmalonate, diethyl iodophenylmalonate, or di-tert-butyl iodophenylmalonate; The fullerene is C 60 ; In step (2), the molar ratio of fullerene to iodine ylide compound is 1:5, the reaction solvent is o-dichlorobenzene, the reaction time is 3 min, and the reaction temperature is 50 o C, the reaction was carried out under air or nitrogen atmosphere.

2. The method for preparing a fullerene ester derivative according to claim 1, characterized in that: The fullerene ester derivative obtained in step (2) is used to replace fullerene, and the addition reaction is repeated with the iodine ylide compound according to the reaction conditions of step (2) to obtain a multi-addition product: Where: n is the number of additions, n=2 or 3 or 4.

3. The method for preparing the fullerene ester derivative according to claim 1, characterized in that: The method further comprises hydrolyzing the fullerene ester derivative to obtain fullerene cyclopropanedicarboxylic acid: .

4. The method for preparing a fullerene ester derivative according to claim 2, characterized in that: The method further comprises hydrolyzing the polyaddition product to obtain a fullerene cyclopropanecarboxylic acid derivative: .

5. The method for preparing a fullerene ester derivative according to claim 3 or 4, characterized in that: The hydrolysis reaction step is to add hydrated p-toluenesulfonic acid to the fullerene ester derivative or the polyaddition product, dissolve it in a chlorobenzene solution, and heat it at 130° C. to react.

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