JP5861884B2 - Method for producing exo-type norbornene compound - Google Patents

Description

  The present invention relates to a method for producing an exo-type norbornene compound.

  2-Acyl-5-norbornenes are useful as raw material precursors for monomers for electronic materials and optical materials, for example, and are reduced to methylol groups or oxidized to carboxylic acids, esters, acid halides, etc. It is used. In particular, exo isomers are known to be superior in polymerization characteristics and optical properties compared to end isomers (see Patent Documents 1 to 4).

2-Substituted-5-norbornenes are produced by Diels-Alder reaction, and it is well known that endo adducts are obtained preferentially in this reaction (see Non-Patent Document 1). Attempts have been made to exo-enrich this endrich adduct by epimerization reaction in an alkali hydroxide solution or a metal alcoholate solution (see Patent Document 5 and Non-Patent Documents 2 to 4). However, when these solid bases are used, in addition to the industrial disadvantage of making the reaction system diluted and dissolved with a solvent to facilitate the reaction, in the case of an aldehyde group (R = H), a base is used. There is also a drawback that the exo (enriched) product cannot be obtained in a high yield due to side effects such as acetalization reaction, aldol condensation reaction, polymerization reaction, resinification, etc. due to its too strong properties.

Special table 2011-503004 gazette Special table 2010-522254 gazette JP 2007-261980 A JP 2006-160712 A Japanese translation of PCT publication No. 03-505542

J. et al. Furukawa et al., J. MoI. Am. Chem. Soc. , 92, 6548 (1970) R. S. Bly et al. Org. Chem. , 34, 2346 (1969) F. Kasper, J .; prakt. Chem. , 311, 201 (1969) J. et al. G. Dinwiddie et al. Org. Chem. , 30, 766 (1965)

  The object of the present invention is to provide a process for producing norbornene compounds, particularly 2-acyl-5-norbornenes, containing many exo-forms useful as raw material precursors for monomers for electronic materials and optical materials (exo-enriched forms). There is.

As a result of intensive studies in view of such problems, the present inventor has found a method for producing a norbornene compound containing a large amount of exo isomers (exo-enriched), and has completed the present invention.

（式中、Ｒは水素、または置換基を有していてもよいメチル基及びアルキル基もしくはフェニル基のいずれかを表す。）で表わされる２位にアシル基を有するエンド型ノルボルネン化合物（Ａ）に、アセトニトリル中における共役酸の酸解離定数が２０以上の強塩基性有機化合物（Ｂ）を接触させることを特徴とするエキソ型ノルボルネン化合物の製造方法に関する。 That is, the present invention relates to the general formula (1):

(In the formula, R represents hydrogen or an optionally substituted methyl group, alkyl group or phenyl group.) An endo-type norbornene compound having an acyl group at the 2-position (A) And a strongly basic organic compound (B) having an acid dissociation constant of conjugate acid in acetonitrile of 20 or more in contact with the exo-type norbornene compound.

ADVANTAGE OF THE INVENTION According to this invention, the exo-type norbornene compound containing many exo bodies useful as a raw material precursor of monomers for electronic materials and optical materials, especially 2-acyl-5-norbornenes can be provided efficiently.

The present invention relates to an endo-norbornene compound (A) having an acyl group at the 2-position (hereinafter referred to as component (A)), a strongly basic organic compound (B) having an acid dissociation constant of conjugate acid in acetonitrile of 20 or more. (Hereinafter referred to as “component (B)”).
Although the component (A) used for manufacture of this invention is not specifically limited, Usually, General formula (1)

(In the formula, R represents hydrogen or an alkyl group or a phenyl group which may have a substituent). Component (A) is acrolein or vinyl ketones (CH ₂ ═CH—CO—R) (wherein R represents hydrogen or an alkyl group or phenyl group which may have a substituent) by a known method. It is prepared by Diels-Alder reaction of cyclopentadiene.

This epimerization (isomerization) reaction is usually non-aqueous and uses component (B). The acid dissociation constant of the conjugate acid in acetonitrile of component (B) is described in I. Leito et al. Org. Chem. , 70 , 1019 (2005). In the reaction, a solvent may be used. As the solvent, in addition to the primary amines that can react with the component (A) and the compounds and acidic substances that react with the nitrogen of the component (B), other than ordinary hydrocarbon solvents, alcohol solvents, The reaction can also be carried out using an ester solvent, a ketone solvent, a polar organic solvent such as acetonitrile or dimethyl sulfoxide (DMSO).

  Component (B) includes guanidine bases such as tetramethylguanidine and polyguanidine (including guanidine and guanidine derivatives and their substitution products and polyguanides), diazabicyclononene (DBN), diazabicycloundecene (DBU) Amidine-based and guanidine-based polynitrogen polyheterocyclic compounds represented by triazabicyclodecene (TBD), N-methyl-triazabicyclodecene (MTBD), and their polymer-supported strong bases, phosphazene bases And proazaphosphatolan (Verkade) bases. The amount of the component (A) used is suitably about 0.1 to 20 mol%, preferably 0.5 to 10 mol%, relative to the component (A).

  The reaction temperature is generally −60 to 140 ° C., preferably −20 to 100 ° C., more preferably 0 to 80 ° C. If it exceeds 140 ° C., side reactions such as thermal decomposition and thermal polymerization may be complicated as well as thermal isomerization equilibrium, and the yield may decrease.

  The reaction time is usually 1 minute to 24 hours, but can be appropriately changed by adjusting the amount of catalyst and the reaction temperature.

  The exo-type norbornene compound can be obtained by purifying the obtained reaction solution as necessary. The purification method is not particularly limited, but distillation of the reaction solution selectively removes the low-boiling exo-type norbornene compound and leaves the endo-type norbornene compound in the reaction solution system for further epimerization (isomerization). ) It is preferable from the viewpoint that a reaction field capable of continuously performing an equilibrium reaction can be provided.

  The reaction solution may contain the component (B), and distilling the reaction solution while contacting the component (B) selectively takes out the low-boiling exo-type norbornene compound and puts it in the reaction solution system. Is preferable from the viewpoint that an exo-type norbornene compound can be continuously produced since the endo-norbornene compound and the component (B) are left and the epimerization (isomerization) equilibrium reaction is continued.

  The component (A) is distilled as it is without transferring the reaction solution while contacting the component (B), and the component (A) is reacted while it is supplied continuously or divided as needed. The exo-type norbornene compound can be continuously produced by continuing the distillation.

  When basic compounds or acidic compounds such as component (B) or its decomposition products are mixed in the exo-type norbornene compound obtained by the above method, epimerization may occur again, and long-term storage stability It is preferable to remove these compounds by using an adsorbent in order to ensure the reliability.

  As the adsorbent, at least one selected from silica gel, activated alumina, activated carbon, activated clay, ion exchange resin, diatomaceous earth and cellulose can be used. The amount of the adsorbent used is not particularly limited, but is 1 to 100% by weight, preferably 5 to 50% by weight, more preferably 10 to 10% by weight based on the exo-type norbornene compound obtained by distillation purification after epimerization. 25% by weight. The treatment method is not particularly limited. Usually, an adsorbent is added to the obtained exo-type norbornene compound, mixed and stirred for 10 minutes to 120 minutes, and then filtered or purified by distillation after epimerization in a packed column of the adsorbent. An exo form that can be stored for a long time can be obtained through the exo form.

  EXAMPLES Hereinafter, although an Example, a comparative example, an application example, and a storage stability test demonstrate this invention further more concretely, this invention is not limited to these illustrations.

[Example of 2-formyl-5-norbornene (R = H)]
Example 1
A 50 mL four-necked flask equipped with a stirrer, thermometer, and nitrogen inlet was charged with 12.22 g (100 mmol) of endrich 2-formyl-5-norbornene (A), immersed in a constant temperature bath at 25 ° C., and stirred under a nitrogen atmosphere. 0.76 g (5 mmol≈0.75 mL) of diazabicycloundecene (DBU) corresponding to 5 mol% as a strongly basic organic compound (B) with respect to endorich 2-formyl-5-norbornene (A) The epimerization reaction was started by injection. The reaction was monitored using gas chromatography (GC) (apparatus: GC17A manufactured by Shimadzu Corporation; detector: FID; column: using DB5). A part of the reaction solution was sampled at 1, 2, 4 and 24 hours, and the GC analysis results are shown in Table 1. The composition of endorich 2-formyl-5-norbornene (A) was 19.9% exo isomer and 76.9% exo isomer.

Example 2 and Comparative Examples 1-2
The same procedure as in Example 1 was performed except that the base used was changed as shown in Table 1. The results are shown in Table 1.

(In the table, DBU is diazabicycloundecene, 28% NaOMe is a methanol solution containing 28 wt% sodium methoxide, MTBD is N-methyl-triazabicyclodecene, 1Mt-BuOK is 1 mol / l concentration. Represents a t-butanol solution containing potassium t-butoxide.)

  In the epimerization (isomerization) reaction using the strongly basic organic compound (B) shown in Examples 1 and 2 of Table 1, there are few by-products and the epimerization (isomerization) of the endo form into the exo form is the main. In contrast to the reaction, in the reactions using metal alcoholate bases shown in Comparative Examples 1 and 2, an acetal compound or aldol condensate which is a high boiling point compound is obtained as a main product, and the desired epimerization (isomerization) is obtained. It was found that little product was obtained.

Example 3
A 50 mL four-necked flask equipped with a stirrer, thermometer and nitrogen inlet was charged with 12.22 g (100 mmol) of endrich 2-formyl-5-norbornene (A), immersed in a 5 ° C. constant temperature bath, and stirred under a nitrogen atmosphere. To the endrich 2-formyl-5-norbornene (A) was injected 0.58 g (5 mmol≈0.63 mL) of tetramethylguanidine (TMG) corresponding to 5 mol% as a strongly basic organic compound (B). The epimerization reaction was started. After reacting at 5 ° C. for 1 hour, it was reacted at 25 ° C. for 1 hour, 50 ° C. for 2 hours, 70 ° C. for 2 hours, and 100 ° C. for 2 hours. Thereafter, the temperature was raised stepwise to the temperature shown in Table 2, and the reaction was continued for a certain time. The reaction was traced using gas chromatography (apparatus: GC17A manufactured by Shimadzu Corporation; detector: FID; column: using DB5). A part of the reaction solution was sampled every predetermined time, and the results are shown in Table 2. The composition of the raw material (A) was 19.9% exo product and 76.9% endo product. In addition, the numerical value of each column of Table 2 described exo-body / endo-body ratio.

Examples 4-8 and Comparative Examples 3-5
The same procedure as in Example 3 was performed except that the base used was changed from TMG as shown in Table 2. In Example 8, the reaction was completed in 6 hours. The results are shown in Table 2.

(In the table, pKBH ⁺ is an acid dissociation constant, TMG is tetramethylguanidine, DBU is diazabicycloundecene, DBN is diazabicyclononene, PS-BnTBD is N-benzylpolystyrene-supported triazabicyclodecene, MTBD is N- (Methyl-triazabicyclodecene, BTPP represents phosphazene base P1-t-butyl-tris (tetramethylene), Py represents pyridine, and H ⁺ sponge represents proton sponge.)

Strongly basic organic compound (B) having an acid dissociation constant of 20 or more for the conjugate acid determined in acetonitrile from Examples 3 to 8 and Comparative Examples 3 to 5 that were sequentially heated from 5 ° C. to 100 ° C. in Table 2 In Examples 3 to 8 using TMG, DBU, DBN, PS-BnTBS, MTBD, and BTPP, the epimerization (isomerization) reaction proceeds easily, and the exo / endo ratio is about 1.2. On the other hand, it was found that epimerization (isomerization) hardly progressed regardless of the reaction temperature in Comparative Examples 3 to 5 of the uncatalyzed or weakly basic pyridine or proton sponge.

Example 9
A 50 mL four-necked flask equipped with a stirrer, a thermometer, and a nitrogen inlet was charged with 12.22 g (100 mmol) of endrich 2-formyl-5-norbornene (A) and 12.22 g of toluene at a constant temperature of 25 ° C. In a tank, 0.76 g of diazabicycloundecene (DBU) corresponding to 5 mol% as a strongly basic organic compound (B) with respect to endorich 2-formyl-5-norbornene (A) under stirring in a nitrogen atmosphere ( 5 mmol ≒ 0.75 mL) was injected to start the epimerization reaction. After reacting at 25 ° C. for 4 hours, the temperature was raised to 50 ° C. and the reaction was continued for 2 hours. The reaction was traced using gas chromatography (apparatus: GC17A manufactured by Shimadzu Corporation; detector: FID; column: DB5 used). The results after 6 hours of reaction are shown in Table 3. The composition of endorich 2-formyl-5-norbornene (A) was 19.9% exo isomer and 76.9% exo isomer.

Examples 10-17
Except that the solvent used was changed from toluene to chloroform, ethyl acetate, tetrahydrofuran (THF), t-butanol (t-BuOH), cyclohexanone, acetonitrile, dimethyl sulfoxide (DMSO) and no solvent, the same as in Example 9. The results are shown in Table 3.

Example 18
Charged 122.2 g (1 mol) of endrich 2-formyl-5-norbornene (A) to a 300 mL pear type four-necked flask equipped with a thermometer, a nitrogen-introducing capillary tube, and a Witma-rectification column (60 cm, about 5 stages). The flask was purged with nitrogen, then diazabicycloundecene (DBU) 7.6 (0.05 mol) was added under ice-cooling, and the mixture was purged with nitrogen and allowed to stand at room temperature for 1 day. After that, nitrogen bubbling was started under reduced pressure, immersed in an 80 ° C. oil bath and maintained at a reduced pressure of about 70 ° C. and 1000 Pa for 2 hours, then the reduced pressure was increased to 300 to 400 Pa and a fraction having a boiling point of 48 to 52 ° C. Sorted. The distillation results are shown in Table 4.

Example 19
Endrich 2-formyl-5-norbornene (A) 122.2 g (1 mol) was added to a 300 mL pear type four-necked flask equipped with a temperature system, a nitrogen-introducing capillary tube and a Dixon packing packed rectification column (100 cm, about 10 stages). The flask was purged with nitrogen, and diazabicycloundecene (DBU) 7.6 (0.05 mol) was added at room temperature to purge with nitrogen. After that, nitrogen bubbling was started under reduced pressure, immersed in an 80 ° C. oil bath and maintained at a reduced pressure of about 70 ° C. and 1000 Pa for 2 hours, then the reduced pressure was increased to 350 to 400 Pa and the reflux ratio was 10: 1 (return: distillation). The fraction having a boiling point of 49 to 51 ° C. was fractionated by the ratio of the valve opening time. The distillation results are shown in Table 5.

Storage stability test 1
5.0 g of fraction 2 obtained in Example 18 was taken, 5.0 g of toluene and 0.5 g of silica gel were added, and the mixture was stirred for 1 hour. After filtering the silica gel, the toluene was distilled off under reduced pressure and stored at 5 ° C and 25 ° C. The samples sampled every predetermined time were subjected to GC analysis to obtain the exo / endo ratio and the storage stability (epimerization) The presence or absence was examined. The results are shown in Table 6.

Storage stability tests 2-4 and comparative storage stability test 1
It replaced with the silica gel, and it carried out similarly to the storage stability test 1 with the adsorbent untreated as an alumina, activated carbon, activated clay, and a comparative example. The results are shown in Table 6.

Storage stability test 5
10.0 g of fraction 2 obtained in Example 19 was taken, passed through a column packed with 2.0 g of silica gel, stored at 5 ° C. and 25 ° C., and sampled every predetermined time to be subjected to GC analysis and exo / End ratio was determined to determine the presence or absence of storage stability (epimerization). The results are shown in Table 7.

Storage stability test 6-8
It replaced with the silica gel and it carried out similarly to the storage stability test 5 for the adsorption agent using the alumina, activated carbon, and activated clay. The results are shown in Table 7.

From the results of Table 6, it was found that the degree of progress of epimerization was small and stable as compared with the case where any adsorbent was not treated. In particular, the effect of silica gel was remarkable. Further, from the results of Table 7, it was found that the progress of epimerization can be suppressed at a high rate in the case of using any adsorbent for the fraction obtained by increasing the rectification effect by refluxing at a high stage number.

[Example of 2-acetyl-5-norbornene (R = Me)]
Example 20
Into a 50 mL four-necked flask equipped with a stirrer, a thermometer, and a nitrogen inlet, 13.6 g (100 mmol) of endrich 2-acetyl-5-norbornene (A) was charged, immersed in a thermostatic bath at 0 ° C., and placed in a nitrogen atmosphere. Epimerization reaction was initiated by injecting 0.76 g (5 mmol≈0.75 mL) of diazabicycloundecene (DBU) corresponding to 5 mol% as a strongly basic organic compound (B) to (A). After reacting at 0 ° C. for 1 hour (the exo / endo ratio is 0.12), the temperature is raised to 25 ° C. for 1 hour (the exo / endo ratio is 0.12), and the temperature is raised to 50 ° C. for 2 hours ( The exo isomer / endo isomer ratio was 0.17), the temperature was raised to 70 ° C., and the reaction was performed for 2 hours (exo isomer / endo isomer ratio was 0.30) and at 80 ° C. for 6 hours. The reaction was traced using gas chromatography (apparatus: GC17A manufactured by Shimadzu Corporation; detector: FID; column: DB5 used). The results after 12 hours of reaction are shown in Table 8. The composition of the raw material (A) was 10.7% exo-form and 88.5% end-form.

Example 21
The base used was changed from DBU to 0.76 g (5 mmol≈0.71 mL) of N-methyl-triazabicyclodecene (MTBD), and the reaction was allowed to react at 0 ° C. for 1 hour, then warmed to 25 ° C. and heated for 1 hour. The temperature was raised to 50 ° C. for 2 hours, and the temperature was raised to 70 ° C. and reacted for 6 hours. The reaction was performed in the same manner as in Example 20, and the results are shown in Table 8.

Example 22
The base used was changed from DBU to 1.56 g (5 mmol≈1.5 mL) of phosphazene base P1-t-butyl-tris (tetramethylene) (BTPP), and the reaction was carried out at 0 ° C. for 1 hour and then to 25 ° C. The temperature was raised for 1 hour, then raised to 50 ° C. for 2 hours (the exo / endo ratio was 0.24), raised to 70 ° C. for 2 hours, raised to 100 ° C. and reacted for 6 hours. It carried out like Example 20 and the result was shown in Table 8.

Example 23
The reaction was carried out in the same manner as in Example 20 except that the reaction temperature was kept constant at 50 ° C. for 48 hours, and the results are shown in Table 8.

Example 24
The reaction was carried out in the same manner as in Example 20 except that the reaction temperature was kept constant at 80 ° C. for 24 hours, and the results are shown in Table 8.

(In the table, DBU represents diazabicycloundecene, MTBD represents N-methyl-triazabicyclodecene, and BTPP represents phosphazene base P1-t-butyl-tris (tetramethylene).)

[Example of 2-benzoyl-5-norbornene (R = Ph)]
Example 25
Into a 50 mL four-necked flask equipped with a stirrer, a thermometer, and a nitrogen inlet, 19.8 g (100 mmol) of endrich 2-benzoyl-5-norbornene (A) was charged, immersed in a thermostatic bath at 0 ° C., and placed in a nitrogen atmosphere. Into endrich 2-benzoyl-5-norbornene (A), 0.76 g (5 mmol≈0.75 mL) of diazabicycloundecene (DBU) corresponding to 5 mol% was injected as a strongly basic organic compound (B). Then, the epimerization reaction was started. After reacting at 0 ° C. for 1 hour, the temperature was raised to 25 ° C. for 1 hour, raised to 50 ° C., raised for 2 hours, raised to 70 ° C., and reacted at 80 ° C. for 5 hours. The reaction was traced using gas chromatography (apparatus: GC17A manufactured by Shimadzu Corporation; detector: FID; column: DB5 used). The results are shown in Table 9. The composition of endorich 2-benzoyl-5-norbornene (A) was 47.0% exo isomer and 50.5% endo isomer.

Example 26
The reaction was carried out in the same manner as in Example 25 except that the reaction temperature was kept constant at 50 ° C. for 24 hours, and the results of GC analysis are shown in Table 9.

Example 27
The reaction was performed in the same manner as in Example 25 except that the reaction temperature was kept constant at 80 ° C. for 12 hours. The results of GC analysis are shown in Table 9.

The method for producing 2-acyl-5-norbornenes containing a large amount of exo isomers according to the present invention is useful as a method for efficiently producing alicyclic polymers for electronic materials and optical materials.

Claims (8)

General formula (1):

(In the formula, R represents hydrogen or an optionally substituted methyl group, alkyl group or phenyl group.) An endo-type norbornene compound having an acyl group at the 2-position (A) And a strongly basic organic compound (B) having an acid dissociation constant of the conjugate acid in acetonitrile of 20 or more is contacted with the process for producing an exo-type norbornene compound. A strongly basic organic compound (B) having an acid dissociation constant of 20 or more for a conjugate acid obtained in acetonitrile is a strong base of guanidine bases, amidine-based and guanidine-based polynitrogen polyheterocyclic compounds, and a polymer support thereof. The method for producing an exo-type norbornene compound according to claim 1 , wherein the exo-norbornene compound is at least one selected from the group consisting of strong bases, phosphazene bases, and proazaphosphatran bases. A reaction solution obtained by contacting an endo-norbornene compound (A) having an acyl group at the 2-position with a strongly basic organic compound (B) having an acid dissociation constant of a conjugate acid of 20 or more determined in acetonitrile. The method for producing an exo-type norbornene compound according to claim 1 or 2 , wherein the exo-type norbornene compound is obtained by distillation. Distilling the reaction solution while contacting an endo-type norbornene compound (A) having an acyl group at the 2-position with a strongly basic organic compound (B) having an acid dissociation constant of the conjugate acid determined in acetonitrile of 20 or more. The exo-type norbornene compound according to any one of claims 1 to 3 , wherein the exo-type norbornene compound is obtained by the method. While the endo-norbornene compound (A) having an acyl group at the 2-position is brought into contact with a strongly basic organic compound (B) having an acid dissociation constant of conjugate acid of 20 or more obtained in acetonitrile, the reaction solution is distilled. to any one of claims 1 to 4, characterized in that to obtain the exo-type norbornene compound by continuing continuous or divided and distillation reaction while additionally supplied ended norbornene compound having a 2-position acyl group The manufacturing method of exo-type norbornene compound of description. While the endo-norbornene compound (A) having an acyl group at the 2-position is brought into contact with a strongly basic organic compound (B) having an acid dissociation constant of conjugate acid of 20 or more obtained in acetonitrile, the reaction solution is distilled. An exo-type norbornene compound by continuing the reaction and distillation while supplying the endo-type norbornene compound (A) having an acyl group at the 2-position and the strongly basic organic compound (B) simultaneously or separately continuously or separately. The method for producing an exo-type norbornene compound according to any one of claims 1 to 4, wherein: The method for producing an exo-type norbornene compound according to claim 3 , wherein an exo-type norbornene compound obtained by distillation is brought into contact with an adsorbent. The method for producing an exo-type norbornene compound according to claim 7 , wherein the adsorbent is at least one selected from the group consisting of silica gel, activated alumina, activated carbon, activated clay, ion exchange resin, diatomaceous earth, and cellulose.