JPH0772165B2 - 2,5-Substituted-cyclohexane-1,4-bis (dicyanomethylene) and method for producing the same - Google Patents

Description

TECHNICAL FIELD The present invention relates to a novel compound useful as an intermediate for a tetracyanoquinodimethane derivative, which can be expected to be used as a raw material for producing polyester, polyamide, polyurethane, etc., or as an organic semiconductor. It is a thing.

Conventional technology 7,7,8,8-Tetracyanoquinodimethane (TCNQ) has a melting point of 29
It is a yellow crystal of 3.5-296 ° C. This compound easily accepts one electron to form a stable anion radical,
The derivative exhibits extremely low electrical resistance. This compound is reduced with thiophenol, mercaptoacetic acid, hydrogen iodide and the like to phenylenedimalononitrile, which is oxidized to N-bromosuccinimide and returns to TCNQ again. A practical application of TCNQ is a chemical capacitor.

Examples of the synthesis method of TCNQ include malononitrile and 1,4
-1,4- obtained by condensing cyclohexane-dione
It is known to oxidize bis- (dicyanomethylene) cyclohexane in pyridine with N-bromosuccinimide or bromine.

Problems to be Solved by the Invention As described above, TCNQ has conductivity even though it is an organic compound. Therefore, a synthetic method by another route of the compound is found, or a compound having a skeleton similar to the compound has conductivity. Finding is important for research, development, and practical application of this type of organic conductive compound.

An object of the present invention is to provide a novel compound useful as a raw material for producing polyester, polyamide, polyurethane or the like, or as an intermediate of a TCNQ derivative which can be expected to be used as an organic semiconductor.

Means for Solving the Problems The compounds of the present invention are represented by the following general formula: 2,5-substituted-
Cyclohexane-1,4-bis (dicyanomethylene), which is a novel compound not yet published in the literature.

In the formula, R ¹ is hydrogen or a methyl group, X is COOR ² (R ² is hydrogen or an alkyl group) or CN. However, when R ¹ is hydrogen, X is CN.

When R ² is an alkyl group, examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, an octyl group, a decyl group, a cyclohexyl group, and the like.
An alkyl group having about 10 carbon atoms, particularly a lower alkyl group having 1 to 4 carbon atoms can be mentioned.

Specific examples of the compound (IV) are those in which R ¹ is hydrogen and X is CN, that is, 2,5-
Bis (2-cyanoethyl) -cyclohexane-1,4-bis (dicyanomethylene), wherein R ¹ is a methyl group and X is COOR ² , that is, 2,5-bis [2- (alkoxycarbonyl) propyl] -Cyclohexane-1,4-bis (dicyanomethylene) or 2,5-bis [2- (carboxy) propyl]
-Cyclohexane-1,4-bis (dicyanomethylene), wherein R ¹ is a methyl group and X is CN, that is, 2,
5-bis [2- (cyano) propyl] -cyclohexane-1,4-bis (dicyanomethylene), and the like.

Next, a method for producing the compound of the present invention represented by the above formula (IV) will be described.

Compound (IV) has the general formula [Wherein R ¹ , X and R ² are the same as above]
Substituted - cyclohexane-1,4-dione, it is prepared by reacting a malonitrile of the formula NC-CH ₂ -CN.

The reaction is usually performed in a solvent such as water, alcohol or water / alcohol.

In the reaction, a small amount of a catalyst such as β-alanine, glycine and ammonium acetate is allowed to coexist.

When X is COOH, if necessary, the compound (III) is previously prepared.
Is preferably neutralized with sodium hydrogen carbonate or other alkaline substance.

It is sufficient to carry out the reaction under heating (for example, 40 to 60 ° C.) for about 1 to 5 hours.

The molar ratio of compound (III) and malononitrile used is usually 1 mol of the former and 2 mol of the latter,
It does not matter if the latter is used in excess.

After completion of the reaction, the precipitated crystals may be collected and purified by a conventional method.

A compound in which X is COOR ² and R ² is an alkyl group (I
V) is obtained by using a compound (III) in which R ² is an alkyl group as a reaction raw material, and a compound (III) in which X is COOH is used during the reaction with malononitrile. It is also possible to carry out the esterification or to carry out the esterification after this reaction. When the esterification is simultaneously carried out during the reaction, this reaction may be carried out in the presence of alcohol. When the reaction product, compound (IV), is esterified after the reaction is completed, the reaction product is treated with thionyl chloride or the like. After forming the acid chloride, it may be reacted with alcohol.

The compound (IV) thus obtained is treated with bromine or N-
Oxidation with bromosuccinimide gives the general formula 2,5-substituted-7,7,8,8-tetracyanoquinodimethane represented by

Compound (III), which is a starting material, can be produced according to the following formula.

In the first step reaction, compound (I), that is, cyclohexane-1,4-dione is enamined with pyrrolidine to obtain compound (II), that is, 1,4-dipyrrolidinocyclohexane-1,3-diene. It is a reaction.

As the solvent, benzene, toluene, xylene or the like is used.

The reaction temperature is preferably under reflux, and the reaction proceeds while removing by-product water during the reaction from the system. A catalyst is not particularly required, but an acid such as p-toluenesulfonic acid can be used.

The reaction system prevents oxidation of the generated dienamine,
It is advantageous to keep it under a nitrogen atmosphere.

The amount of pyrrolidine used is 2 with respect to 1 mol of the compound (I).
Is selected from the range of 4 mol.

The reaction time is suitably 1 to 3 hours.

After removing the solvent and the residual pyrrolidine from the reaction product solution of the first step reaction, the reaction with the unsaturated compound, which is the second step reaction, is carried out.

As the solvent, dioxane, dimethylformamide, ethanol, methanol, acetonitrile or the like is used.

The unsaturated compound is used in the proportion of 2 to 4 mol per 1 mol of the compound (I).

The reaction is performed under reflux for about 3 to 24 hours, and then about 2 molar equivalents of water are added to cyclohexanedione to add 1 to
When the hydrolysis reaction is continued under reflux for about 2 hours, the desired product is obtained.

Specific examples of unsaturated compounds include methacrylic acid, alkyl methacrylates (methyl methacrylate, ethyl methacrylate, etc.), acrylonitrile, methacrylonitrile, and the like.

The compound (IV) of the present invention can be expected to have various uses,
For example, it is useful as a raw material for producing polyester, polyamide, polyurethane or the like, or as an intermediate for producing a tetracyanoquinodimethane (TCNQ) derivative as an organic semiconductor.

Action As described above, when the compound (IV) of the present invention is oxidized with an oxidizing agent such as bromine or N-bromosuccinimide, the compound (V), that is, 2,5-substituted-7,7 , 8,8
-Tetracyanoquinodimethane can be obtained.

The series of reactions detailed above is summarized as follows. Compound (IV) corresponds to the compound of the present invention, and the reaction of corresponds to the method of the present invention.

The compound (III) itself is also a novel compound, and the reaction of and to obtain the compound (III) is also a novel method. Therefore, the applicant has already filed a patent application 61
-The patent application was filed as No. 208276.

Furthermore, the compound (V) is also a novel compound, and the reaction for obtaining the compound (V) is also a novel method. Therefore, the present applicant also filed a separate patent application in parallel with the patent application for the present invention.

EXAMPLES Next, the present invention will be further described with reference to examples.

Example 1 This example illustrates 2, as an example of compound (IV) of the present invention.
5-bis (2-cyanoethyl) -cyclohexane-1,4-
It is related to bis (dicyanomethylene). Hereinafter, this compound will be abbreviated as (IVa).

The compound (IVa) is 2,5-bis (2-cyanoethyl)-
It is obtained by reacting cyclohexane-1,4-dione (hereinafter abbreviated as (IIIa)) with malononitrile.

Preparation of compound (IIIa) Cyclohexane-1,4-dione 11.2 g (0.1 mol), pyrrolidine 21.3 g (0.3 mol) and toluene 45 ml were mixed,
The mixture was allowed to react for 3 hours under reflux while introducing nitrogen gas.

Toluene and residual pyrrolidine were removed and dioxane was removed.
50 ml and 15.9 g (0.3 mol) of acrylonitrile were charged and reacted under reflux for 12 hours. Subsequently, 5 ml of water was added, and the reaction was continued under reflux for 1 hour.

After completion of the reaction, the residual acrylonitrile and dioxane were removed from the reaction solution, 300 ml of water was added, and the mixture was extracted with chloroform.

The chloroform layer was washed with 10% hydrochloric acid, further washed with water, and then dehydrated with sodium sulfate. Chloroform was distilled off from the extract to obtain 10.9 g of crystals, which was then recrystallized from methanol to give colorless crystals having a melting point of 147.8 ° C.

This crystal has NMR spectrum, mass spectrum and IR
As a result of the spectrum analysis, the compound (IIIa), that is, 2,
5-bis (2-cyanoethyl) -cyclohexane-1,4-
It was identified to be a dione.

Production of compound (IVa) 873 mg of compound (IIIa) obtained above, 3.4 g of water, methanol
5.0 g and β-alanine 9.9 mg were mixed and warmed. At the time when the internal temperature reached 45 ° C, a solution prepared by dissolving 536 mg of malononitrile in 1.6 g of methanol was charged in advance at a time,
The reaction was carried out at ℃ for 1.5 hours.

After completion of the reaction, the mixture was cooled to room temperature, the crystals were separated by filtration, washed with water and washed with methanol, and then dried under reduced pressure to obtain 1.24 g of crystals.

The obtained crystals have the following characteristic values, and the compound (IVa),
That is, it was confirmed to be 2,5-bis (2-cyanoethyl) -cyclohexane-1,4-bis (dicyanomethylene). The yield based on the compound (IIIa) was 98.6%.
Met.

Example 2 In this example, as an example of the compound (IV) of the present invention,
2,5-bis [2- (methoxycarbonyl) propyl]-
It is related to cyclohexane-1,4-bis (dicyanomethylene). Hereinafter, this compound will be abbreviated as (IVb).

The compound (IVb) can be obtained by reacting 2,5-bis [2- (methoxycarbonyl) propyl] -cyclohexane-1,4-dione (hereinafter abbreviated as (IIIb)) with malononitrile.

Preparation of compound (IIIb) Cyclohexane-1,4-dione 11.2 g (0.1 mol), pyrrolidine 21.3 g (0.3 mol) and benzene 45 ml were mixed,
The mixture was allowed to react for 3 hours under reflux while introducing nitrogen gas.

Remove benzene and residual pyrrolidine, and remove ethanol
Charge 50 ml and methyl methacrylate 30.3 (0.3 mol),
The reaction was carried out under reflux for 12 hours. Subsequently, 10 ml of water was added and hydrolysis was carried out for 1 hour under reflux.

After the reaction was completed, ethanol and excess methyl methacrylate were removed, 300 ml of water was added, and the mixture was extracted with chloroform. Next, after washing with 10% hydrochloric acid to remove chloroform from the chloroform layer, a colorless viscous oil was obtained using a Kugel vacuum distillation apparatus at an oven temperature of 190 to 210 ° C (1.0 to 1.2 mmHg).

This oil contains NMR spectrum, mass spectrum and
As a result of R spectrum analysis, the compound (IIIb), that is,
2,5-bis [2- (methoxycarbonyl) propyl]-
It was identified to be cyclohexane-1,4-dione.

Production of compound (IVb) 1.0 g of compound (IIIb) obtained above, 3.5 g of water, methanol 2.
0 g and β-alanine 8 mg were mixed and warmed. Inner temperature is 4
When the temperature reached 5 ° C, a solution prepared by dissolving 432 mg of malononitrile in 1.6 g of methanol was batch-charged at 45-52 ° C.
The reaction was carried out for 1.5 hours.

After completion of the reaction, the mixture was cooled to room temperature, the oil layer was separated, ether was added for crystallization, the crystals were separated by filtration, washed with ether, and dried under reduced pressure to give 0.40 g.
Was obtained.

The obtained crystals have the following characteristic values, and the compound (IVb),
That is, it was confirmed to be 2,5-bis [2- (methoxycarbonyl) propyl] -cyclohexane-1,4-bis (dicyanomethylene). The yield based on the compound (IIIb) was 30.6%.

Example 3 2,5-bis [2- (cyano) propyl] -cyclohexane-1,4-dione (compound (IIIc)) was prepared in the same manner as in Example 1 except that methacrylonitrile was used instead of acrylonitrile. Obtained.

When the compound (IIIc) was reacted with malononitrile in the same manner as in Example 1, 2,5-bis [2- (cyano) propyl] -cyclohexane-1,4-bis (dicyanomethylene) compound (IVc)) was obtained. Was confirmed to have been generated.

EFFECTS OF THE INVENTION Since the present invention can provide a novel compound, 2,5-substituted-cyclohexane-1,4-bis (dicyanomethylene), it can be used as a raw material for producing polyester, polyamide, polyurethane or the like, or tetracyano as an organic semiconductor. The route for obtaining intermediates of quinodimethane (TCNQ) derivatives is expanded.

Claims (5)

[Claims] 1. A general formula [Wherein R ¹ is hydrogen or a methyl group, X is COOR ² (R ² is hydrogen or an alkyl group) or CN, provided that when R ¹ is hydrogen, X is CN]. Cyclohexane-1,4
-Bis (dicyanomethylene). 2. The compound according to claim 1, which is 2,5-bis (2-cyanoethyl) -cyclohexane-1,4-bis (dicyanomethylene). 3. 5-5-Bis [2- (alkoxycarbonyl) propyl] -cyclohexane-1,4-bis (dicyanomethylene) or 2,5-bis [2- (carboxy) propyl] -cyclohexane-1, A compound according to claim 1 which is 4-bis (dicyanomethylene). 4. A 2,5-bis [2- (cyano) propyl]-
The compound of claim 1 which is cyclohexane-1,4-bis (dicyanomethylene). 5. A general formula [Wherein R ¹ is hydrogen or a methyl group, X is COOR ² (R ² is hydrogen or an alkyl group) or CN, provided that when R ¹ is hydrogen, X is CN]. Cyclohexane-1,4
- formula, wherein the dione, reacting an malononitrile represented by the formula NC-CH ₂ -CN [Wherein R ¹ , X and R ² are the same as above]
A process for producing substituted-cyclohexane-1,4-bis (dicyanomethylene).