JPH0244310B2 - MONOMATAHAJECHINIRUCHIOFUENNOSEIZOHO - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing mono- or diethynylthiophene. Conventionally, the method of introducing one ethynyl group (-C≡CH) into a heteroaromatic ring compound such as thiophene is as follows:
Two or three types are known, but each method requires a large number of synthesis steps and the yield of the target product is low, making synthesis difficult. Furthermore, dienylthiophene having two ethynyl groups was not known. However, recently,

[Formula] (X is a halogen) 2,5-dihalogenothiophene is catalyzed by a palladium compound and a copper compound in the presence of an amine to prepare RR′R″SiC≡CH (R, R′ and R'' is the same or different and is an alkyl group, an aryl group, or an alkenyl group. A method for synthesizing and isolating diethynylthiophene into which
57-144284). The method using this silylacetylene compound is
Although it is a useful method for introducing an ethynyl group into a thiophene ring without side reactions, it is not easy to synthesize the raw material silylacetylene compound, and specifically, it requires handling acetylene gas at high temperatures for a long time. The disadvantages were that it required a large number of synthesis steps, required a large number of synthesis steps, and had a low yield. Under such circumstances, the present inventors have conducted intensive research and have discovered an effective method for producing monoethynylthiophene or diethynylthiophene, and have completed the present invention. An object of the present invention is to provide a new method that can advantageously produce monoethynylthiophene or diethynylthiophene through simple steps. In the present invention, the structural formula

Monohalogenothiophene or structural formula represented by [Formula] (X is halogen) etc.

[Formula] (X is a halogen atom) etc. dihalogenothiophene is mixed with the formula Pd(PR ³ ₃ ) ₄ or Pd(MR ³ ₃ ) ₂ X ₂ (wherein, M is P, As or N
, R ³ represents an alkyl group, phenyl group or aralkyl group, and X represents a halogen atom. )
Using a specific palladium compound and a monovalent copper compound represented by as catalysts, react with a specific alcohol having an ethynyl group represented by the following general formula,
Mono- or diethynyl offene is produced by deketonizing this reaction product with a specific basic substance selected from alkali metals, alkali metal hydroxides, alkali metal alkoxides, and alkyl alkali metals. general formula (In the formula, R ¹ and R ² are an alkyl group, an aryl group, or an alkenyl group, and R ¹ and R ² may be the same or different.) The monohalogenothiophene used in the present invention is Examples include chlorothiophene, bromothiophene, iodothiophene, and the like. Among these, bromothiophene is preferred. These monohalogenothiophenes yield monoethynylthiophenes. Examples of dihalogenothiophene include dichlorothiophene, dibromothiophene, and diiodothiophene. Among these, dibromothiophene is preferred. These dihalogenothiophenes yield diethynylthiophenes. The specific alcohol having an ethynyl group is
It is represented by the above general formula. In the above general formula, R ¹ and R ² are ^an alkyl group such as a methyl group, an ethyl group, or a propyl group, an aryl group such as a phenyl group, or an alkenyl group such as a vinyl group or an ^{isopropenyl group} ; They may be the same or different. Preferred R ¹ and R ² in this case are:
From the viewpoint of ease of deketonization reaction and ease of industrial availability, a methyl group is preferred. The amount of the above-mentioned specific ethynyl alcohol having an ethynyl group is 1.0 to 1.5 mol per mol of monohalogenothiophene, and 2.0 to 1.5 mol per mol of halogenothiophene. Preferably, it is 3.0 mol. Examples of palladium compounds used as catalysts include Pd(PR ³ ₃ ) ₄ (R ³ represents an alkyl group, phenyl group, or aralkyl group. The same applies hereinafter), Pd(PR ³ ₃ ) ₂ X ₂ (X indicates a halogen atom.
The same applies below. However, the halogen atom does not need to be the same as the monohalogenothiophene or dihalogenothiophene. ), Pd
Compounds represented _{by (} AsR ³ _{3 ) 2 X 2 and Pd (NR 3} ³ _{) 2}
(Ph represents a phenyl group. The same applies below.)
Pd( _PPh3 ) _{2Cl2 is} preferred. The amount of the palladium compound used is preferably 0.005 to 0.05 mol per 1 mol of monohalogenothiophene, and 0.01 to 0.05 mol per 1 mol of dihalogenothiophene. . Copper compounds used as catalysts include:
Monovalent copper compounds such as CuCl, CuI, CuBr, Cu ₂ O, and CuCN can be suitably used;
CuBr and CuCl are preferred. The amount of this copper compound to be used is 0.001 to 0.01 mol per 1 mol of monohalogenothiophene, and 0.001 to 0.01 mol per 1 mol of dihalogenothiophene.
The amount is preferably 0.005 to 0.05 mol. In the present invention, the amine acts as a dehalogenating agent, specifically, for example, methylamine, ethylamine, hexylamine, aniline,
Primary amines such as benzylamine, dimethylamine, diethylamine, methylethylamine, N-
Secondary amines such as methylaniline and piperidine, trimethylamine, triethylamine, N,N-dimethylaniline, benzyldimethylamine, N,
Any amine that forms ammonium halide can be used, such as a tertiary amine such as N,N',N'-tetramethylethylenediamine. The amount of amine used is usually 5 mol or more, preferably 5 to 1 mol, per 1 mol of monohalogenothiophene or dihalogenothiophene.
It is 1000 moles. If the amount of amine used is too small, dehalogenation will be insufficient, which is not preferable. Although amines also act as solvents, other solvents may be used together with amines. In this case, solvents include hydrocarbons such as hexane and benzene, halogenated hydrocarbons such as dichloromethane and chloroform, and diethyl ether. , and ethers such as tetrahydrofuran. Deketonization is carried out using basic substances, but
These basic substances include alkali metals such as Li and Na, alkali metal hydroxides such as NaOH and KOH,
Alkali metal alkoxides such as NaOCH ₃ and NaOC ₂ H ₅ and alkali alkali metals such as n-C ₄ H ₉ Li can be used; among these, NaOH,
KOH is preferred. This basic substance is preferably 0.1 to 1 mol per mole of thienylalkynol or thienyl dialkynol, which is an intermediate product.
Use moles. Next, an example of the manufacturing method of the present invention will be shown. First, a monohalogenothiophene and a specific alcohol having an ethynyl group are dissolved in a solvent containing an amine, which is a dehalogenating agent, and a palladium compound and a copper compound, which are catalysts, are added thereto, and the mixture is stirred and reacted. The reaction temperature is preferably 15-70℃, and the reaction time is
10 to 20 hours is appropriate. Although the reaction atmosphere is not particularly limited, it is preferable to carry out the reaction under an inert gas atmosphere such as nitrogen. This reaction produces intermediate products such as thiophene derivatives, e.g.

[Formula] and ammonium halide are produced. After completion of the reaction, the ammonium halide was removed by washing with water, the reaction mixture was extracted with ether, and low boilers were distilled off under reduced pressure.
The residue is then purified by vacuum distillation to produce an intermediate product, thiophene derivative, e.g., when R ¹ and R ² are methyl groups, pale yellow crystals of 4-thienyl-2-
Methyl-3-butyn-2-ol is obtained. The intermediate thiophene derivatives thus obtained, e.g.

[Formula] is reacted with a basic substance such as an alkali metal hydroxide in an organic solvent to perform deketonization, insoluble solids are separated, and the liquid is concentrated. Any organic solvent can be used as long as it can dissolve thiophene derivatives, which are intermediate products such as hydrocarbons, ethers, amines, aldehydes, sulfoxides, alcohols, and esters. The reaction temperature for this deketonization reaction is usually 50 to 150°C, and the reaction time is 1
~5 hours is appropriate. Although the reaction atmosphere is not particularly limited, this reaction is preferably carried out under an atmosphere of an inert gas such as nitrogen. Monoethynylthiophene is obtained by purifying the reaction product obtained by this reaction. Furthermore, in the above operation, if dihalogenothiophene is used instead of monohalogenothiophene, diethynylthiophene can be obtained. By polymerizing monoethynylthiophene as a starting monomer, a polyacetylene derivative having a thiophene ring can be obtained. Furthermore, in the present invention, diethynylthiophene obtained when dihalogenothiophene is used,
By performing an oxidative coupling reaction using this as a starting monomer, poly(diethynylthiophene)

[Formula] can be easily obtained. This poly(diethynylthiophene) has better heat resistance than poly(diethynylbenzene), which has a similar structure. In other words, poly(diethynylbenzene) decomposes thermally at temperatures below 200°C (J.Polym.Sci.
A-1 Vol. 7, p. 1625 (1969)), poly(diethynylthiophene) does not undergo thermal decomposition even at a temperature of 300°C and is stable. Furthermore

[Formula] (R ⁴ represents a thiophene ring or a pyridine ring) type polymer is insoluble in organic solvents (Polymer Preprints Japan
30, No. 1, p. 160 (1981)), poly(diethynylthiophene) is soluble in organic solvents, so it can be easily molded using casting molding, etc. . These linear conjugated polymers can be produced with various conductivities (e.g., 10 ^-2 Ω ^-1 cm ^{- 1} ) It can be used as an organic semiconductor material or an organic conductive material. As mentioned above, both monoethynylthiophene and diethynylthiophene are organic semiconductor materials,
It can be used as a starting material to give polymers useful as organic conductive materials. Next, the present invention will be explained in more detail with reference to Examples. Example 1 Under a nitrogen atmosphere, 50 g (0.31 mol) of 2-bromothiophene and 31 g (0.37 mol) of 2-methyl-3 were placed in a three-necked flask equipped with a reflux condenser.
-Butyn-2-ol and 600 ml of diethylamine are added and stirred. Add to this 2.2 g (3.1 mmol) of dichlorobis(triphenylphosphine)
Add palladium and 0.30 g (1.6 mmol) of cuprous iodide and stir well to react at room temperature for 15 hours. After the reaction is complete, the reaction mixture is concentrated under reduced pressure, the residue is washed with water to remove ammonium halide, and then extracted with ether. The ether was distilled off under reduced pressure, and the residue was distilled under reduced pressure to give pale yellow crystals.
46.0g (yield 90%) was obtained. The melting point of this crystal is 55-57℃, the boiling point is 112℃/2mmHg, and
NMR spectrum (δ value in _CCl4 ) data shows _CH3 proton (1.61, singlet, 6H), OH proton (3.33, singlet, 1H),

[Formula] The existence of protons (7.19, multiplet, 3H), IR spectrum (Nujol mulls) data, ν(OH) (3230cm ^-1 ), ν(C≡C)
(2220 cm ^-1 ) and a thiophene ring (825 cm ^-1 ), it was determined to be 4-(2-thienyl)-2-methyl-3-butyn-2-ol having the following structure. Subsequently, 8.0 g (48 mmol) of 4-(2-thienyl)-2-methyl-3-butyn-2-ol thus obtained and 130 ml of toluene were charged into a 300 ml three-necked flask under a nitrogen stream. 1.0g for this
(25 mmol) of sodium hydroxide, NaOH, is added by grinding and refluxed for 2 hours. After the reaction was completed, the solid was separated, the liquid was concentrated under reduced pressure, and the residue was distilled under reduced pressure to obtain 2.6 g (yield: 50%) of a colorless oil.
The boiling point of this oil is 50-51℃/21mmHg,
Also, from the NMR spectrum (δ value in CDCl ₃ ) data, C≡CH proton (3.10, singlet, 1H),

[Formula] The existence of protons (6.80, multiplet, 3H), IR spectrum (Neat) data, ν(C≡CH)(3280cm ^-1 ), ν(C≡C)(2100
cm ^-1 ), 2-thienylthiophene due to the presence of a thiophene ring (820 cm ^-1 )

[Formula] was decided. Example 2 Under nitrogen flow, 500ml 3 tube equipped with reflux condenser
In a neck flask, add 25 g (103 mmol) of 2.5
- dibromothiophene, 10.4 g (124 mmol)
2-methyl-3-butyn-2-ol and 250
ml of diethylamine and stir. to this
Add 1.45 g (2.1 mmol) of dichlorobis(triphenylphosphine)palladium and 0.20 g (1.0 mmol) of cuprous iodide, and stir for 15 hours at room temperature to react. After the reaction is complete, insoluble diethylammonium bromide is separated, the liquid is concentrated under reduced pressure, and the residue is extracted with ether. The ether solution was concentrated under reduced pressure, and petroleum ether was added to solidify the oil to obtain 20.6 g of light brown powder (80% yield). The melting point of this light brown powder is 118-120°C, and from the NMR spectrum (δ value in acetone- _d6 ) data, CH ₃ proton (1.49, singlet, 12H), OH proton (4.40, singlet, 2H),

[Formula] The existence of (7.03, singlet, 2H), IR spectrum (Nujolmulls) data, ν(OH) (3310cm ^-1 ), ν(C≡C)
(2220 cm ^-1 ), thiophene ring (810 cm ^-1 ), 2.5-bis(3-methyl=3-hydroxy-2-butynyl)thiophene It was decided. Next, 5.0g (20.2 mmol) obtained in this way
2,5-bis(3-methyl-3-hydroxy-
2-Butynyl) thiophene and 120 ml of toluene are placed in a 300 ml three-necked flask under nitrogen flow. Add 0.80 g (14.3 mmol) of potassium hydroxide to this
KOH is crushed and added, and nitrogen is blown into the mixture at a temperature of 65° C. for 3 hours to remove by-product ketones. After the reaction, the solid was separated, the liquid toluene was distilled off under reduced pressure, and the residue was distilled under reduced pressure to obtain 2.45 g of pale yellow oil.
(yield 92%). The boiling point of this oil is 40℃/
0.1 mmHg, and the NMR spectrum (CDCl ₃
From the data, C≡CH proton (3.37,
Single line, 2H),

[Formula] (7.23, singlet, 2H) exists, and from the IR spectrum (Neat) data, ν(C≡CH) (3280cm ^-1 ),
ν(C≡C) (2100cm ^-1 ), thiophene ring (800cm
^-1 ), 2,5-diethynylthiophene

[Formula] was decided.

Claims (1)

[Scope of Claims] 1. Monohalogenothiophene or dihalogenothiophene in the presence of an amine with the formula Pd(PR ³ ₃ ) ₄ or Pd(MR ³ ₃ ) ₂ X ₂ (wherein M is P, As or N, R ³ represents an alkyl group, phenyl group, or aralkyl group, and X represents a halogen atom. mono- or diethynyl, characterized in that it is reacted with an alcohol having a group, and the reaction product is deketonized with a basic substance selected from alkali metals, alkali metal hydroxides, alkali metal alkoxides, and alkyl alkali metals. Method for producing thiophene. general formula (In the formula, R ¹ and R ² are an alkyl group, an aryl group, or an alkenyl group, and R ¹ and R ² may be the same or different.)