JP2015163601A - High-purity dihalogenobenzobisthiadiazole compound and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dihalogenobenzobisthiazole compound that has a sufficiently high purity as to be usable as a synthetic intermediate of an organic semiconductor material and a method of producing the same.SOLUTION: Provided are a high-purity dihalogenobenzobisthiadiazole compound of formula (1) which has a sulfur content of 1 wt% or less and a method for producing the high-purity dihalogenobenzobisthiadiazole compound. A tetraaminobenzene compound (including a base) and a halogenating agent are reacted in a halogenated hydrocarbon solvent in the presence of a base to produce a crude dihalogenobenzobisthiazole compound and subjecting the resultant compound and a halogenated hydrocarbon is subjected to contact treatment to produce a high-purity dihalogenobenzobisthiazole.

Description

  The present invention relates to a highly pure dihalogenobenzobisthiadiazole compound having a reduced sulfur content. A dihalogenobenzobisthiadiazole compound is a useful compound as a raw material for producing various organic semiconductor materials, for example.

  Conventionally, as a method for producing a dihalogenobenzobisthiadiazole compound, for example, 1,2,4,5-tetraaminobenzene tetrahydrobromide is reacted with thionyl bromide to yield 4,8 at a yield of 87%. -A method for producing dibromobenzobisthiadiazole is disclosed (for example, see Non-Patent Document 1).

In addition, after reacting 2,5-dibromo-3,4-diaminebenzothiazole and thionyl chloride, the obtained solid was washed with water and methanol, and the crude product was sublimated at 200 ° C. and 10 ⁻⁶ Torr. A method for purification to obtain 4,8-dibromobenzobisthiadiazole with a yield of 74% is disclosed (for example, see Non-Patent Document 2).

  It is also known that 4,8-dibromobenzobisthiadiazole is suitably used as an intermediate for useful organic semiconductor materials (see, for example, Patent Document 1).

Organic Lett. , Vol. 12, no. 15, p. 3340 (2010) Tetrahedron, Vol. 53, no. 29, p. 10169 (1997)

International Publication No. 2013/141182

  However, when the present inventors conducted a follow-up experiment on the method of Non-Patent Document 1, the reaction between the following 4,8-dibromobenzobisthiadiazole and tri (n-butyl) (thienyl) tin almost progressed. (See Comparative Examples 1 and 2 described later).

  In Non-Patent Document 2, sublimation / purification must be performed under severe conditions (sublimation temperature is 200 ° C. with respect to decomposition temperature of 260 ° C.). There wasn't. Furthermore, this processing method has a problem that low boiling point components and volatile components are accompanied by sublimation.

  Furthermore, in Non-Patent Documents 1 and 2, no attention is paid to impurities in the dihalogenobenzobisthiadiazole compound, and no mention is made of its purity, purification method, analysis method, or the like.

  An object of the present invention is to provide a dihalogenobenzobisthiadiazole compound having a sufficiently high purity that can be used as a synthetic intermediate of an organic semiconductor material by an industrially suitable production method, and a production method thereof.

  The subject of this invention is general formula (1) whose sulfur content measured by the following measuring method is 1 weight% or less.

(In the formula, X represents a halogen atom.)
It is solved by a high-purity dihalogenobenzobisthiadiazole compound represented by

  However, the case where the sulfur content is 0% by weight is excluded.

Sulfur measurement method;
A dihalogenobenzobisthiadiazole compound and 1,2-dichlorobenzene are mixed and dissolved by heating, and then cooled to room temperature and filtered.

  Sulfur in the obtained filtrate is analyzed by high performance liquid chromatography, and the amount of sulfur in the dihalogenobenzobisthiadiazole compound is measured using a calibration curve prepared from the peak area value of sulfur of the standard product.

  The subject of the present invention is also a general formula (2) in the presence of a base.

  Is reacted with a halogenating agent in a halogenated hydrocarbon solvent to obtain a crude dihalogenobenzobisthiadiazole compound, and then the resulting crude dihalogeno compound is obtained. This can also be solved by a method for producing a high-purity dihalogenobenzobisthiadiazole compound in which a benzobisthiadiazole compound and a halogenated hydrocarbon are contact-treated.

  According to the present invention, a high-purity dihalogenobenzobisthiadiazole compound having a reduced sulfur content can be provided. In addition, according to the present invention, this dihalogenobenzobisthiadiazole compound having a sufficiently high purity that can be used as a synthetic intermediate for organic semiconductor materials can be provided.

It is the schematic of a Soxhlet extractor.

(High purity dihalogenobenzobisthiadiazole compound)
The high-purity dihalogenobenzobisthiadiazole compound of the present invention is a compound represented by the general formula (1), and the sulfur content measured by the following measurement method is 1% by weight or less. Indicates. When used as a synthetic intermediate for organic semiconductor materials, the sulfur content is preferably 0.5% by weight or less, and more preferably 0.3% by weight or less. However, the case where the sulfur content is 0% by weight is excluded.

  By setting the sulfur content of the dihalogenobenzobisthiadiazole compound to 1% by weight or less, the catalytic reaction proceeds in a good yield and can be used as a synthetic intermediate for organic semiconductor materials.

(Method for measuring sulfur content of high-purity dihalogenobenzobisthiadiazole compounds)
The sulfur content of the high purity dihalogenobenzobisthiadiazole compound is measured by the following procedure.
(1) A dihalogenobenzobisthiadiazole compound and 1,2-dichlorobenzene are mixed and dissolved by heating (140 ° C. to 160 ° C.), then cooled to room temperature (20 ° C. to 30 ° C.) and filtered.
(2) The sulfur in the obtained filtrate is analyzed by high performance liquid chromatography.
(3) The amount of sulfur in the dihalogenobenzobisthiadiazole compound is measured using a calibration curve created from the standard sulfur peak area value.

  In this measurement method, the amount of 1,2-dichlorobenzene used is adjusted as appropriate, but it is preferably used in an amount of 100 mL to 1 L with respect to 1 g of the dihalogenobenzobisthiadiazole compound. By setting it as the said range, sulfur in a dihalogeno benzobis thiadiazole compound melt | dissolves completely, and it can measure sulfur content efficiently by one measurement.

  In this measurement method, the sulfur content at any concentration except 0% by weight can be changed by appropriately changing the amount and concentration of 1,2-dichlorobenzene, the amount of dihalogenobenzobisthiadiazole compound used, and the measuring equipment. However, the measurable sulfur content is 10 ppm or more, preferably 30 ppm or more, based on the dihalogenobenzobisthiadiazole compound in the industrially preferred range of use and concentration.

  Here, the calibration curve created from the peak value of sulfur of the standard product is obtained by analyzing a sample of a standard solution (commercial product) obtained by dissolving sulfur in 1,2-dichlorobenzene and analyzing it. Represents the correlation between the peak area of sulfur and the amount of sulfur.

(Synthesis of high-purity dihalogenobenzobisthiadiazole compounds)
The high-purity dihalogenobenzobisthiadiazole compound of the present invention is represented by the general formula (2) in the presence of a base.

Is reacted with a halogenating agent in a halogenated hydrocarbon solvent to obtain a crude dihalogenobenzobisthiadiazole compound, and then the resulting crude dihalogeno compound is obtained. It is produced by contacting a benzobisthiadiazole compound with a halogenated hydrocarbon.

  Hereinafter, a process of obtaining a crude dihalogenobenzobisthiadiazole compound by reacting a tetraaminobenzene compound (including its acid salt) with a halogenating agent in a halogenated hydrocarbon solvent in the presence of a base is described as “the present invention”. And the step of contacting the resulting crude dihalogenobenzobisthiadiazole compound with the halogenated hydrocarbon is referred to as “treatment of the present invention”.

(About “the reaction of the present invention”)
The tetraaminobenzene compound used in the reaction of the present invention may be used as it is or as an acid salt thereof. Examples of the acid for forming the acid salt include hydrogen fluoride, hydrogen chloride, hydrobromic acid, A hydrohalic acid such as hydroiodic acid can be used, and a hydrohalic acid having the same halogen atom as that of the halogenating agent is preferably used. Examples of the tetraaminobenzene compound that is a hydrogen halide salt include 1,2,4,5-tetraaminobenzene hydrochloride, 1,2,4,5-tetraaminobenzene hydrobromide, and the like. It is done.

  Examples of the halogenating agent used in the reaction of the present invention include thionyl chloride and thionyl bromide, and preferably thionyl bromide is used. These halogenating agents may be used in combination of two or more as long as the halogen atoms are the same.

  The amount of the halogenating agent to be used is preferably 2 to 100 mol, more preferably 3 to 50 mol, more preferably 4 to 20 mol, per 1 mol of the tetraaminobenzene compound. By setting it as the said range, reaction can be implemented with a yield, operativity, and economical efficiency.

  Examples of the base used in the reaction of the present invention include fragrances such as pyridine, N-methylpyridine, 2-chloropyridine, 2-bromopyridine, piperidine, pyrimidine, quinoline, acridine, picoline, bipyridine, and 2,6-lutidine. Group amines, trimethylamine, N, N-dimethylethylamine, N, N-diethylmethylamine, triethylamine, N, N-dimethylpropylamine, N, N-dimethylbutylamine, N, N-dimethylpentylamine, N, N- Diethylpropylamine, N, N-dipropylethylamine, N, N-dipropylmethylamine, N, N-diethylpentylamine, N-ethyl-N-methylpentylamine, tributylamine, tripropylamine, triisopropylamine, Aliphatic tertiary amines such as It is, but preferably, aromatic amines, more preferably, pyridine is used. In addition, you may use these bases individually or in mixture of 2 or more types.

  The amount of the base used is preferably 2 mol to 100 mol, more preferably 3 mol to 50 mol, and more preferably 4 mol to 20 mol with respect to 1 mol of the tetraaminobenzene compound. By setting it as the said range, reaction can be implemented with a sufficient yield, operativity, and economical efficiency.

  Examples of the halogenated hydrocarbon used in the reaction of the present invention include aliphatic halogenated hydrocarbons such as methylene chloride, chloroform and 1,2-dichloroethylene, and aromatic halogenated hydrocarbons such as chlorobenzene and dichlorobenzene. However, preferably methylene chloride, chloroform, 1,2-dichloroethylene is used. In addition, you may use these halogenated hydrocarbons individually or in mixture of 2 or more types.

The halogenated hydrocarbon is preferably 1 L to 100 L, more preferably 4 L to 10 L with respect to 1 mol of the tetraaminobenzene compound. By setting it as the said range, reaction can be implemented with a sufficient yield, operativity, and economical efficiency.

  The reaction of the present invention is carried out, for example, by a method of mixing tetraaminobenzene, a halogenating agent, a base and a halogenated hydrocarbon solvent and reacting them with stirring. The reaction temperature at that time is preferably −30 ° C. to 200 ° C., more preferably 0 ° C. to 100 ° C., and the reaction pressure is not particularly limited. By making reaction temperature into the said range, reaction can be advanced smoothly, suppressing a side reaction, and the target object can be acquired efficiently.

  After completion of the reaction of the present invention, the reaction product is filtered and a crude dihalogenobenzobisthiadiazole compound is obtained by filtration, but is used in the next treatment after drying if necessary.

(About “Processing of the Present Invention”)
Examples of the halogenated hydrocarbon used in the treatment of the present invention (contact treatment with the crude dihalogenobenzobisthiadiazole compound obtained by the reaction of the present invention) include fatty acids such as methylene chloride, chloroform, 1,2-dichloroethylene, etc. Aromatic halogenated hydrocarbons such as aromatic halogenated hydrocarbons, chlorobenzene, dichlorobenzene and the like, preferably chloroform, 1,2-dichloroethylene, chlorobenzene, 1,2-dichlorobenzene, more preferably chloroform, 1 , 2-dichloroethylene and chlorobenzene are used. In addition, you may use these halogenated hydrocarbons individually or in mixture of 2 or more types.

  The amount of the halogenated hydrocarbon to be used is preferably 1 mL to 10 L, more preferably 10 mL to 500 mL, per 1 g of the crude dihalogenobenzobisthiadiazole compound. By setting it as the said range, a process can be implemented with sufficient yield, operativity, and economical efficiency.

The contact treatment in the treatment of the present invention refers to a treatment in which a crude dihalogenobenzobisthiadiazole compound and a halogenated hydrocarbon are sufficiently brought into contact by stirring or extraction. This contact treatment is not particularly limited as long as impurities are sufficiently removed and a high purity dihalogenobenzobisthiadiazole compound is used, but it is selected from the group consisting of the following (1), (2), and (3). A method comprising at least one is a preferred embodiment.
(1) A method in which a contact treatment of a crude dihalogenobenzobisthiadiazole compound and a halogenated hydrocarbon is carried out by mixing and stirring,
(2) A method in which a contact treatment of a crude dihalogenobenzobisthiadiazole compound and a halogenated hydrocarbon is performed by Soxhlet extraction,
(3) Method of performing contact treatment of crude dihalogenobenzobisthiadiazole compound and halogenated hydrocarbon by recrystallization Note that these reaction treatments may be carried out alone or in combination of a plurality of treatments, A method in which Soxhlet extraction or recrystallization is performed after first performing a process by mixing and stirring is more preferable.

(1) Method by mixing and stirring The crude dihalogenobenzobisthiadiazole compound is added to a halogenated hydrocarbon solvent, mixed, heated and stirred, and then the resulting solution is cooled to room temperature (20 ° C to 30 ° C). And filter. At this time, since sulfur dissolves in the halogenated hydrocarbon solvent, it is separated to the filtrate side. The obtained filtrate can be dried to obtain a high-purity dihalogenobenzobisthiadiazole compound. In this method, the heating temperature is appropriately changed according to the solvent and pressure to be used, but it is preferably 40 ° C. or higher, more preferably 50 ° C. or higher, and further preferably 60 ° C. or higher.

(2) Method Performed by Soxhlet Extraction An example of obtaining the high purity dihalogenobenzobisthiadiazole compound of the present invention will be described with reference to FIG. The crude dihalogenobenzobisthiadiazole compound (solid) is placed in a cylindrical filter paper, placed in a Soxhlet extraction apparatus, a halogenated hydrocarbon solvent is placed in the flask, and heated to reflux. This heating temperature can be appropriately changed according to the solvent and pressure used. The halogenated hydrocarbon solvent vapor generated in the flask reaches the cooler (4) through the side pipe (3) and condenses. The condensed halogenated hydrocarbon solvent is dropped into the cylindrical filter paper (5), and the dihalogenobenzobisthiadiazole compound is extracted from the solid in the cylindrical filter paper by the dropped solvent and stored as a solution. When a certain amount of solution is accumulated, the accumulated solution flows down into the flask (1) by the siphon (6). By this repetition, the extracted dihalogenobenzobisthiadiazole compound is concentrated in the flask (1) and precipitated as a solid in the flask. After completion of Soxhlet extraction, the mixture is cooled to room temperature, and the precipitate in the extract is collected by filtration. At this time, since sulfur dissolves in the halogenated hydrocarbon solvent, it is separated to the filtrate side. The obtained precipitate can be dried to obtain a highly pure dihalogenobenzobisthiadiazole compound.

(3) Method performed by recrystallization A crude dihalogenobenzobisthiadiazole compound is added to a halogenated hydrocarbon solvent and heated to reflux to be completely dissolved. This heating temperature can be appropriately changed according to the solvent and pressure used. The solution is cooled to room temperature (20 ° C. to 30 ° C.), and the precipitate is collected by filtration. At this time, since sulfur dissolves in the halogenated hydrocarbon solvent, it is separated to the filtrate side. The obtained filtrate can be dried to obtain a high-purity dihalogenobenzobisthiadiazole compound.

  By the treatment of the present invention, a high-purity dihalogenobenzobisthiadiazole compound is obtained. This is because the sulfur content measured by the above-described sulfur measurement method is specified to be 1% by weight or less. It is a benzobisthiadiazole compound. However, the case where the sulfur content is 0% by weight is excluded.

  The high-purity dihalogenobenzobisthiadiazole compound can be used in the production of an organic semiconductor material having benzobisthiadiazole as the main skeleton (for example, see Examples 5, 6, 7 and 8 described later).

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated concretely, this invention is not limited to a following example. Abbreviations are as follows.

DBBBT; 4,8-dibromobenzobisthiadiazole crude, crude DBBBT; 4,8-dibromobenzobisthiadiazole C8TBBT not subjected to any of the above-mentioned three types of contact treatment (mixing heating stirring, Soxhlet extraction, recrystallization); 4,8-bis (5-octyl-2-thienyl) benzobisthiadiazole

Analytical conditions for high performance liquid column chromatography are as follows.
(Sulfur analysis)
Column: CHIRALPAK IA (manufactured by Daicel Chemical Industries) 4.6 × 250 mm ID
Mobile phase: n-hexane Measurement wavelength: 300 nm
Column temperature: 30 ° C
Flow rate: 1.0 mL / min
(Analysis of DBBBT and C8TBBT)
Column: CHIRALPAK IA (manufactured by Daicel Chemical Industries) 4.6 × 250 mm ID
Mobile phase: (A) n-hexane: (B) Concentration of chloroform B: 20% (0 min) → 90% (10 min) → 90% (24 min) → 20% (25 min) → 20% (40 min)
Measurement wavelength: 345 nm
Column temperature: 40 ° C
Flow rate: 1.0 mL / min

Example 1 (Synthesis of high purity 4,8-dibromobenzobisthiadiazole (DBBBT))
Into a four-necked flask having an internal volume of 1000 mL equipped with a stirrer, a dropping funnel and a reflux condenser, 19.9 g (0.0431 mol) of 1,2,4,5-tetraaminobenzenetetrahydrobromide and 300 mL of chloroform were added. After mixing, 33.4 mL (0.431 mol) of thionyl bromide and 48 mL (0.60 mol) of pyridine were added in this order, and the mixture was refluxed (55 ° C. to 65 ° C.) at room temperature (20 ° C. to 30 ° C.) for 3 hours with stirring. (C) for 12 hours.

  After completion of the reaction, the reaction solution was cooled to room temperature, 300 mL of methanol was added, and the reaction solution was filtered. The residue was washed with hydrochloric acid, water and methanol in this order, and then dried at 70 ° C. under reduced pressure to obtain 11.3 g of crude DBBBT.

  11.3 g of the obtained crude DBBBT and 300 mL of chloroform were added to a 500 mL four-necked flask equipped with a stirrer and a reflux condenser, and reacted under reflux (55 ° C. to 65 ° C.) for 3 hours while stirring. . The obtained solution was cooled to room temperature (20 ° C. to 30 ° C.) and filtered, and the residue was washed with chloroform. The obtained solid was dried at 60 ° C. under reduced pressure to obtain 9.9 g of DBBBT (crude acquisition yield; 65%).

  3 g of the DBBBT (solid) was placed in a cylindrical filter paper, placed in a Soxhlet extraction apparatus shown in FIG. 1, 250 mL of chlorobenzene was placed in the flask, and the mixture was stirred under reflux (130 ° C. to 140 ° C.) for 14 hours. The obtained filtrate was cooled to room temperature (20 ° C. to 30 ° C.), and then the precipitated solid was filtered. After filtration, the residue was dried at 70 ° C. under reduced pressure to obtain 2.23 g of DBBBT as a dark reddish brown solid (purification recovery rate: 74%).

  0.05 g of the obtained DBBBT and 30 mL of 1,2-dichlorobenzene were mixed, heated at 150 ° C. to elute sulfur, cooled to room temperature (20 ° C. to 30 ° C.), and filtered. Next, sulfur in the filtrate was analyzed by high performance liquid chromatography, and the amount of sulfur in the dihalogenobenzobisthiadiazole compound was measured using a calibration curve created from the standard sulfur peak area value. The content was below the detection limit, and the obtained DBBBT was found to be a high purity product.

Example 2 (Synthesis of high purity 4,8-dibromobenzobisthiadiazole (DBBBT))
To a 500 mL four-necked flask equipped with a stirrer, a dropping funnel and a reflux condenser, 20.0 g (0.0431 mol) of 1,2,4,5-tetraaminobenzenetetrahydrobromide and 300 mL of chloroform were added. After mixing, 34.0 mL (0.431 mol) of thionyl bromide and 49 mL (0.60 mol) of pyridine were added in this order, and the mixture was refluxed (55 ° C. to 65 ° C.) for 1 hour at room temperature (20 ° C. to 30 ° C.) with stirring. (C) for 12 hours.

  After completion of the reaction, the reaction solution was cooled to room temperature, 300 mL of methanol was added, and the reaction solution was filtered. The residue was washed with hydrochloric acid, water and methanol in this order, and then dried at 70 ° C. under reduced pressure to obtain 11.3 g of crude DBBBT.

  11.3 g of the obtained crude DBBBT and 300 mL of chloroform were added to a 500 mL four-necked flask equipped with a stirrer and a reflux condenser, and reacted under reflux (55 ° C. to 65 ° C.) for 1 hour while stirring. . The obtained solution was cooled to room temperature (20 ° C. to 30 ° C.) and filtered, and the residue was washed with chloroform. The resulting solid was dried at 60 ° C. under reduced pressure.

  The obtained DBBBT (solid) was divided into two parts, one was placed in a cylindrical filter paper, placed in the Soxhlet extraction apparatus shown in FIG. 1, 250 mL of chlorobenzene was placed in the flask, and the mixture was refluxed (130 ° C. to 140 ° C.) at 14 Stir for hours. The obtained filtrate was cooled to room temperature (20 ° C. to 30 ° C.), and then the precipitated solid was filtered. After filtration, the residue was dried at 60 ° C. under reduced pressure to obtain DBBBT as a dark reddish brown solid. Soxhlet extraction was performed in the same manner on the other divided DBBBT. Together, 8.2 g of DBBBT was obtained (acquired yield of purified product; 55%).

  The same experiment was further performed three times, and 28.1 g of purified DBBBT was obtained in a total of four experiments.

  The obtained DBBBT (50 mg) and 1,2-dichlorobenzene (about 5 g) were precisely weighed and mixed, heated at 150 ° C. for 15 minutes to elute sulfur, cooled to room temperature (20 ° C. to 30 ° C.) and filtered. did. Next, sulfur in the filtrate was analyzed by high performance liquid chromatography, and the amount of sulfur in the dihalogenobenzobisthiadiazole compound was measured using a calibration curve created from the standard sulfur peak area value. The content was 32 ppm. In this way, the sulfur content could be measured using the DBBBT solution having a high concentration.

Example 3 (Synthesis of high purity 4,8-dibromobenzobisthiadiazole (DBBBT))
Into a four-necked flask having an internal volume of 1000 mL equipped with a stirrer, a dropping funnel and a reflux condenser, 19.9 g (0.0431 mol) of 1,2,4,5-tetraaminobenzenetetrahydrobromide and 300 mL of chloroform were added. After mixing, 33.4 mL (0.431 mol) of thionyl bromide and 48 mL (0.60 mol) of pyridine were added in this order, and the mixture was refluxed (55 ° C. to 65 ° C.) at room temperature (20 ° C. to 30 ° C.) for 3 hours with stirring. (C) for 12 hours.

  After completion of the reaction, the reaction solution was cooled to room temperature (20 ° C. to 30 ° C.), 300 mL of methanol was added, and the reaction solution was filtered. The residue was washed with hydrochloric acid, water and methanol in this order, and then dried at 70 ° C. under reduced pressure to obtain 11.3 g of crude DBBBT.

  11.3 g of the obtained crude DBBBT and 300 mL of chloroform were added to a 500 mL four-necked flask equipped with a stirrer and a reflux condenser, and reacted under reflux (55 ° C. to 65 ° C.) for 3 hours while stirring. . The obtained solution was cooled to room temperature (20 ° C. to 30 ° C.) and filtered, and the residue was washed with chloroform. The obtained solid was dried at 60 ° C. under reduced pressure to obtain 9.9 g of DBBBT (crude acquisition yield: 65%).

  1 g of DBBBT and 100 mL of chlorobenzene were added to an eggplant flask having an internal volume of 300 mL equipped with a stirrer and a reflux condenser, and reacted for 6 hours under reflux (130 ° C. to 140 ° C.) while stirring. The resulting solution was cooled to room temperature (20 ° C. to 30 ° C.) and filtered, and the residue was dried under reduced pressure at 70 ° C. to give DBBBT 0.86 g (purification recovery rate: 86%) as a dark reddish brown solid. Got.

  0.05 g of the obtained DBBBT and 30 mL of 1,2-dichlorobenzene were mixed and dissolved by heating at 150 ° C., and then cooled to room temperature (20 ° C. to 30 ° C.) and filtered. Next, sulfur in the filtrate was analyzed by high performance liquid chromatography, and the amount of sulfur in the dihalogenobenzobisthiadiazole compound was measured using a calibration curve created from the standard sulfur peak area value. The content was below the detection limit, and the obtained DBBBT was found to be a high purity product.

Example 4 (Synthesis of high purity 4,8-dibromobenzobisthiadiazole (DBBBT))
Into a four-necked flask having an internal volume of 1000 mL equipped with a stirrer, a dropping funnel and a reflux condenser, 20 g (0.0433 mol) of 1,2,4,5-tetraaminobenzenetetrahydrobromide and 300 mL of chloroform were mixed. Thereafter, 33.6 mL (0.433 mol) of thionyl bromide and 49 mL (0.61 mol) of pyridine were added in this order, and the mixture was stirred at room temperature (20 ° C. to 30 ° C.) for 3 hours under reflux (55 ° C. to 65 ° C.). For 12 hours.

  After completion of the reaction, the reaction solution was cooled to room temperature, and after adding 400 mL of methanol, the reaction solution was filtered. The residue was washed with hydrochloric acid, water, and methanol in that order, and then dried at 70 ° C. under reduced pressure to obtain 14.8 g of crude DBBBT (crude product yield: 97%).

  14.5 g of the synthesized crude DBBBT was placed in an eggplant flask having an internal volume of 500 mL equipped with a stirrer and a reflux condenser, added to 300 mL of chloroform, and reacted under reflux (55 ° C. to 65 ° C.) for 5 hours while stirring. After cooling to room temperature (20 ° C. to 30 ° C.), the precipitate was collected by filtration and washed with chloroform. The obtained solid was dried under reduced pressure at 70 ° C. to obtain 12.7 g of DBBBT as a dark reddish brown solid (purification recovery rate: 88%).

  0.05 g of the obtained DBBBT and 30 mL of 1,2-dichlorobenzene were mixed and dissolved by heating at 150 ° C., and then cooled to room temperature (20 ° C. to 30 ° C.) and filtered. Next, sulfur in the filtrate was analyzed by high performance liquid chromatography, and the amount of sulfur in the dihalogenobenzobisthiadiazole compound was measured using a calibration curve created from the standard sulfur peak area value. The content was 0.3% by weight, and the obtained DBBBT was found to be a high-purity product.

Comparative Example 1 (Synthesis of 4,8-dibromobenzobisthiadiazole (DBBBT))
To a four-necked flask with an internal volume of 1000 mL equipped with a stirrer, a dropping funnel and a reflux condenser, 20.0 g (0.0433 mol) of 1,2,4,5-tetraaminobenzenetetrahydrobromide and 300 mL of chloroform were added. After mixing, 33.6 mL (0.433 mol) of thionyl bromide and 48 mL (0.60 mol) of pyridine were added in this order, and the reaction was carried out with stirring at room temperature for 3 hours and with heating under reflux for 12 hours.

  After completion of the reaction, the reaction solution was cooled to room temperature, 300 mL of methanol was added, and the reaction solution was filtered. The residue was washed with hydrochloric acid, water, and methanol in that order and then dried at 70 ° C. under reduced pressure to obtain 14.8 g of DBBBT (acquisition yield: 97%).

  0.05 g of the obtained DBBBT and 30 mL of 1,2-dichlorobenzene were mixed and dissolved by heating at 150 ° C., and then cooled to room temperature (20 ° C. to 30 ° C.) and filtered. Next, sulfur in the filtrate was analyzed by high performance liquid chromatography, and the amount of sulfur in the dihalogenobenzobisthiadiazole compound was measured using a calibration curve created from the standard sulfur peak area value. The content was 23% by weight.

Example 5 (Synthesis of 4,8-bis (5-octyl-2-thienyl) benzobisthiadiazole (C8TBBT))
In a glass reaction vessel having an internal volume of 10 mL equipped with a stirrer, DBBBT synthesized in Example 1 100 mg (0.284 mmol), tri (n-butyl) (5-octyl-2-thienyl) tin) 551 mg (1.14 mmol) ), 60 mg (0.085 mmol) of dichlorobis (triphenylphosphine) palladium and 3 mL of toluene were added and reacted at 100 ° C. for 1 hour with stirring.

  When the reaction solution was analyzed after completion of the reaction, 156 mg of C8TBBT was produced (reaction yield; 94%).

Example 6 (Synthesis of 4,8-bis (5-octyl-2-thienyl) benzobisthiadiazole (C8TBBT))
In a glass reaction vessel having an internal volume of 10 mL equipped with a stirrer, DBBBT synthesized in Example 3 100 mg (0.284 mmol), tri (n-butyl) (5-octyl-2-thienyl) tin) 551 mg (1.14 mmol) ), 60 mg (0.085 mmol) of dichlorobis (triphenylphosphine) palladium and 3 mL of toluene were added and reacted at 100 ° C. for 1 hour with stirring.

  When the reaction solution was analyzed after completion of the reaction, 144 mg of C8TBBT was produced (reaction yield; 87%).

Example 7 (Synthesis of 4,8-bis (5-octyl-2-thienyl) benzobisthiadiazole (C8TBBT))
In a glass reaction vessel having an internal volume of 10 mL equipped with a stirrer, DBBBT synthesized in Example 4 100 mg (0.284 mmol), tri (n-butyl) (5-octyl-2-thienyl) tin) 551 mg (1.14 mmol) ), 60 mg (0.085 mmol) of dichlorobis (triphenylphosphine) palladium and 3 mL of toluene were added and reacted at 100 ° C. for 1 hour with stirring.

  When the reaction solution was analyzed after completion of the reaction, 132 mg of C8TBBT was produced (reaction yield; 80%).

Example 8 (Synthesis of 4,8-bis (5-octyl-2-thienyl) benzobisthiadiazole (C8TBBT))
1 mg of standard sulfur is added to 100 mg (0.284 mmol) of DBBBT synthesized in Example 1 in a glass reaction vessel having an internal volume of 10 mL equipped with a stirrer so that the sulfur content in DBBBT is 1 wt%. It was adjusted. Further, 551 mg (1.14 mmol) of tri (n-butyl) (5-octyl-2-thienyl) tin, 60 mg (0.085 mmol) of dichlorobis (triphenylphosphine) palladium and 3 mL of toluene were added to the reaction vessel, and the mixture was stirred. The reaction was carried out at 100 ° C. for 1 hour.

  When the reaction solution was analyzed after completion of the reaction, 137 mg of C8TBBT was produced (reaction yield; 83%).

Comparative Example 2 (Synthesis of 4,8-bis (5-octyl-2-thienyl) benzobisthiadiazole (C8TBBT))
In a glass reaction vessel having an internal volume of 10 mL equipped with a stirrer, 100 mg of crude DBBBT synthesized in Comparative Example 1, 551 mg (1.14 mmol) of tri (n-butyl) (5-octyl-2-thienyl) tin, dichlorobis ( Triphenylphosphine) palladium (60 mg, 0.085 mmol) and toluene (3 mL) were added, and the mixture was reacted at 100 ° C. for 1 hour with stirring.

  When the reaction solution was analyzed after completion of the reaction, C8TBBT was not produced.

  As described above, a high-purity dihalogenobenzobisthiadiazole compound having a sulfur content reduced to 1 wt% or less could be provided by contact treatment with a halogenated hydrocarbon. It was also found that this dihalogenobenzobisthiadiazole compound is sufficiently high in purity so that it can be used as a synthetic intermediate for organic semiconductor materials.

  The present invention relates to a highly pure dihalogenobenzobisthiadiazole compound having a reduced sulfur content. A dihalogenobenzobisthiadiazole compound is a useful compound as a raw material for producing various organic semiconductor materials, for example.

Claims (7)

In the presence of a base, general formula (2)

A tetraaminobenzene compound (including an acid salt thereof) represented by the above and a halogenating agent were reacted in a halogenated hydrocarbon solvent to obtain a crude dihalogenobenzobisthiadiazole compound, and then obtained. General formula (1) in which the sulfur content measured by the following measurement method is 1% by weight or less by contacting a crude dihalogenobenzobisthiadiazole compound with a halogenated hydrocarbon.

(In the formula, X represents a halogen atom.)
A method for producing a high-purity dihalogenobenzobisthiadiazole compound represented by the formula:
However, the case where the sulfur content is 0% by weight is excluded.
Sulfur measurement method;
A dihalogenobenzobisthiadiazole compound and 1,2-dichlorobenzene are mixed and dissolved by heating, and then cooled to room temperature and filtered.
Sulfur in the obtained filtrate is analyzed by high performance liquid chromatography, and the amount of sulfur in the dihalogenobenzobisthiadiazole compound is measured using a calibration curve prepared from the peak area value of sulfur of the standard product.   At least one selected from the group consisting of a method in which the contact treatment between the crude dihalogenobenzobisthiadiazole compound and the halogenated hydrocarbon is performed by mixing and heating, a method in which soxhlet extraction is performed, and a method in which recrystallization is performed. The method for producing a high-purity dihalogenobenzobisthiadiazole compound according to claim 1, wherein the method comprises:   The method for producing a high-purity dihalogenobenzobisthiadiazole compound according to claim 2, wherein the contact treatment between the crude dihalogenobenzobisthiadiazole compound and the halogenated hydrocarbon is carried out by mixing and stirring.   The method for producing a high-purity dihalogenobenzobisthiadiazole compound according to claim 2, wherein the contact treatment between the crude dihalogenobenzobisthiadiazole compound and the halogenated hydrocarbon is performed by Soxhlet extraction.   The method for producing a high-purity dihalogenobenzobisthiadiazole compound according to claim 2, wherein the contact treatment between the crude dihalogenobenzobisthiadiazole compound and the halogenated hydrocarbon is performed by recrystallization. General formula (1) whose sulfur content measured with the following measuring method is 1 weight% or less

(In the formula, X represents a halogen atom.)
A high-purity dihalogenobenzobisthiadiazole compound represented by the formula:
However, the case where the sulfur content is 0% by weight is excluded.
Sulfur measurement method;
A dihalogenobenzobisthiadiazole compound and 1,2-dichlorobenzene are mixed and dissolved by heating, and then cooled to room temperature and filtered.
Sulfur in the obtained filtrate is analyzed by high performance liquid chromatography, and the amount of sulfur in the dihalogenobenzobisthiadiazole compound is measured using a calibration curve prepared from the peak area value of sulfur of the standard product.   Use of the high-purity dihalogenobenzobisthiadiazole compound according to claim 6 in the production of an organic semiconductor material having benzobisthiadiazole as a main skeleton.

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