CN114213389B

CN114213389B - Synthesis method of benzo [ b ] naphtho [2,3-d ] thiophene

Info

Publication number: CN114213389B
Application number: CN202111644822.XA
Authority: CN
Inventors: 吴清来; 宋文志; 李显跃; 杨雪
Original assignee: Bangnuo Suzhou New Materials Co ltd
Current assignee: Bangnuo Suzhou New Materials Co ltd
Priority date: 2021-12-30
Filing date: 2021-12-30
Publication date: 2024-01-09
Anticipated expiration: 2041-12-30
Also published as: CN114213389A

Abstract

The invention discloses a synthesis method of benzo [ b ] naphtho [2,3-d ] thiophene, which comprises the following steps: 2- (methylthio) aniline is prepared by taking 2-aminobenzo [ d ] thiazole as a raw material under the action of alkali and haloalkane; preparing (2-iodophenyl) (methyl) sulfane from 2- (methylthio) aniline; preparing 1-iodo-2- (methylsulfinyl) benzene from (2-iodophenyl) (methyl) sulfane; 1- (2- (methylsulfonylphenyl)) naphthalene is prepared from 1-iodo-2- (methylsulfinyl) benzene and compound S5; benzo [ b ] naphtho [2,3-d ] thiophene is prepared from 1- (2- (methylsulfonylphenyl)) naphthalene. The invention adopts a green environment-friendly route to obtain the benzo [ b ] naphtho [2,3-d ] thiophene with high yield and high quality.

Description

Synthesis method of benzo [ b ] naphtho [2,3-d ] thiophene

Technical Field

The invention belongs to the field of organic photoelectricity, and particularly relates to a preparation method of a benzo-thiophene compound, namely benzo [ b ] naphtho [2,3-d ] thiophene.

Background

Benzothiophenes and derivatives thereof are an important class of heterocyclic compounds and have wide application in industry, agriculture, pharmaceutical industry and the like. For example: benzothiazoles are a constituent of a variety of optical brighteners and fuels; poly (p-phenylene benzobisthiazole) has excellent heat resistance, oxidation resistance, hydrolysis resistance and chemical corrosion resistance; other derivatives can be used as chemiluminescent and capillary electrophoresis; in recent years, the compounds are paid attention to the fields of organic light-emitting diode display, chemical sensors, organic solar cells, field effect transistors and the like due to the characteristic of easy modification and processing.

The benzothiazole and the derivative molecular main body thereof are easy to construct D-A class small molecules and polymers of electron donors (Donor) and electron acceptors (acceptors), and the class of compounds show unique advantages in the field of organic photoelectric materials due to higher carrier mobility and narrower energy systems. In the heterojunction solar cell device, the open-circuit voltage of the cell is in a linear relation with the LOMO energy level of an electron donor material and the LUMO energy level of an electron acceptor material (PCBM) which form a photosensitive layer, and on the premise of ensuring that the donor and the acceptor have enough LUMO energy level difference, the deeper the HOMO of the donor material is beneficial to improving the open-circuit voltage of the cell, so that higher photoelectric conversion efficiency is obtained.

Benzo [ b ]]Naphtho [2,3-d]Thiophene of the formula C ₁₆ H ₁₀ S, foreign language names: benzo [ b ]]naphtho[2,3-d]thiophene, which is the most widely used donor unit in organic photoelectric materials, shows higher potential before application in the construction of D-A molecules.

Benzo [ b ] naphtho [2,3-d ] thiophenes, the preparation methods known at present are:

1. phenyl-naphthalene-sulfane (phenyl-2-yl) sulfane as starting material in Pd (tfa) ₂ In a system in which silver acetate, potassium carbonate and trimethylacetic acid exist, benzo [ b ] is generated]Naphtho [2,3-d]Thiophene, 56% yield. The raw material (nano-2-yl) sulfate) used in the method is expensive, the catalyst dosage is large (10% of the raw material molar amount), the product yield is low, and the method is unfavorable for industrial production.

2. The benzo [ b ] naphtho [2,3-d ] thiophene is generated by using naphthalene-2-thio compound and o-halogenated benzene under the action of light and ammonia gas, and the yield is 46%. (J.Org.chem., vol.58, no.9,1993) the product obtained by this method is a mixture, difficult to separate, and unfavorable for realizing industrial production.

Disclosure of Invention

The invention aims to provide a synthesis method of benzo [ b ] naphtho [2,3-d ] thiophene, which adopts a green environment-friendly route to obtain the benzo [ b ] naphtho [2,3-d ] thiophene with high yield and high quality.

In order to solve the technical problems, the invention provides a synthesis method of benzo [ b ] naphtho [2,3-d ] thiophene, which comprises the following steps:

1) Adding 2-aminobenzo [ d ] thiazole (S1) into alkali liquor, heating and refluxing for 12-20 h, cooling to room temperature, then dropwise adding haloalkane, and continuously stirring for 2-4 h; the obtained reaction liquid is subjected to post-treatment to obtain 2- (methylthio) aniline (S2);

2-aminobenzo [ d ] thiazole: alkali: haloalkane = 1:10 to 40:1 to 2 molar ratio (preferably 1:15 to 25:1 to 1.5, more preferably 1:18 to 20:1 to 1.2);

description: dissolving alkali in water to obtain alkali liquor;

2) Dripping an acetone solution of 2- (methylthio) aniline into a hydrochloric acid solution at 0-5 ℃, then cooling to-50 to-40 ℃, dripping a nitrite aqueous solution, and reacting for 0.5-3 h at the temperature of (-50 to-40 ℃); then adding aqueous solution of iodized inorganic salt dropwise, then reacting for 1-1.5 hours at room temperature, and carrying out post-treatment on the obtained reaction liquid to obtain (2-iodophenyl) (methyl) sulfane (S3);

2- (methylthio) aniline: nitrite: iodinated inorganic salts: hydrochloric acid=1:1 to 4:1 to 5 molar ratio (preferably 1:1 to 1.5:2 to 2.5:2.5 to 3);

description: mixing concentrated hydrochloric acid with water according to the volume ratio of 1:1-1:1.1 to obtain hydrochloric acid solution;

3) Adding acetic acid into (2-iodophenyl) (methyl) sulfane at 0-5 ℃, dropwise adding an oxidant, stirring at room temperature for 12-20 h, and performing aftertreatment on the obtained reaction solution to obtain 1-iodo-2- (methylsulfinyl) benzene (S4);

(2-iodophenyl) (methyl) sulfane: oxidant = 1:1 to 5 molar ratio (preferably 1:1 to 2, more preferably 1:1 to 1.5);

0.05mol S3 is matched with 150-250 mL of acetic acid;

4) Dissolving 1-iodo-2- (methylsulfinyl) benzene (S4) and a compound S5 in an organic solvent, adding a weak base aqueous solution, adding a catalyst under the protection of inert gas (such as nitrogen) to react for 12-20 hours at 70+/-10 ℃, and performing post-treatment on the obtained reaction solution to obtain 1- (2- (methylsulfonyl) naphthalene (S6);

the compound S5 is a boric acid coupling reagent; the catalyst is tetra (triphenylphosphine) palladium;

1-iodo-2- (methylsulfinyl) benzene: compound S5: weak base = 1:1 to 1.5:1 to 8 molar ratio (preferably 1:1 to 1.2:6 to 7);

1-iodo-2- (methylsulfinyl) benzene (S4): catalyst=100:0.8-1.2 mass ratio;

5) Adding 1- (2- (methyl sulfoxide phenyl)) naphthalene into sulfuric acid at a low temperature of 0-5 ℃, stirring for 2+/-0.5 h at room temperature, pouring into ice water, regulating the pH value to 8-8.5, heating and refluxing for 1-6 h, adding an alcohol solution and refluxing for 0.5-2 h, and performing post-treatment on the obtained reaction solution to obtain benzo [ b ] naphtho [2,3-d ] thiophene (T1) serving as a target product;

1- (2- (methylsulfonylphenyl)) naphthalene: sulfuric acid=1:5 to 20 molar ratio (preferably 1:15 to 18).

Description: 1- (2- (methylsulfonylphenyl)) naphthalene was added to sulfuric acid in portions, typically in two portions, at 30 minutes intervals.

As an improvement of the synthesis method of benzo [ b ] naphtho [2,3-d ] thiophene of the present invention, in step 1):

the alkali is inorganic alkali or organic alkali; the haloalkane is fluoroalkyl, chloroalkyl, bromoalkyl, and iodoalkyl.

The method comprises the following steps: the inorganic base is potassium hydroxide (preferably), sodium hydroxide and cesium hydroxide, and the organic base is sodium methoxide, sodium ethoxide and potassium tert-butoxide; the alkyl iodide is methyl iodide (preferably), ethyl iodide, 1, 2-diiodomethane, and methyl bromide.

As a further improvement of the synthesis method of benzo [ b ] naphtho [2,3-d ] thiophene of the present invention, in step 2):

the nitrite is sodium nitrite (preferred) and potassium nitrite;

the iodinated inorganic salt is potassium iodide, sodium iodide, and cesium iodide.

As a further improvement of the synthesis method of benzo [ b ] naphtho [2,3-d ] thiophene of the invention, the oxidizing agent in step 3) is a peroxide (preferred), persulfate, potassium dichromate, potassium permanganate, chlorate. The peroxide is hydrogen peroxide.

As a further improvement of the synthesis method of benzo [ b ] naphtho [2,3-d ] thiophene of the present invention, in the step 4):

s5 is 1-naphthalene boric acid;

the weak base (inorganic weak base) is potassium carbonate (preferred), sodium carbonate, sodium bicarbonate.

As a further improvement of the synthesis method of benzo [ b ] naphtho [2,3-d ] thiophene of the present invention, the organic solvent in the step 4) is toluene, tetrahydrofuran, dioxane, dimethyl sulfoxide, dimethyl ether.

As a further improvement of the synthetic method of benzo [ b ] naphtho [2,3-d ] thiophene of the present invention: the alcohol solution in step 5) is 25 to 35% (vol%) ethanol solution.

As a further improvement of the synthetic method of benzo [ b ] naphtho [2,3-d ] thiophene of the present invention:

the post-treatment of the step 1) is as follows: extracting and drying the obtained reaction liquid to obtain 2- (methylthio) aniline (S2);

the post-treatment of the step 2) is as follows: extracting and drying the obtained reaction liquid to obtain (2-iodophenyl) (methyl) sulfane (S3);

the post-treatment of the step 3) is as follows: extracting and drying the obtained reaction liquid to obtain 1-iodo-2- (methylsulfinyl) benzene (S4);

the post-treatment of the step 4) is as follows: extracting and purifying the obtained reaction liquid; obtaining 1- (2- (methyl sulfoxide phenyl)) naphthalene (S6);

the post-treatment of the step 5) is as follows: the obtained reaction liquid is cooled, crystallized and dried to obtain benzo [ b ] naphtho [2,3-d ] thiophene (T1).

In the invention, the following components are added: the dripping time is about 10-30 min.

The synthetic route of the invention is as follows:

the invention uses cheap and easily available raw material 2-aminobenzo [ d ] thiazole (S1), uses the raw material to prepare 2- (methylthio) aniline (S2) by ring opening under alkaline condition, and then carries out subsequent corresponding preparation, while the traditional preparation of methylthio compound uses mercaptan as raw material for alkylation, the preparation process has pungent odor, great toxicity and great harm in industrial production; the invention effectively overcomes the technical defects. In addition, the present invention uses thiocarbonyl reactant (S6) to close the ring to give the product (T1) in high yield.

The beneficial effects of the invention are as follows: compared with the existing synthetic scheme, the invention adopts a green environment-friendly route to obtain benzo [ b ] naphtho [2,3-d ] thiophene with high yield and high quality. The preparation method disclosed by the invention is simple, mild in condition, few in reaction byproducts, simple in post-treatment, high in yield and purity, belongs to the field of green chemistry, and is easy for industrial production.

Detailed Description

The invention will be further described with reference to the following specific examples, but the scope of the invention is not limited thereto:

in the following cases:

concentrated hydrochloric acid refers to an aqueous HCl solution with a mass concentration of 37%.

Sulfuric acid means H with a mass concentration of 98.3% ₂ SO ₄ 。

The correctness of the results obtained by each step of each example below was characterized by NMR.

Not explicitly stated, all represent at room temperature (20-25 ℃).

The dripping time is about 5-30 min.

Example 1 Synthesis of benzo [ b ] naphtho [2,3-d ] thiophene,

the synthetic route is as follows:

the following steps are sequentially carried out:

(1) 100mL of water and 1.34mol (about 74.8 g) of potassium hydroxide were added to a glass reaction flask, dissolved with stirring, and cooled to room temperature; 0.067mol (about 10 g) of commercially available 2-aminobenzo [ d ] thiazole (S1) was added, and the mixture was heated to reflux (about 100 ℃ C.) and stirred for reaction for 12 hours; then cooled to room temperature, 0.08mol (11.35 g) of methyl iodide was added dropwise thereto and the reaction was continued with stirring for 2 hours, at which point the end point of the reaction was detected by a spot plate.

The time for dropping methyl iodide is about 10 to 20 minutes.

The resulting reaction was left to stand for separation and the lower oil was extracted with ethyl acetate (200 mL) and water (3 x 300 mL), the ethyl acetate phase was taken, the solvent was removed (i.e. ethyl acetate was removed) to give 8.9g (0.064 mol) of the product 2- (methylthio) aniline (S2) in about 95.4% yield.

(2) Mixing 0.17mol (about 14 mL) of concentrated hydrochloric acid with 14mL of water to obtain a hydrochloric acid solution; mixing 0.06mol (about 8.9 g) of 2- (methylthio) aniline (S2) with 55mL of acetone to obtain an acetone solution of 2- (methylthio) aniline (abbreviated as S2/acetone); 0.07mol (about 5 g) of sodium nitrite is dissolved in 11mL of water to obtain an aqueous solution of sodium nitrite; 0.13mol (about 21.2 g) of potassium iodide was dissolved in 75mL of water to obtain an aqueous potassium iodide solution;

the hydrochloric acid solution is cooled to 0 ℃, S2/acetone is added dropwise (the dropwise adding time is about 10 min), the temperature is reduced to-40 ℃, the sodium nitrite aqueous solution is added dropwise (the dropwise adding time is about 20 min), the temperature is kept at-40 ℃ and the mixture is stirred for 0.75h, then the potassium iodide aqueous solution is added dropwise (the dropwise adding time is about 30 min), and the reaction is carried out for 1h at room temperature after the dropwise adding. At this time, the spot plate detects the end point of the reaction.

The reaction mixture was allowed to stand to separate, and the organic layer obtained by separating was washed with a saturated aqueous sodium bisulfate solution (2×50 mL), extracted with dichloromethane (200 mL) and water (3×300 mL), the organic layer was taken, the solvent was dried by spin drying, and washed with petroleum ether (2×100 mL), followed by conventional drying, to obtain 13g (0.052 mol) of (2-iodophenyl) (methyl) sulfane (S3). The yield was about 86.7%.

(3) 0.052mol (about 13 g) of S3 and 195mL of glacial acetic acid are mixed at 0 ℃, 0.06mol of hydrogen peroxide (30% by mass) is added dropwise and stirred at room temperature for 12 hours, and at this time, the end point of the reaction is detected by a spot plate.

The resulting reaction solution was freed from glacial acetic acid, extracted with dichloromethane (200 mL) and water (3 x 300 mL), the organic phase was taken and the solvent was removed to give 13.2g (0.0496 mol) of 1-iodo-2- (methylsulfinyl) benzene (S4) in about 95.39% yield.

(4) 0.23mol (about 32.2 g) of potassium carbonate was dissolved in 115mL of water to obtain a potassium carbonate solution;

0.037mol (about 10 g) of S4, 0.038mol (about 6.65 g) of commercially available S5 were added to 38mL of tetrahydrofuran, followed by dropwise addition of a potassium carbonate solution (dropwise addition time: about 5 min), 0.1g of tetrakis (triphenylphosphine) palladium was added under nitrogen, and the mixture was heated at 70℃under nitrogen and reacted overnight (12 h).

The resulting reaction solution was extracted with dichloromethane (200 mL) and water (3×300 mL), the solvent was removed from the organic phase, toluene (100 mL) was used to recrystallize the obtained solid, and 8.5g (0.032 mol) of 1- (2- (methylsulfonylphenyl)) naphthalene (S6) was obtained after suction filtration, with a yield of about 86%.

(5) 0.013mol (about 3.5 g) of S6 is added into 0.2mol of sulfuric acid in batches at the temperature of 0-5 ℃, the mixture is stirred for 2 hours at room temperature, the reaction solution is poured into 100mL of ice water, the saturated potassium carbonate solution is added to adjust the pH to 8, the mixture is heated and refluxed for 1 hour, then 30mL of 30% ethanol solution is added, and the mixture is refluxed for 0.5 hour.

The reaction mixture was cooled to room temperature, and a yellow solid was precipitated, which was suction-filtered and dried (50 ℃ C.) to obtain 2.88g (0.123 mol) of benzo [ b ] naphtho [2,3-d ] thiophene (T1) as a target product in a yield of about 94.67%.

The batch is divided into two batches with an interval of about 30 minutes.

Example 2, synthesis of benzo [ b ] naphtho [2,3-d ] thiophene the following steps were performed in order:

(1) 200mL of water and 2.68mol of potassium hydroxide are added into a glass reaction bottle, stirred for dissolution and cooled to room temperature; 0.133mol of commercially available S1 was added thereto, and the mixture was heated to reflux and stirred for 12 hours. Then cooled to room temperature, 0.16mol of methyl iodide was added dropwise, and the end point of the reaction was detected by a spot plate.

The reaction mixture was allowed to stand to separate, and the oily substance in the lower layer was extracted with ethyl acetate and water, and the ethyl acetate phase was taken and the solvent was removed to obtain 18g (0.13 mol) of 2- (methylthio) aniline (S2) as a product in a yield of about 97.7%.

(2) Mixing 0.34mol of concentrated hydrochloric acid with 28mL of water to obtain a hydrochloric acid solution; mixing 0.13mol of 2- (methylthio) aniline (S2) with 111mL of acetone to obtain S2/acetone; dissolving 0.14mol of sodium nitrite in 22mL of water to obtain an aqueous solution of sodium nitrite; dissolving 0.26mol of potassium iodide in 130mL of water to obtain a potassium iodide aqueous solution;

cooling the hydrochloric acid solution to 0 ℃, dropwise adding S2/acetone, cooling to-40 ℃, dropwise adding an aqueous solution of sodium nitrite, preserving heat at-40 ℃ and stirring for 0.75h, dropwise adding an aqueous solution of potassium iodide, and reacting for 1h at normal temperature after dropwise adding. At this time, the spot plate detects the end point of the reaction.

The reaction solution was allowed to stand for separation, and the organic layer obtained by separating was washed with a saturated aqueous sodium bisulfate solution, extracted with methylene chloride and water, the organic layer was taken out, the solvent was spin-dried, and washed with petroleum ether to obtain (2-iodophenyl) (methyl) sulfane (S3) 0.112mol in about 86.15% yield.

(3) At 0 ℃, 0.096mol of S3 and 360mL of glacial acetic acid are mixed, 0.11mol of hydrogen peroxide (30% by mass) is added dropwise, and the mixture is stirred for 12 hours at room temperature, and at the moment, the end point of the reaction is detected by a dot plate.

The resulting reaction solution was subjected to removal of glacial acetic acid, extraction with methylene chloride and water, and the organic phase was taken and the solvent was removed to obtain 1-iodo-2- (methylsulfinyl) benzene (S4) in a yield of about 94.7%.

(4) 0.46mol of potassium carbonate is dissolved in 233mL of water to obtain a potassium carbonate solution;

0.074mol of S4 and 0.076mol of commercially available S5 were added to 77mL of tetrahydrofuran, and then a potassium carbonate solution was added dropwise thereto, 0.2g of tetrakis (triphenylphosphine) palladium was added under nitrogen atmosphere, and the mixture was heated at 70℃under nitrogen atmosphere to react overnight (12 hours).

The obtained reaction solution was extracted with methylene chloride and water, the solvent was removed from the organic phase, and toluene was used for recrystallization to obtain a solid, which was suction-filtered to obtain 16.26g of 1- (2- (methylsulfonylphenyl)) naphthalene (S6) in a yield of about 82.5%.

(5) 0.026mol of S6 is added into 0.4mol of sulfuric acid in batches at the temperature of 0-5 ℃, the mixture is stirred for 2 hours at room temperature, the reaction solution is poured into 200mL of ice water, the pH is adjusted to 8 by adding saturated potassium carbonate solution, the mixture is heated and refluxed for 1 hour, 60mL of 30% ethanol is added, and the mixture is refluxed for 0.5 hour.

The reaction mixture was cooled to room temperature, and a yellow solid was precipitated, which was suction-filtered and dried to obtain 5.62g of benzo [ b ] naphtho [2,3-d ] thiophene (T1) as a target product in a yield of about 92.3%.

Example 3, synthesis of benzo [ b ] naphtho [2,3-d ] thiophene the following steps were performed in sequence:

(1) 1000mL of water and 13.4mol of potassium hydroxide were added to a glass reaction flask, dissolved with stirring, and cooled to room temperature. 0.666mol of commercially available S1 was added thereto, and the mixture was heated to reflux and stirred for 12 hours. Then cooled to room temperature, 0.8mol of methyl iodide is added dropwise, and the reaction is continued with stirring for 2 hours, at which point the endpoint of the reaction is detected by a point plate.

The reaction mixture was allowed to stand to separate, the lower oily substance was extracted with ethyl acetate and water, the ethyl acetate phase was taken, and the solvent was removed to obtain 0.65mol of 2- (methylthio) aniline (S2) as a product, and the yield was about 97.6%.

(2) Mixing 1.7mol of concentrated hydrochloric acid with 135mL of water to obtain a hydrochloric acid solution; mixing 0.65mol of 2- (methylthio) aniline (S2) with 550mL of acetone to obtain S2/acetone; 0.7mol of sodium nitrite is dissolved in 100mL of water to obtain sodium nitrite aqueous solution; 1.3mol of potassium iodide is dissolved in 500mL of water to obtain a potassium iodide aqueous solution;

The reaction solution was allowed to stand for separation, and the organic layer obtained by separating was washed with a saturated aqueous sodium bisulfate solution, extracted with methylene chloride and water, the organic layer was taken, the solvent was spin-dried, and washed with petroleum ether to obtain (2-iodophenyl) (methyl) sulfane (S3) 0.576mol in about 88.6% yield.

(3) At 0 ℃, 0.576mol of S3 and 1800mL of glacial acetic acid are mixed, 0.638mol of hydrogen peroxide (30% by mass) is added dropwise, and the mixture is stirred for 12 hours at room temperature, and at the moment, the end point of the reaction is detected by a spot plate.

The resulting reaction solution was subjected to removal of glacial acetic acid, extraction with methylene chloride and water, and the organic phase was taken and the solvent was removed to obtain 0.547mol of 1-iodo-2- (methylsulfinyl) benzene (S4), with a yield of about 94.96%.

(4) 1.4mol of potassium carbonate is dissolved in 700mL of water to obtain a potassium carbonate solution;

0.225mol of S4 and 0.23mol of commercially available S5 were added to 250mL of tetrahydrofuran, followed by dropwise addition of a potassium carbonate solution, 0.6g of tetrakis (triphenylphosphine) palladium was added under nitrogen, and the mixture was heated at 70℃under nitrogen to react overnight (12 h).

The obtained reaction solution was extracted with methylene chloride and water, the solvent was removed from the organic phase, and toluene was used for recrystallization to obtain a solid, which was suction-filtered to obtain 0.195mol of 1- (2- (methylsulfonylphenyl)) naphthalene (S6) in a yield of about 86.67%.

(5) 0.113mol of S6 is added into 1.72mol of sulfuric acid in batches at the temperature of 0-5 ℃, the room temperature is restored, the mixture is stirred for 2 hours, the reaction solution is poured into 500mL of ice water, the saturated potassium carbonate solution is added to adjust the pH to 8, after heating and refluxing for 1 hour, 250mL of 30% ethanol is added, and the reflux is carried out for 0.5 hour.

The reaction mixture was cooled to room temperature, a yellow solid was precipitated, and the resulting product was suction-filtered and dried to give 0.107mol of benzo [ b ] naphtho [2,3-d ] thiophene (T1) as a target product in a yield of about 94.69%.

Example 4, the potassium hydroxide of example 1, step 1), was changed to other bases as described in Table 1, the molar amount was kept constant, still 1.34mol, the remainder being identical to step 1) of example 1. The corresponding yields of 2- (methylthio) aniline (S2) are shown in table 1 below.

TABLE 1

Example 5, the methyl iodide in step 1) of example 1 was changed to other haloalkanes as described in table 2, the molar amount was kept constant, still at 0.08mol, and the rest was identical to step 1) of example 1. The corresponding yields of 2- (methylthio) aniline (S2) are shown in table 2 below.

TABLE 2

Example 6, replacing sodium nitrite in step 2) of example 1 with potassium nitrite, the molar amount still being 0.07mol, the remainder being identical to step 2) of example 1, yields (2-iodophenyl) (methyl) sulfane (S3) of about 64%.

Example 7, replacing the potassium iodide of step 2) of example 1 with sodium iodide, the molar amount still being 0.13mol, the remainder being identical to step 2) of example 1, the yield of (2-iodophenyl) (meth) sulfane (S3) obtained being about 67%.

Example 8, replacing the hydrogen peroxide in step 3) of example 1 with an oxidant as described in table 3, the molar amount still being 0.06mol, the remainder being identical to step 3) of example 1; the corresponding yields of 1-iodo-2- (methylsulfinyl) benzene (S4) are shown in table 3 below:

TABLE 3 Table 3

Example 9, the tetrahydrofuran in step 4) of example 1 was replaced with an organic solvent as described in table 4, the volume amount was kept unchanged, and the rest was the same as that of step 4) of example 1, and the yields of 1- (2- (methylsulfonylphenyl)) naphthalene (S6) were obtained as shown in table 4 below:

TABLE 4 Table 4

Example 10, replacing the potassium carbonate of example 1, step 4) with an inorganic weak base as described in Table 5, still in an amount of 0.23mol, the remainder being identical to step 4) of example 1, yields of 1- (2- (methylsulfonylphenyl)) naphthalene (S6) as shown in Table 5 below:

TABLE 5

Finally, it should also be noted that the above list is merely a few specific embodiments of the present invention. Obviously, the invention is not limited to the above embodiments, but many variations are possible. All modifications directly derived or suggested to one skilled in the art from the present disclosure should be considered as being within the scope of the present invention.

Claims

1. The synthesis method of benzo [ b ] naphtho [2,3-d ] thiophene is characterized by comprising the following steps:

1) Adding 2-aminobenzo [ d ] thiazole into alkali liquor, heating and refluxing for 12-20 h, cooling to room temperature, dropwise adding haloalkane, and continuously stirring for 2-4 h; the obtained reaction liquid is subjected to post-treatment to obtain 2- (methylthio) aniline;

2-aminobenzo [ d ] thiazole: alkali: haloalkane=1, 18 to 20:1.2 molar ratio;

the alkali is potassium hydroxide; the haloalkane is methyl iodide;

2) Dropwise adding an acetone solution of 2- (methylthio) aniline into a hydrochloric acid solution at 0-5 ℃, then cooling to-50 to-40 ℃, dropwise adding a nitrite aqueous solution, and carrying out heat preservation reaction for 0.5-3 h; then adding aqueous solution of iodized inorganic salt dropwise, then reacting for 1-1.5 hours at room temperature, and performing post-treatment on the obtained reaction liquid to obtain (2-iodophenyl) (methyl) sulfane;

2- (methylthio) aniline: nitrite: iodinated inorganic salts: hydrochloric acid=1:1 to 1.5:2 to 2.5:2.5 to 3 molar ratio;

the nitrite is sodium nitrite, and the iodized inorganic salt is potassium iodide;

3) Adding (2-iodophenyl) (methyl) sulfane at 0-5 DEG CAcetic acidAdding an oxidant, stirring at room temperature for 12-20 h, and performing post-treatment on the obtained reaction liquid to obtain 1-iodo-2- (methylsulfinyl) benzene;

(2-iodophenyl) (methyl) sulfane: oxidant = 1:1 to 5 molar ratio;

the oxidant is hydrogen peroxide;

4) Dissolving 1-iodine-2- (methylsulfinyl) benzene and a compound S5 in an organic solvent, adding a weak base aqueous solution, adding a catalyst under the protection of inert gas, reacting for 12-20 hours at 70+/-10 ℃, and performing post-treatment on the obtained reaction solution to obtain 1- (2- (methylsulfoxide phenyl)) naphthalene;

the compound S5 is 1-naphthalene boric acid; the catalyst is tetra (triphenylphosphine) palladium;

1-iodo-2- (methylsulfinyl) benzene: compound S5: weak base=1:1 to 1.5:1 to 8 molar ratio;

the weak base is potassium carbonate;

5) Adding 1- (2- (methyl sulfoxide phenyl)) naphthalene into sulfuric acid at a low temperature of 0-5 ℃, stirring for 2+/-0.5 h at room temperature, pouring into ice water, adjusting the pH value to 8-8.5, heating and refluxing for 1-6 h, adding an alcohol solution and refluxing for 0.5-2 h, and performing aftertreatment on the obtained reaction solution to obtain benzo [ b ] naphtho [2,3-d ] thiophene;

1- (2- (methylsulfonylphenyl)) naphthalene: sulfuric acid=1:15 to 18 molar ratio;

the alcohol solution is 25-35% ethanol solution; % is volume%.

2. The method for synthesizing benzo [ b ] naphtho [2,3-d ] thiophene according to claim 1, wherein:

the organic solvent in the step 4) is toluene, tetrahydrofuran, dioxane, dimethyl sulfoxide and dimethyl ether.

3. The synthesis method of benzo [ b ] naphtho [2,3-d ] thiophene according to claim 1 or 2, wherein:

the post-treatment of the step 1) is as follows: extracting and drying the obtained reaction liquid to obtain 2- (methylthio) aniline;

the post-treatment of the step 2) is as follows: extracting and drying the obtained reaction liquid to obtain (2-iodophenyl) (methyl) sulfane;

the post-treatment of the step 3) is as follows: extracting and drying the obtained reaction liquid to obtain 1-iodo-2- (methylsulfinyl) benzene;

the post-treatment of the step 4) is as follows: extracting and purifying the obtained reaction liquid; obtaining 1- (2- (methyl sulfoxide phenyl)) naphthalene;

the post-treatment of the step 5) is as follows: the obtained reaction liquid is cooled, crystallized and dried to obtain benzo [ b ] naphtho [2,3-d ] thiophene.