CN104926784B - Functionalisable hexyl thiophene class compound of one class side chain terminal and preparation method thereof - Google Patents

Abstract

The invention discloses a hexylthiophene compound capable of functionalizing a side chain terminal and a preparation method thereof, belonging to the technical field of organic photoelectric functional materials. Such compounds have the following structures: Wherein, X is Cl, Br, I, p-methoxyphenoxy, C1-C6 alkylsilyloxy, etc. Using 2,5-dibromothiophene as a raw material, it is firstly synthesized by Friedel-Crafts acylation reaction to add hexyl side chain, then halogen atom protection group side chain terminal functional group, then Huang Minglong reaction to reduce carbonyl group, and finally remove the protection group. The synthetic route has cheap and easy-to-obtain raw materials, simple and easy reaction conditions, is suitable for mass production, and the products are easy to separate and purify, and can simultaneously obtain a series of hexylthiophene compounds that can be functionalized at the end of the side chain. The compound can be used as a synthetic reaction building block of a multifunctional polymer or a macromolecular photoelectric functional material.

Description

A class of hexylthiophene compounds that can be functionalized at the end of the side chain and its preparation method

technical field

The invention belongs to the technical field of organic photoelectric functional materials, in particular to a class of hexylthiophene compounds whose side chain terminals can be functionalized and a preparation method thereof.

Background technique

In recent years, since the functionalization of side chains can endow polymers or macromolecular optoelectronic functional materials with excellent properties, the synthesis of organic optoelectronic functional materials based on side chain terminal functionalization has attracted people's attention. This is because the functionalization of this type of material can minimize the impact of the introduction and reaction of functional groups on the photoelectric properties of the material, and can also endow the material with new functions and values. For example: by introducing crosslinking groups, the preparation of multilayer organic optoelectronic devices can be realized (U.S.Pat. Appl. Publ. 2015, US 20150075622 A1 20150319; ACS Nano, 2015, 9, 371-377; 2015, 7, 452-459) or improve device stability and lifetime (Macromolecules, 2009, 42, 1610-1618; J. Mater. Chem. C., 2014, 2,7163-7167; Adv. Funct. Mater ., 2009, 19, 2273-2281); by introducing special functional groups, dangerous goods such as explosives (Chemical Communications, 2015, 51, 7207), heavy metal ions (ACS Applied Material & Interfaces, 2015, 7, 6882-6888) etc. The convenient and rapid detection of materials or the function of endowing materials with biological probes (ACS Applied Materials & Interfaces, 2015, 7, 3189-3198; Chemical Science, 2015, 6, 1825-1831)). Hexylthiophene-based organic optoelectronic functional materials are one of the most important types. However, as an important intermediate in the synthesis of hexylthiophene-based organic optoelectronic functional materials, there are few reports on the synthesis methods of hexylthiophene-based compounds that can be functionalized at the end of the side chain. . There are only two reports on the synthesis of 2,5-dibromo-3-bromohexylthiophene: one uses 3-bromothiophene as a raw material, anhydrous and oxygen-free at -78 °C, first by butyllithium Debromination generates negative ions, then reacts with 1,6-dibromohexyl to directly obtain 3-bromohexylthiophene, and finally brominates to generate the target product. Although the synthesis route of this method is short, because the stability of the 3-position anion is poorer than that of the 2-position, it is difficult to avoid the generation of 2-(6-bromohexyl)thiophene in the final reaction product, and the two products The performance is similar, and it is difficult to obtain a certain compound with high purity; in addition, the reaction conditions are harsh, and it needs to be carried out under strict anhydrous and oxygen-free ultra-low temperature conditions, which is not suitable for large-scale production. Another method first uses p-methoxyphenol to protect one end of 1,6-dibromohexane, then uses Kumada coupling reaction to couple it with 3-bromothiophene, then deprotects and brominates to obtain the target product. This method can obtain high-purity target products, which is beneficial to further reactions to obtain high-molecular-weight polymers or high-purity macromolecular compounds. However, the synthetic route is relatively long, and 1,6-dibromohexane, which is protected at one end, needs to pass through multiple times. It can only be obtained by the recrystallization of the Grignard reagent. It is difficult to determine the concentration of the final Grignard reagent during the preparation of the Grignard reagent, and the preparation of the Grignard reagent and the Kumada coupling reaction also require strict anhydrous and oxygen-free operations, which is not easy to achieve.

In summary, the existing hexylthiophene compounds that can be functionalized at the end of the side chain are limited, only 2,5-dibromo-3-bromohexylthiophene, and the synthesis method or reaction conditions are harsh and difficult to purify. Difficult to industrialize.

Contents of the invention

The purpose of the present invention is to provide a method for preparing a series of functionalized hexylthiophenes at the end of the side chain with simple operation, easy purification, high yield, easy industrialization and low cost; Can functionalize hexylthiophenes.

In order to achieve the purpose of the present invention, the present invention uses 2,5-dibromothiophene and 6-halohexanoyl chloride as raw materials, adopts classical Friedel-Crafts acylation reaction conditions, and can simultaneously obtain two kinds of hexylthiophenes that can be functionalized at the end of the side chain Compounds 2,5-dibromo-3-(6-halohexanoyl)thiophene and 2-bromo-5-(6-halohexanoyl)thiophene; respectively protect the terminal halogen atoms with ROH to obtain two kinds of functionalized hexylthiophene These two compounds can be used to synthesize precursors of polymer monomers or macromolecular compounds respectively, and then deprotect after reaction to enhance the suitability of the reaction substrate; then use the Huang Minglong reaction to reduce the carbonyl group to obtain two new Hexylthiophene compounds with strong adaptability can also be used for polymer synthesis monomers or macromolecular compound synthesis precursors, and then deprotected after reaction; after deprotection, two kinds of hexylthiophenes that can be functionalized at the end of the side chain can be obtained Compounds 2,5-dibromo-3-halohexylthiophene and 2-bromo-5-halohexylthiophene. The reaction formula is as follows:

Wherein, X is Cl, Br, I, R is p-methoxyphenyl, C1-C6 alkylsilyl.

The specific preparation method is as follows:

(1) Synthesis of 2,5-dibromo-3-(6-halohexanoyl)thiophene (compound 1) and 2-bromo-5-(6-halohexanoyl)thiophene (compound 2)

Add 2,5-dibromothiophene, organic aprotic solvent and 6-halocaproyl chloride into the reactor, stir and cool to -5~5°C, add Lewis acid in batches, after the addition, naturally rise to room temperature, and react at room temperature. The reaction solution was slowly poured into ice dilute hydrochloric acid solution to quench the reaction, washed with water, extracted, dried, and the solvent was removed by rotary evaporation, and separated by silica gel column chromatography to obtain compound 1 as a yellow viscous liquid and compound 2 as a yellow solid. Organic aprotic solvents are dichloromethane, carbon disulfide or chloroform. The 6-halogenohexanoyl chloride is selected from 6-chlorohexanoyl chloride, 6-bromohexanoyl chloride or 6-iodohexanoyl chloride;

(2) Synthesis of 2,5-dibromo-3-(6-Roxyhexanoyl)thiophene (compound 3) and 2-bromo-5-(6-p-Roxyhexanoyl)thiophene (compound 4)

Add p-methoxyphenol or alkylsilanol, potassium carbonate, 18-crown-6, acetonitrile, compound 1 or 2 into the reaction flask, and reflux overnight. Add water to quench the reaction, extract, and separate by silica gel column chromatography to obtain product 3 or 4 as a yellow solid.

(3) Synthesis of 2,5-dibromo-3-(6-Roxyhexyl)thiophene (compound 5) and 2-bromo-5-(6-p-Roxyhexyl)thiophene (compound 6)

Add compound 3 or compound 4, potassium hydroxide, hydrazine hydrate, and diethylene glycol into the reactor, react overnight at 190-200 ° C, add water to quench the reaction, extract, and separate by column chromatography to obtain yellow solid product compound 5 or Compound 6.

(4) Synthesis of 2,5-dibromo-3-(6-halohexyl)thiophene (compound 7) and 2-bromo-5-(6-halohexyl)thiophene (compound 8)

Add hydrohalic acid, glacial acetic acid and compound 5 or 6 into the reaction bottle, and the resulting mixture is stirred and reacted at 90-100°C. Add water to quench the reaction, extract, neutralize, dry, and separate by column chromatography to obtain liquid product 7 or 8. The hydrohalic acid is HCl, HI or HBr.

In the step (1), the molar ratio of 2,5-dibromothiophene to 6-halocaproyl chloride is 1:1˜1:1.2.

The Lewis acid in the step (1) is aluminum chloride, ferric chloride and the like.

The 6-halogenohexanoyl chloride in the step (1) is preferably 6-bromohexanoyl chloride or 6-iodohexanoyl chloride.

In the step (2), the molar ratio of compound 1 or compound 2, p-methoxyphenol or alkyl silanol, and potassium carbonate is 1:2:2.2˜1:2.4:4.8.

The volume ratio of compound 3 or 4 and potassium hydroxide to hydrazine hydrate in the step (3) is 1:10:5-1:50:10.

In the step (4), the molar ratio of compound 5 or 6, hydrohalic acid, and glacial acetic acid is 1:5:2˜1:6:3.

Beneficial effects of the present invention: the present invention first designs a new class of 3-hexylthiophene compounds that can be functionalized at the end of the side chain. application range. For example, by introducing crosslinking groups, the preparation of multilayer organic photoelectric devices can be realized or the stability and service life of the devices can be improved; by introducing special functional groups, it can be realized that dangerous goods such as explosives, heavy metal ions, etc. The role of the probe. In addition, the present invention provides a preparation method of 3-hexylthiophene compounds with simple operation, easy purification, high yield, easy industrialization and low cost, which can be functionalized at the end of the side chain, which can promote new high-performance organic photoelectric functions Material development and application research.

detailed description

The following examples help to understand the present invention, but are not limited to the content of the present invention.

Example 1

(1) Synthesis of 2,5-dibromo-3-(6-halohexanoyl)thiophene (compound 1) and 2-bromo-5-(6-halohexanoyl)thiophene (compound 2)

Add 0.01 mol of 2,5-dibromothiophene to the reactor, then add 80-160 mL of dichloromethane and 0.01 mol of 6-bromohexanoyl chloride, stir for 30 min, cool to -5 °C, and add 0.01 mol of Aluminum chloride, naturally rose to room temperature after adding, and reacted at room temperature for 3 to 6 hours. Slowly pour the reaction solution into ice dilute hydrochloric acid solution to quench the reaction, wash with water, extract with CH ₂ Cl ₂ , dry over anhydrous Na ₂ SO ₄ , remove the solvent by rotary evaporation, separate by silica gel column chromatography, eluent: petroleum ether: acetic acid Ethyl ester=30:1, compound 1 and compound 2 in yellow viscous liquid were obtained. Compound 1: EI-MS m/z (%) : 419(M ⁺ , 0.68), 284 (Base Peak, 100%); ¹ H NMR (CDCl3): δ 7.11 (s, 1H), 3.45 (t, J = 6.8 Hz, 2H), 3.02 (t, J = 7.2 Hz, 2H), 1.93 (m, 2H), 1.78 (m, 2H), 1.56 (m,2H); ¹³ C NMR: 191.35, 140.87, 135.83, 121.57, 113.06, 41.08, 33.56, 32.55,27.71, 23.04; FT-IR: (KBr): ν(cm ^-1 ) 3087, 2930, 2850, 1650, 1495, 1408, 1192,991, 825, 724; elemental analysis : Calculated for C ₁₀ H ₁₁ Br ₃ OS: C, 28.67; H, 2.65; Br, 57.21; O, 3.82; S, 7.65; Found: C, 28.91; H, 2.75; Br, 57.05; . Compound 2: EI-MS m/z (%) : 340 (M ⁺ , 4.28), 206 (Base Peak, 100%); ¹ H NMR (CDCl3): δ 7.46 (d, J =4 Hz, 1H) , 7.12 (d, J = 4 Hz, 1H), 3.45 (t, J = 6.8 Hz, 2H), 3.02 (t, J = 6.8Hz, 2H), 1.95 (m, 2H), 1.74 (m, 2H) , 1.54 (m, 2H); ¹³ C NMR: 191.86, 145.77,131.83, 131.24, 122.52, 38.42, 33.53, 32.53, 27.80, 23.58; FT-IR: (KBr): ν(cm ^-1 ) 3084, 2943, 1655, 1405, 1255, 1202, 921, 823, 724; Elemental Analysis: Calculated for C ₁₀ H ₁₁ Br ₃ OS: C, 35.32; H, 3.56; Br, 46.99; O, 4.70; S, 9.43; : C, 35.29; H, 3.54; Br, 46.76; S, 9.79.

(2) Synthesis of 2,5-dibromo-3-(6-Roxyhexanoyl)thiophene (compound 3) and 2-bromo-5-(6-p-Roxyhexanoyl)thiophene (compound 4)

Add 0.02 mol of p-methoxyphenol, 0.024 mol of potassium carbonate, catalytic amount of 18-crown-6, 100 mL of acetonitrile, and 0.01 mol of compound 1 or 2 into the reaction flask, and reflux overnight. The reaction was quenched by adding water, extracted with dichloromethane, separated by silica gel column chromatography, eluent: petroleum ether: ethyl acetate = 30:1, and the product 3 or 4 was obtained as a yellow solid. Compound 3: EI-MSm/z (%) : 462 (M ⁺ , 10.18), 269 (Base Peak, 100%); ¹ H NMR (CDCl3): δ 7.11 (s,1H), 6.04 (s, 4H) , 3.96 (t, J = 6.4 Hz, 2H), 3.79 (s, 3H), 3.05 (t, J = 7.2Hz, 2H), 1.85 (m, 4H), 1.58 (m, 2H); ¹³ C NMR: 192.16, 153.77, 153.19, ^145.87 , 131.81, 131.22, 122.44, 115.46, 114.66, 68.30, 55.77, 38.61, 29.20, 24.32, 20.78; 1651, 1507, 1421, 1231, 1180, 1030, 817, 737; Elemental Analysis: Calculated for C ₁₀ H ₁₁ Br ₃ OS: C, 44.18; H, 3.93; Br, 34.58; O, 10.38; S, 6.94; Measured values: C, 45.35; H, 4.09; Br, 34.35; S, 6.62. Compound 4: EI-MSm/z (%) : 383 (M ⁺ , 3.63), 191 (Base Peak, 100%); ¹ H NMR (CDCl3): δ 7.46 (d, J = 4 Hz, 1H), 7.12 (d, J = 4 Hz, 1H), 6.84 (s, 4H), 3.94 (t, J = 6.4 Hz, 2H), 3.79 (s, 3H), 2.88 (t, J = 7.6 Hz, 2H), 1.82 (m, 4H), 1.57 (m, 2H); ¹³ C NMR: 191.57, 153.77, 153.21, 140.93, 135.84, 121.44, 115.47, 114.66, 113.02,68.33, 55.77, 41.25, 29.23, 25.74, 23.72; FT-IR: (KBr): ν(cm ^-1 ) 3098, 2936,2842, 1644, 1512, 1408, 1238, 1048, 9,06, 742; Elemental Analysis: Calculated, C ₁₀ H ₁₁ Br ₃ OS:C, 53.27; H, 5.00; Br, 20.85; O, 12.52; S, 8.37; Found: C, 53.02; H, 4.92;Br, 20.52;

(3) Synthesis of 2,5-dibromo-3-(6-Roxyhexyl)thiophene (compound 5) and 2-bromo-5-(6-p-Roxyhexyl)thiophene (compound 6)

Add 0.01 mol of compound 3 or compound 4, 0.10 mol of potassium hydroxide, 5 mL of hydrazine hydrate, and 50 mL of diethylene glycol into the reactor, react overnight at 190°C, add water to quench the reaction, extract with dichloromethane, and column Analysis and separation gave compound 5 or compound 6 as a yellow solid product.

(4) Synthesis of 2,5-dibromo-3-(6-halohexyl)thiophene (compound 7) and 2-bromo-5-(6-halohexyl)thiophene (compound 8)

Add 0.05 mol of hydrohalic acid (48% by mass), 0.02 mol of glacial acetic acid and 0.01 mol of compound 5 or 6 into the reaction flask, and stir the resulting mixture at 100 °C for 1-2 days. Add water to quench the reaction, extract with ether, neutralize with saturated sodium bicarbonate solution, dry over anhydrous sodium sulfate, separate by column chromatography, eluent: n-hexane, and obtain liquid product 7 or 8. The hydrohalic acid is HCl, HI or HBr.

Example 2

(1) Synthesis of 2,5-dibromo-3-(6-halohexanoyl)thiophene (compound 1) and 2-bromo-5-(6-halohexanoyl)thiophene (compound 2)

Add 0.02 mol of 2,5-dibromothiophene to the reactor, then add 160 mL of carbon disulfide and 0.024 mol of 6-iodohexanoyl chloride, stir for 60 min and cool to 5 °C, add 0.012 mol of ferric chloride in batches, After the addition, it was naturally raised to room temperature, and reacted at room temperature for 6 hours. Slowly pour the reaction solution into ice dilute hydrochloric acid solution to quench the reaction, wash with water, extract with CH ₂ Cl ₂ , dry over anhydrous Na ₂ SO ₄ , remove the solvent by rotary evaporation, separate by silica gel column chromatography, eluent: petroleum ether: acetic acid Ethyl ester=30:1, compound 1 and compound 2 in yellow viscous liquid were obtained.

(2) Synthesis of 2,5-dibromo-3-(6-Roxyhexanoyl)thiophene (compound 3) and 2-bromo-5-(6-p-Roxyhexanoyl)thiophene (compound 4)

Add 0.024 mol of triisopropylsilanol, 0.048 mol of potassium carbonate, catalytic amount of 18-crown-6, 200 mL of acetonitrile, and 0.01 mol of compound 1 or 2 into the reaction flask, and react under reflux overnight. The reaction was quenched by adding water, extracted with dichloromethane, separated by silica gel column chromatography, eluent: petroleum ether: ethyl acetate = 30:1, and the product 3 or 4 was obtained as a yellow solid.

(3) Synthesis of 2,5-dibromo-3-(6-Roxyhexyl)thiophene (compound 5) and 2-bromo-5-(6-p-Roxyhexyl)thiophene (compound 6)

Add 0.01 mol of compound 3 or compound 4, 0.50 mol of potassium hydroxide, 10 mL of hydrazine hydrate, and 100 mL of diethylene glycol into the reactor, react at 200°C overnight, add water to quench the reaction, extract with dichloromethane, and column layer Analysis and separation gave compound 5 or compound 6 as a yellow solid product.

(4) Synthesis of 2,5-dibromo-3-(6-halohexyl)thiophene (compound 7) and 2-bromo-5-(6-halohexyl)thiophene (compound 8)

Add 0.06 mol of hydrohalic acid (48% by mass), 0.03 mol of glacial acetic acid and 0.01 mol of compound 5 or 6 into the reaction flask, and stir the resulting mixture at 90°C for 1-2 days. Add water to quench the reaction, extract with ether, neutralize with saturated sodium bicarbonate solution, dry over anhydrous sodium sulfate, separate by column chromatography, eluent: n-hexane, and obtain liquid product 7 or 8. The hydrohalic acid is HCl, HI or HBr.

Claims (2)

1. the preparation method of the functionalized hexyl thiophene compound of a class of side chain end as following general formula, it is characterized in that, synthetic method is as follows: Wherein, X is Cl, Br, I; (1) Synthesis of 2,5-dibromo-3-(6-halohexanoyl)thiophene (compound 1) and 2-bromo-5-(6-halohexanoyl)thiophene (compound 2) Add 2,5-dibromothiophene, organic aprotic solvent and 6-halocaproyl chloride into the reactor, stir and cool to -5~5°C, add Lewis acid in batches, after the addition, naturally rise to room temperature, and react at room temperature; Slowly pour the reaction solution into ice dilute hydrochloric acid solution to quench the reaction, wash with water, extract, dry, remove the solvent by rotary evaporation, and separate by silica gel column chromatography to obtain compound 1 and compound 2; the organic aprotic solvent is dichloromethane or chloroform; The 6-halogenohexanoyl chloride is selected from 6-chlorohexanoyl chloride, 6-bromohexanoyl chloride or 6-iodohexanoyl chloride; (2) Synthesis of 2,5-dibromo-3-(6-Roxyhexanoyl)thiophene (compound 3) and 2-bromo-5-(6-Roxyhexanoyl)thiophene (compound 4) Add p-methoxyphenol or alkylsilanol, potassium carbonate, 18-crown-6, acetonitrile, compound 1 or 2 into the reaction flask, reflux reaction overnight; add water to quench the reaction, extract, and separate by silica gel column chromatography , to obtain compound 3 or 4; (3) Synthesis of 2,5-dibromo-3-(6-Roxyhexyl)thiophene (compound 5) and 2-bromo-5-(6-Roxyhexyl)thiophene (compound 6) Add compound 3 or compound 4, potassium hydroxide, hydrazine hydrate, and diethylene glycol into the reactor, react at 190-200°C overnight, add water to quench the reaction, extract, and separate by column chromatography to obtain compound 5 or compound 6; (4) Synthesis of 2,5-dibromo-3-(6-halohexyl)thiophene (compound 7) and 2-bromo-5-(6-halohexyl)thiophene (compound 8) Add hydrohalic acid, glacial acetic acid and compound 5 or 6 into the reaction flask, and stir the resulting mixture at 90-100°C for reaction; add water to quench the reaction, extract, neutralize, dry, and separate by column chromatography to obtain product 7 or 8; The hydrohalic acid is HCl, HI or HBr; In the step (1), the molar ratio of 2,5-dibromothiophene and 6-halocaproyl chloride is 1:1～1:1.2; In the step (2), the molar ratio of compound 1 or compound 2, p-methoxyphenol or alkyl silanol, and potassium carbonate is 1:2:2.2～1:2.4:4.8; In the step (3), the volume ratio of compound 3 or 4 and potassium hydroxide to hydrazine hydrate is 1:10:5-1:50:10; In the step (4), the molar ratio of compound 5 or 6, hydrohalic acid, and glacial acetic acid is 1:5:2˜1:6:3. 2 . The preparation method of hexylthiophene compound whose side chain terminal can be functionalized according to claim 1 , characterized in that: the Lewis acid in the step (1) is selected from aluminum chloride or ferric chloride. 3 .