A method for preparing carbazole alkyl phosphoric acid derivatives

Abstract

The invention provides a method for preparing a carbazole alkyl phosphate derivative. In the presence of an alkaline ionic liquid, a substitution reaction is carried out, thereby avoiding the use of an inorganic base as an acid-binding agent and a solvent in the prior art. No salt impurities are generated during the reaction, thereby improving atom economy and reducing production costs. The post-treatment is simple and the product yield is high.

Description

Technical Field

[0001] The invention relates to the technical field of organic synthesis, in particular to a method for preparing a carbazole butyl phosphate derivative. Background Art

[0002] Human demand for energy is constantly increasing, environmental pollution and greenhouse effect are becoming increasingly prominent, these problems have prompted scientists to develop clean and renewable energy. The development and utilization of solar energy has become a research hotspot in the field of new energy. There are many forms of solar energy utilization, and photoelectric conversion is the main form of effective utilization of solar cells. Solar cells are considered to be one of the most effective low-cost renewable clean energy sources, thereby achieving the goal of carbon neutrality.

[0003] In 1883, scientist Charles Fritts first produced solar cells that can directly convert solar energy into electrical energy. In the following century, scientists developed traditional photoelectric conversion materials such as silicon-based solar cells and compound solar cells. In 2009, Japanese scientist Miyasaka introduced the perovskite material MAPbI3 into solar cell devices. After nearly ten years of development, the efficiency of the cell has increased from the initial 3.8% to the current 25.5%, making perovskite solar cells a shining star of the new generation of solar cells due to their good photoelectric properties, high light absorption rate, simple preparation and large-area flexible preparation.

[0004] In recent years, SAMs self-assembled monolayer materials (carbazole derivatives with phosphonic acid anchoring groups, such as MeO-2PACz, 2PACz, Me-4PACz, Br-2PACz, TPA, EADR04) have been applied to solar cells due to their simple preparation, small parasitic absorption, low material consumption, and conformal coverage with the substrate, replacing classic hole transport layers such as PTAA and NiOX. The structures of some reported hole transport layer materials are as follows:

[0005]

[0006] The methods for preparing carbazole derivatives having phosphonic acid anchoring groups in the prior art include the following methods: CN115215901A and CN 114716476A disclose the following reaction routes:

[0007]

[0008] The above preparation method is easy to operate and does not require complicated processes and post-treatments. However, the yield of the last step of hydrolysis reaction is not high, which is not conducive to industrial production.

[0009] Ester Buchaca et al. (New J. Chem., 2010, 34, 2592-2598) conducted the final hydrolysis reaction under the conditions of trimethylsilyl iodide, dichloromethane and methanol, and the yield was increased to 82%.

[0010] It can be predicted that with the development of solar perovskite cells, the demand for the above compounds will increase greatly, and it is of great significance to develop new and efficient preparation methods of carbazole alkyl phosphate derivatives. Summary of the invention

[0011] The purpose of the present invention is to provide a method for preparing a carbazole alkyl phosphate derivative, so as to solve the technical problems existing in the prior art in the production of carbazole alkyl phosphate derivatives, such as high production cost, poor atom economy, low yield and purity, complex post-treatment and environmental disadvantages.

[0012] In order to solve the above technical problems, the present invention provides a method for preparing a carbazole alkyl phosphate derivative, and the reaction scheme is as follows:

[0013]

[0014] Wherein: X is independently selected from N, CR 1 ;

[0015] R 1 Each is independently selected from H, halogen, nitro, cyano, C1-C6 alkyl, C2-C6 alkenyl, C2-C6 alkynyl, C6-C 20 Aryl, C2-C 20 heteroaryl;

[0016] Or two adjacent R 1 Together with the carbon atom to which it is attached, it forms a 5-6 membered ring;

[0017] R is selected from C1-C6 alkyl, C2-C6 alkenyl, C2-C6 alkynyl, C6-C 20 Aryl, C2-C 20 heteroaryl;

[0018] n is an integer selected from 0 to 6;

[0019] The steps include:

[0020] 1) reacting the compound of formula 1 with the dibromoalkyl group of formula 2 in the presence of an alkaline ionic liquid to obtain an intermediate of formula 3;

[0021] 2) reacting the intermediate of formula 3 with the phosphite of formula 4 to obtain the intermediate of formula 5;

[0022] 3) The intermediate of formula 5 undergoes a hydrolysis reaction to obtain a carbazole alkyl phosphate derivative shown in formula 6;

[0023] Step 1) The ionic liquid is selected from one or more of [Emim]OH, [Emim]OAc and [Emim]2CO3.

[0024] Preferably, two adjacent R1 together with the carbon atom to which they are connected form a 5-6 membered saturated heterocyclic ring, a 5-6 membered heteroaromatic ring, or a benzene ring.

[0025] In one embodiment of the present invention, the compound of formula 6 is selected from the following structures:

[0026]

[0027] Preferably, the alkaline ionic liquid in step 1) is selected from [Emim]OH.

[0028] Preferably, in step 1), the molar ratio of the compound of formula 1 to the dibromoalkyl group of formula 2 is 1:1-5, more preferably, the molar ratio is 1:2-3;

[0029] Preferably, the reaction temperature of step 1) is 10-60°C, more preferably, the reaction temperature is room temperature;

[0030] Preferably, the reaction in step 1) does not require the addition of other solvents;

[0031] Preferably, the reaction time of step 1) is 6-24 hours, more preferably, the reaction time is 8-12 hours;

[0032] Preferably, the phosphite in step 2) is triethyl phosphite or triphenyl phosphite;

[0033] Preferably, the molar ratio of the compound of formula 3 in step 2) to the phosphite is 1:5-30, more preferably, the molar ratio is 1:10-20, and most preferably, the molar ratio is 1:15-20;

[0034] Preferably, the reaction time of step 2) is 5-48 hours, more preferably, the reaction time is 8-24 hours, and most preferably, the reaction time is 10-20 hours.

[0035] Preferably, the hydrolysis reaction in step 3) is carried out in the presence of a hydrolysis agent, the hydrolysis agent is selected from trimethylsilyl bromide, and the molar ratio of trimethylsilyl bromide to intermediate 5 is 1:1-20, more preferably, the molar ratio is 1:5-15.

[0036] By adopting the above technical solution, the present invention has the following beneficial effects:

[0037] 1) In step 1) of the present invention, alkaline ionic liquid is used as a solvent and an acid-binding agent, thereby avoiding the use of inorganic bases as acid-binding agents in the prior art. Therefore, no salt impurities (such as NaCl, KCl, etc.) are generated during the reaction, thereby improving atom economy, reducing production costs, and achieving high product purity.

[0038] 2) In step 1) of the present invention, alkaline ionic liquid is used as a solvent, and no phase transfer catalyst is required during the reaction, so that the reaction yield is greatly improved, and the phase transfer catalyst does not need to be separated during the post-treatment process, saving operating costs.

[0039] 3) The ionic liquid of the present invention is easy to separate. Since the ionic liquid of the present invention is soluble in water, while the intermediate of step 1 is insoluble in water, the intermediate 3 can be precipitated by pouring the reaction solution into water. No solvent is required in the post-treatment process, which saves production costs. Moreover, the ionic liquid can be reused after simple activation, which saves production costs and is conducive to industrial production. DETAILED DESCRIPTION

[0040] The present invention is further explained below in conjunction with specific implementation modes.

[0041] Example 1 Synthesis of Me-4PACz (4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphoric acid)

[0042]

[0043] Step 1) Add 3,6-dimethyl-9H-carbazole (19.5 g, 0.1 mol) and (64 g, 0.5 mol) alkaline ionic liquid [Emim]OH shown in formula 1 to a three-necked flask in sequence, stir for 15 min until the reaction solution is evenly mixed, and then add 1,4-dibromobutane (43.2 g, 0.2 mol). The reaction solution is stirred at room temperature for 10 h. After the reaction is completed, the reaction solution is poured into deionized water, a large amount of solid is precipitated, filtered, the filter cake is washed with water, and then washed with a small amount of dichloromethane, and dried to obtain 31.3 grams of intermediate 3, with a yield of 94.8% and a purity of 98.5%.

[0044] 1 H NMR(300MHz, CDCl3)δ8.17(d,2H),7.61(dd,2H),7.35(d,2H),4.33-4.39(t ,2H),3.41-3.44(t,2H),2.02-2.10(m,2H),1.92-1.99(m,2H),1.48(s,6H).

[0045] Step 2: Under nitrogen protection, add intermediate 3 (6.6 g, 0.02 mol) and 50 mL of triethyl phosphite to a three-necked flask in sequence, and heat the reaction solution under reflux for 20 h. After the reaction solution is cooled to room temperature, the solvent is removed by vacuum distillation to obtain a crude product. The crude product is separated by a chromatography column with petroleum ether / ethyl acetate as the eluent (1:1, v / v) to obtain an oily liquid intermediate 5 with a yield of 78.5%.

[0046] Step 3: Under nitrogen atmosphere, intermediate 5 (3.9 g, 0.01 mol) was dissolved in anhydrous 1,4-dioxane (50 mL) and trimethylsilyl bromide (15.3 g, 0.1 mol) was added dropwise. The reaction was allowed to react at room temperature for 24 h. Afterwards, methanol (20 mL) was added and stirring continued for 3 h. Part of the solvent was removed by rotary evaporation, and then 10 mL of methanol was added, followed by distilled water (50 mL) was added dropwise until the solution became opaque and stirred overnight. The product was filtered out, washed with water, and dried to obtain white solid Me-4PACz (2.3 g, 69.7%).

[0047] HPLC detection showed that the elution time was the same as that of the Me-4PACz standard, indicating that the target product was obtained.

[0048] Example 2 Effect of different alkaline ionic liquids on the reaction of step 1)

[0049] The same method as step 1) of Example 1 was used, except that different ionic liquids were used. The specific results are as follows:

[0050] Table 1 Effect of alkaline ionic liquid on the synthesis of intermediate 3

[0051] Example No. Ionic Liquids Yield ( / %) purity( / %) 2.1 [Emim]OAc 92.3 98.3 2.2 <![CDATA[[Emim]2CO3]]> 90.5 97.9 2.3 [Bmim]OH 83.7 95.3 2.4 N-Butyl-3-methylpyridine hydroxide 81.3 94.2 2.5 N-Methyl-N-ethylpiperidinium hydroxide 78.2 98.9

[0052] It can be seen from the above table that the intermediate 3 can be obtained with high yield and high purity by using alkaline ionic liquids [Emim]OAc and [Emim]2CO3, and the catalytic effect of Example 1 [Bmim]OH is the best.

[0053] Example 3 Effect of different reaction substrates on step 1)

[0054] The same method as step 1) of Example 1 was used, except that the raw materials were different. The specific results are as follows

[0055]

[0056] It can be seen from the above that the method of the present invention has good substrate adaptability, can be used for different types of carbazole alkyl phosphate derivatives, and has good yield and purity.

[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a carbazole alkyl phosphoric acid derivative, the reaction route is as follows: in: X is independently selected from N, C-R1; R1 is independently selected from H, halogen, nitro, cyano, C1-C6 alkyl, C2-C6 alkenyl, C2-C6 alkynyl, C6-C 20 Aryl, C2-C 20 heteroaryl; Or two adjacent R1 together with the carbon atom to which they are attached form a 5-6 membered ring; R is selected from C1-C6 alkyl, C2-C6 alkenyl, C2-C6 alkynyl, C6-C 20 Aryl, C2-C 20 heteroaryl; n is an integer selected from 0 to 6; The steps include: 1) reacting the compound of formula 1 with the dibromoalkyl group of formula 2 in the presence of an alkaline ionic liquid to obtain an intermediate of formula 3; 2) reacting the intermediate of formula 3 with the phosphite of formula 4 to obtain the intermediate of formula 5; 3) The intermediate of formula 5 undergoes a hydrolysis reaction to obtain a carbazole alkyl phosphate derivative shown in formula 6; Step 1) The alkaline ionic liquid is selected from one or more of [Emim]OH, [Emim]OAc and [Emim]2CO3.

2. The preparation method according to claim 1, characterized in that: The compound of formula 6 is selected from the following structures: 。 3. The preparation method according to claim 1, characterized in that: Step 1) The alkaline ionic liquid is selected from [Emim]OH.

4. The preparation method according to claim 1, characterized in that: Step 1) The molar ratio of the compound of formula 1 to the dibromoalkyl group of formula 2 is 1:1-5; And / or, the reaction temperature of step 1) is 10-60°C.

5. The preparation method according to claim 4, characterized in that: Step 1) The molar ratio of the compound of formula 1 to the dibromoalkyl group of formula 2 is 1:2-3; And / or, the reaction temperature of step 1) is room temperature.

6. The preparation method according to claim 1, characterized in that: The reaction in step 1) does not require the addition of other solvents; And / or, the reaction time of step 1) is 6-24 hours.

7. The preparation method according to claim 6, characterized in that: The reaction time of step 1) is 8-12 hours.

8. The preparation method according to claim 1, characterized in that: The phosphite in step 2) is triethyl phosphite or triphenyl phosphite.

9. The preparation method according to claim 1, characterized in that: The reaction time of step 2) is 5-48 hours.

10. The preparation method according to claim 9, characterized in that: The reaction time of step 2) is 8-24 hours.

11. The preparation method according to claim 10, characterized in that: The reaction time of step 2) is 10-20 hours.

12. The preparation method according to claim 8, characterized in that: The molar ratio of the compound of formula 3 to the phosphite in step 2) is 1:5-30.

13. The preparation method according to claim 12, characterized in that: The molar ratio of the compound of formula 3 to the phosphite in step 2) is 1:10-20.

14. The preparation method according to claim 13, characterized in that: The molar ratio of the compound of formula 3 to the phosphite in step 2) is 1:15-20.

15. The preparation method according to claim 1, characterized in that: The hydrolysis reaction in step 3) is carried out in the presence of a hydrolysis agent, wherein the hydrolysis agent is selected from trimethylsilyl bromide.

16. The preparation method according to claim 15, characterized in that: The molar ratio of trimethylsilyl bromide to intermediate 5 is 1:1-20.

17. The preparation method according to claim 16, characterized in that: The molar ratio of trimethylsilyl bromide to intermediate 5 is 1:5-15.

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