A process for the preparation of 1-(tert-butyl)-3-chloronaphthalene

Abstract

The application discloses a preparation method of 1-(tert-butyl)-3-chloronaphthalene and belongs to the field of organic chemical synthesis. The preparation method uses 1-tert-butyl naphthalene and N-chlorosuccinimide as raw materials, and 1-(tert-butyl)-3-chloronaphthalene is prepared under the action of a catalyst and a ligand. The reaction is carried out in a solvent, and the catalyst is a palladium salt. The method uses cheap and readily available 1-tert-butyl naphthalene and N-chlorosuccinimide as raw materials, and the product 1-(tert-butyl)-3-chloronaphthalene is obtained through one-step C-H meta-activation reaction. Compared with the prior art, the method has the advantages of short reaction steps, readily available raw materials, mild reaction conditions, simple post-treatment and purification, high yield, low production cost, good product quality and the like, and is favorable for large-scale industrial production.

Description

Technical Field

[0001] This invention belongs to the field of organic chemical synthesis, and specifically relates to a method for preparing 1-(tert-butyl)-3-chloronaphthalene. Background Technology

[0002] 1-(tert-butyl)-3-chloronaphthalene is an important chemical intermediate that can be used to further synthesize organic optoelectronic materials. These materials are already widely used in organic / polymer light-emitting diodes (OLEDs / PLEDs), photodetectors, organic solar cells (OSCs), nonlinear optical devices, and organic field-effect transistors (OFETs). Therefore, research on the synthesis of 1-(tert-butyl)-3-chloronaphthalene is of great significance.

[0003] Literature reports that the synthesis of 1-(tert-butyl)-3-chloronaphthalene mainly follows two routes.

[0004] Route 1: Patent US2022216410 reports a method for synthesizing 1-(tert-butyl)-3-chloronaphthalene: using 6-tert-butyl-4-hydroxy-pyran-2-one as a raw material, 1-(tert-butyl)-3-chloronaphthalene is synthesized in two steps via chlorination and cyclization reactions, with a yield of approximately 58%.

[0005]

[0006] Route 2: Patent CN114736099 uses 1-naphthylamine as raw material and synthesizes 1-(tert-butyl)-3-chloronaphthalene through four steps of chlorination, bromination, diazotization reduction and coupling reaction, with a reaction yield of about 36%.

[0007]

[0008] Of the two synthetic routes mentioned above, Route 1 has a shorter reaction step and higher yield, but the raw material 6-tert-butyl-4-hydroxy-pyran-2-one is not readily available and is expensive, making it unsuitable for industrial production. Route 2 uses 1-naphthylamine as a raw material, which is inexpensive and readily available, but the reaction step is longer, the yield is lower, and there are many side reactions during the reaction. The reaction purification requires column purification, and the separation and purification process is not suitable for industrial-scale production.

[0009] Technicians have been continuously researching methods for synthesizing 1-(tert-butyl)-3-chloronaphthalene in order to obtain a more economical, green, and efficient new route for the synthesis of 1-(tert-butyl)-3-chloronaphthalene.

[0010] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0011] The purpose of this invention is to solve the problems of expensive raw materials, long reaction steps, and low yield in existing methods for synthesizing 1-(tert-butyl)-3-chloronaphthalene, and to provide an economical, green, and efficient method for preparing 1-(tert-butyl)-3-chloronaphthalene.

[0012] The first aspect of this invention provides a method for preparing 1-(tert-butyl)-3-chloronaphthalene, using 1-tert-butylnaphthalene and N-chlorosuccinimide as raw materials, and preparing 1-(tert-butyl)-3-chloronaphthalene under the action of a catalyst and a ligand, as shown in the following reaction formula:

[0013]

[0014] The reaction is carried out in a solvent, the catalyst is a palladium salt, and the ligand has the following structure:

[0015]

[0016] In one embodiment of the present invention, the palladium salt is selected from one or more palladium salts such as palladium chloride, palladium acetate, tetra(triphenylphosphine)palladium, palladium trifluoroacetate, palladium acetylacetonate, and tris(dibenzylideneacetone)dipalladium.

[0017] In one embodiment of the present invention, the molar ratio of N-chlorosuccinimide to 1-tert-butylnaphthalene is 1:1 to 3:1.

[0018] In one embodiment of the present invention, the molar ratio of the catalyst to 1-tert-butylnaphthalene is 0.001:1 to 0.01:1.

[0019] In one embodiment of the present invention, the molar ratio of the ligand to 1-tert-butylnaphthalene is 0.002:1 to 0.02:1.

[0020] In one embodiment of the present invention, the above preparation method specifically includes the following steps:

[0021] a. Add the above solvent, 1-tert-butylnaphthalene, N-chlorosuccinimide, the above catalyst, and the above ligand into the reaction vessel;

[0022] b. The reaction is carried out under an inert gas atmosphere to obtain 1-(tert-butyl)-3-chloronaphthalene.

[0023] In one embodiment of the present invention, the solvent is selected from one or more of dichloroethane, chloroform, tetrahydrofuran, dioxane, o-dichlorobenzene, and chlorobenzene.

[0024] In one embodiment of the present invention, the mass ratio of the solvent to 1-tert-butylnaphthalene is 3:1 to 10:1.

[0025] In one embodiment of the present invention, the inert gas is selected from one or more of nitrogen, argon, helium, and neon.

[0026] In one embodiment of the present invention, the above reaction is carried out under conditions of heating and / or stirring.

[0027] In one embodiment of the present invention, the reaction time is 6-12 hours.

[0028] In one embodiment of the present invention, the temperature for the above-mentioned heating is 60°C-110°C.

[0029] In one embodiment of the present invention, the above preparation method further includes the steps of solvent recovery, extraction, organic layer desolventizing, and crystallization.

[0030] In one embodiment of the present invention, the solvent system used for the extraction consists of water and an extraction solvent, wherein the extraction solvent is selected from at least one of xylene, toluene, dichlorobenzene, chlorobenzene, and ethyl acetate.

[0031] In one embodiment of the present invention, the solvent used for the crystallization is selected from at least one of ethanol, methanol, isopropanol, toluene, xylene, and ethyl acetate.

[0032] Compared with the prior art, the technical effects achieved by the present invention are as follows:

[0033] (1) The preparation method of the present invention uses inexpensive and readily available 1-tert-butylnaphthalene and N-chlorosuccinimide as raw materials, and obtains the product 1-(tert-butyl)-3-chloronaphthalene through a one-step CH meta-activation reaction. Compared with the prior art, the reaction steps are short, the raw materials are readily available, and the production cost is low and the environment is friendly.

[0034] (2) The preparation method of the present invention can react at a relatively low temperature (60℃~110℃), with mild conditions, simple post-processing purification, high product purity, high yield, low production cost and good product quality, which is conducive to large-scale industrial production and has significant economic benefits.

[0035] (3) In this invention, the catalyst and ligand are crucial to the reaction. Without a catalyst or with a non-palladium salt catalyst, the chlorination reaction mainly occurs at the para-tert-butyl position, failing to selectively generate the target product 1-(tert-butyl)-3-chloronaphthalene. The ligand used is a specific type of ligand specially selected for the reaction system. By changing the substituents on the benzene ring of the ligand, the ligand's electron-donating ability and steric hindrance are enhanced. When a methyl or cyclohexyl group is introduced into the benzene ring of the ligand, due to the ligand's strong electron-donating ability and large steric hindrance, it coordinates with the palladium salt, activating the meta-tert-butyl position, thus causing the chlorination reaction to occur at the meta-tert-butyl position. Without a ligand or with a conventional type of ligand (such as 1,10-phenanthroline), the reaction is essentially impossible. Detailed Implementation

[0036] Unless otherwise expressly stated, throughout the specification and claims, the term "comprising" or its variations such as "including" or "comprises" shall be understood to include the stated elements or components without excluding other elements or other components.

[0037] The technical solution of the present invention is illustrated below through specific embodiments. It should be understood that the one or more steps mentioned in the present invention do not preclude the existence of other methods and steps before or after the combined steps, or that other methods and steps may be inserted between these explicitly mentioned steps. It should also be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Unless otherwise stated, the numbering of each method step is only for the purpose of identifying each method step, and not for limiting the order of each method or limiting the scope of the present invention. Changes or adjustments to their relative relationships, without substantial changes to the technical content, can also be considered as within the scope of the present invention.

[0038] The raw materials and instruments used in the examples are not subject to any specific restrictions on their source; they can be purchased from the market or prepared according to conventional methods known to those skilled in the art.

[0039] Example 1

[0040] Under nitrogen protection, 279 g of dichloroethane (99%), 55.8 g of 1-tert-butylnaphthalene (99%, 0.3 mol), 80.9 g of N-chlorosuccinimide (99%, 0.6 mol), 0.25 g of palladium acetate (99%, 0.0015 mol), and 1.1 g of ligand L (99%, 0.003 mol) were added to a 1000 mL reaction flask. After the addition was complete, the temperature was raised to 80 °C, the stirring speed was 600 rpm, and the reaction was maintained at this temperature for 8 hours. After the reaction was completed, the solvent was recovered, and water and xylene were added to the residue for extraction. The organic layer was desolventized to obtain a crude product, which was then crystallized from ethanol to obtain 57.0 g of 1-(tert-butyl)-3-chloronaphthalene with a purity of 99.9% and a yield of 86.8%.

[0041] Example 2

[0042] Under argon protection, 558 g of o-dichlorobenzene (99%), 55.8 g of 1-tert-butylnaphthalene (99%, 0.3 mol), 121.4 g of N-chlorosuccinimide (99%, 0.9 mol), 0.54 g of palladium chloride (99%, 0.003 mol), and 2.3 g of ligand L (99%, 0.006 mol) were added to a 1000 mL reaction flask. After the addition was complete, the temperature was raised to 110 °C, the stirring speed was 600 rpm, and the reaction was maintained at this temperature for 6 hours. After the reaction was completed, the solvent was recovered, and water and xylene were added to the residue for extraction. The organic layer was desolventized to obtain a crude product, which was then crystallized from ethanol to obtain 61.4 g of 1-(tert-butyl)-3-chloronaphthalene with a purity of 99.9% and a yield of 92.6%.

[0043] Example 3

[0044] Under helium protection, 279 g of tetrahydrofuran (99%), 55.8 g of 1-tert-butylnaphthalene (99%, 0.3 mol), 80.9 g of N-chlorosuccinimide (99%, 0.6 mol), 0.25 g of palladium acetate (99%, 0.0015 mol), and 1.1 g of ligand L (99%, 0.003 mol) were added to a 1000 mL reaction flask. After the addition was complete, the temperature was raised to 60 °C, the stirring speed was 600 rpm, and the reaction was maintained at this temperature for 12 hours. After the reaction was completed, the solvent was recovered, and water and toluene were added to the residue for extraction. The organic layer was desolventized to obtain a crude product, which was then crystallized from methanol to obtain 54.1 g of 1-(tert-butyl)-3-chloronaphthalene with a purity of 99.9% and a yield of 82.3%.

[0045] Example 4

[0046] Under nitrogen protection, 167.4 g of dichloroethane (99%), 55.8 g of 1-tert-butylnaphthalene (99%, 0.3 mol), 40.5 g of N-chlorosuccinimide (99%, 0.3 mol), 1.73 g of tetrakis(triphenylphosphine)palladium (99%, 0.0015 mol), and 1.1 g of ligand L (99%, 0.003 mol) were added to a 1000 mL reaction flask. After the addition was complete, the temperature was raised to 80 °C, the stirring speed was 600 rpm, and the reaction was maintained at this temperature for 8 hours. After the reaction was completed, the solvent was recovered, and the residue was extracted with water and dichlorobenzene. The organic layer was desolventized to obtain a crude product, which was then crystallized from ethanol to give 7.4 g of 1-(tert-butyl)-3-chloronaphthalene with a purity of 98.9% and a yield of 11.3%.

[0047] Example 5

[0048] Under nitrogen protection, 279 g of dichloroethane (99%), 55.8 g of 1-tert-butylnaphthalene (99%, 0.3 mol), 40.5 g of N-chlorosuccinimide (99%, 0.3 mol), 0.068 g of palladium trifluoroacetate (99%, 0.0003 mol), and 1.1 g of ligand L (99%, 0.003 mol) were added to a 1000 mL reaction flask. After the addition was complete, the temperature was raised to 80 °C, the stirring speed was 600 rpm, and the reaction was maintained at this temperature for 8 hours. After the reaction was completed, the solvent was recovered, and water and xylene were added to the residue for extraction. The organic layer was desolventized to obtain a crude product, which was then crystallized from xylene to obtain 30.8 g of 1-(tert-butyl)-3-chloronaphthalene with a purity of 99.5% and a yield of 46.9%.

[0049] Example 6

[0050] Under nitrogen protection, 279 g of dichloroethane (99%), 55.8 g of 1-tert-butylnaphthalene (99%, 0.3 mol), 80.9 g of N-chlorosuccinimide (99%, 0.6 mol), 0.46 g of palladium acetylacetonate (99%, 0.0015 mol), and 0.22 g of ligand L (99%, 0.0006 mol) were added to a 1000 mL reaction flask. After the addition was complete, the temperature was raised to 80 °C, the stirring speed was 600 rpm, and the reaction was maintained at this temperature for 8 hours. After the reaction was completed, the solvent was recovered, and water and chlorobenzene were added to the residue for extraction. The organic layer was desolventized to obtain a crude product, which was crystallized from isopropanol to obtain 40.6 g of 1-(tert-butyl)-3-chloronaphthalene with a purity of 99.9% and a yield of 61.8%.

[0051] Example 7

[0052] Under nitrogen protection, 279 g of dichloroethane (99%), 55.8 g of 1-tert-butylnaphthalene (99%, 0.3 mol), 80.9 g of N-chlorosuccinimide (99%, 0.6 mol), 1.37 g of tris(dibenzylacetone)palladium (99%, 0.0015 mol), and 1.1 g of ligand L (99%, 0.003 mol) were added to a 1000 mL reaction flask. After the addition was complete, the temperature was raised to 80 °C, the stirring speed was 600 rpm, and the reaction was maintained at this temperature for 8 hours. After the reaction was completed, the solvent was recovered, and the residue was extracted with water and ethyl acetate. The organic layer was desolventized to obtain a crude product, which was crystallized from ethyl acetate to give 59.7 g of 1-(tert-butyl)-3-chloronaphthalene with a purity of 99.9% and a yield of 90.9%.

[0053] Comparative Example 1 (different from Example 1 in that it does not contain a catalyst)

[0054] Under nitrogen protection, 279 g of dichloroethane (99%), 55.8 g of 1-tert-butylnaphthalene (99%, 0.3 mol), 80.9 g of N-chlorosuccinimide (99%, 0.6 mol), and 1.1 g of ligand L (99%, 0.003 mol) were added to a 1000 mL reaction flask. After the addition was complete, the temperature was raised to 80 °C, the stirring speed was 600 rpm, and the reaction was maintained at this temperature for 8 hours. After the reaction was completed, the solvent was recovered, and the residue was extracted with water and xylene. The organic layer was sampled and analyzed by GC-MS. No product 1-(tert-butyl)-3-chloronaphthalene was detected.

[0055] Comparative Example 2 (different from Example 1 in that it uses a non-palladium salt catalyst)

[0056] Under nitrogen protection, 279 g of dichloroethane (99%), 55.8 g of 1-tert-butylnaphthalene (99%, 0.3 mol), 80.9 g of N-chlorosuccinimide (99%, 0.6 mol), 1.1 g of ligand L (99%, 0.003 mol), and 0.27 g of copper acetate (99%, 0.0015 mol) were added to a 1000 mL reaction flask. After the addition was complete, the temperature was raised to 80 °C, the stirring speed was 600 rpm, and the reaction was maintained at this temperature for 8 hours. After the reaction was completed, the solvent was recovered, and the residue was extracted with water and xylene. The organic layer was sampled and analyzed by GC-MS. No product 1-(tert-butyl)-3-chloronaphthalene was detected.

[0057] Comparative Examples 1 and 2 demonstrate that the catalyst is crucial for the reaction. Without the addition of a catalyst or the use of a non-palladium salt catalyst, the chlorination reaction mainly occurs at the para-tert-butyl position, and the target product 1-(tert-butyl)-3-chloronaphthalene cannot be selectively generated.

[0058] Comparative Example 3 (different from Example 1 in that it does not contain ligands)

[0059] Under nitrogen protection, 279 g of dichloroethane (99%), 55.8 g of 1-tert-butylnaphthalene (99%, 0.3 mol), 80.9 g of N-chlorosuccinimide (99%, 0.6 mol), and 0.25 g of palladium acetate (99%, 0.0015 mol) were added to a 1000 mL reaction flask. After the addition was complete, the temperature was raised to 80 °C, the stirring speed was 600 rpm, and the reaction was maintained at this temperature for 8 hours. After the reaction was completed, the solvent was recovered, and the residue was extracted with water and xylene. The organic layer was sampled and analyzed by GC-MS. No product 1-(tert-butyl)-3-chloronaphthalene was detected.

[0060] Comparative Example 4 (different from Example 1 in that it uses 1,10-phenanthroline as the ligand)

[0061] Under nitrogen protection, 279 g of dichloroethane (99%), 55.8 g of 1-tert-butylnaphthalene (99%, 0.3 mol), 80.9 g of N-chlorosuccinimide (99%, 0.6 mol), 0.25 g of palladium acetate (99%, 0.0015 mol), and 0.55 g of ligand 1,10-phenanthroline (99%, 0.003 mol) were added to a 1000 mL reaction flask. After the addition was complete, the temperature was raised to 80 °C, the stirring speed was 600 rpm, and the reaction was maintained at this temperature for 8 hours. After the reaction was completed, the solvent was recovered, and the residue was extracted with water and xylene. The organic layer was sampled and analyzed by GC-MS. No product 1-(tert-butyl)-3-chloronaphthalene was detected.

[0062] Comparative Examples 3 and 4 illustrate that the ligand is crucial to the reaction in this invention. The ligands used are specific types chosen for the reaction system. By altering the substituents on the benzene ring of the ligand, the ligand's electron-donating ability and steric hindrance are enhanced. When a methyl or cyclohexyl group is introduced into the benzene ring of the ligand, due to the ligand's strong electron-donating ability and large steric hindrance, it coordinates with the palladium salt, activating the tert-butyl meta position, allowing the chlorination reaction to occur at the tert-butyl meta position. Without the addition of a ligand, or with the addition of a conventional type of ligand (such as 1,10-phenanthroline in Comparative Example 4), the reaction is essentially impossible to proceed.

[0063] The foregoing description of specific exemplary embodiments of the invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A method for preparing 1-(tert-butyl)-3-chloronaphthalene, characterized in that, The preparation method uses 1-tert-butylnaphthalene and N-chlorosuccinimide as raw materials to prepare 1-(tert-butyl)-3-chloronaphthalene under the action of a catalyst and ligands, and the reaction formula is as follows: The reaction is carried out in a solvent, the catalyst is a palladium salt, and the ligand has the following structure:

2. The preparation method according to claim 1, characterized in that, The palladium salt is selected from one or more of palladium chloride, palladium acetate, tetra(triphenylphosphine)palladium, palladium trifluoroacetate, palladium acetylacetonate, and tris(dibenzylideneacetone)dipalladium.

3. The preparation method according to claim 1, characterized in that, The molar ratio of N-chlorosuccinimide to 1-tert-butylnaphthalene is 1:1-3:1; And / or, the molar ratio of the catalyst to 1-tert-butylnaphthalene is 0.001:1 to 0.01:1; And / or, the molar ratio of the ligand to 1-tert-butylnaphthalene is 0.002:1 to 0.02:

1.

4. The preparation method according to claim 1, characterized in that, The preparation method specifically includes the following steps: a. The solvent, 1-tert-butylnaphthalene, N-chlorosuccinimide, the catalyst, and the ligand are fed into a reaction vessel; b. The reaction is carried out under an inert gas atmosphere to obtain 1-(tert-butyl)-3-chloronaphthalene.

5. The preparation method according to claim 1, characterized in that, The solvent is selected from one or more of dichloroethane, chloroform, tetrahydrofuran, dioxane, o-dichlorobenzene, and chlorobenzene; And / or, the mass ratio of the solvent to 1-tert-butylnaphthalene is 3:1 to 10:

1.

6. The preparation method according to claim 4, characterized in that, The inert gas is selected from one or more of nitrogen, argon, helium, and neon.

7. The preparation method according to claim 4, characterized in that, The reaction is carried out under heating conditions; And / or, the reaction time is 6-12 h.

8. The preparation method according to claim 7, characterized in that, The temperature for the heating is 60℃-110℃.

9. The preparation method according to claim 4, characterized in that, The preparation method also includes steps of solvent recovery, extraction, organic layer desolventizing, and crystallization.

10. The preparation method according to claim 9, characterized in that, The solvent system used for extraction consists of water and an extraction solvent, wherein the extraction solvent is selected from at least one of xylene, toluene, dichlorobenzene, chlorobenzene, and ethyl acetate; And / or, the solvent used for the crystallization is selected from at least one of ethanol, methanol, isopropanol, toluene, xylene, and ethyl acetate.

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