Preparation method of 5, 6-dibromoacenaphthene-1, 2-diketone

Abstract

The invention discloses a preparation method of 5, 6-dibromoacenaphthene-1, 2-diketone, and belongs to the technical field of organic synthesis. The method comprises the following steps: by taking 5, 6-dibromo-1, 2-acenaphthene as a raw material, generating 5, 6-dibromoacenaphthene under the action of a dehydrogenation reagent and a catalyst; then generating an epoxy intermediate under the action of an oxidizing agent; and finally, under the action of (1, 10-phenanthroline) tri (trifluoromethyl) copper (III), a catalyst and organic alkali, synthesizing the 5, 6-dibromoacenaphthene-1, 2-diketone. The yield of the 5, 6-dibromoacenaphthene-1, 2-diketone prepared by the method disclosed by the invention is 65-77%, and the product purity is gt; the content is 99.0%.

Description

Technical Field

[0001] The invention relates to a preparation method of 5,6-dibromoacenaphthene-1,2-dione, and belongs to the technical field of organic synthesis. Background Art

[0002] 5,6-Dibromoacenaphthene-1,2-dione (CAS No: 43017-99-8) is a widely used chemical raw material. As an intermediate for synthetic materials, it serves as an important reagent in organic synthesis, particularly providing the key acenaphthene chemical building block in the synthesis of complex organic molecules. Acenaphthene-based compounds (such as acenaphthene-1,2-dione) are also used to prepare olefin polymerization catalysts and participate in the synthesis of polymer materials. Furthermore, acenaphthene-based compounds and their derivatives have potential applications in the pharmaceutical field, and can be used in the synthesis and modification of active molecules such as antibacterial, anti-inflammatory, and anti-tumor agents.

[0003] The synthesis process of 5,6-dibromoacenaphthene-1,2-dione reported at home and abroad mainly includes: using acenaphthene as the raw material, brominating it with N-bromosuccinimide (NBS), and then oxidizing it with a chromium oxidant (CN111574538A; CN108409720A; CN108440424A; Eur J Inorg Chem, 2001, 5, 1183; J Am Chem Soc, 2000, 122, 4108; Chin Chem Lett, 2014, 25, 1399; Dyes and Pigments, 2011, 90, 297).

[0004] The currently reported routes are relatively simple. It is necessary to conduct in-depth research on the synthesis route of 5,6-dibromoacenaphthene-1,2-dione to provide a better, easier-to-obtain, safe, stable and economical process route to meet future market demand. Summary of the Invention

[0005] To overcome the above technical deficiencies, the present invention provides a method for preparing 5,6-dibromoacenaphthene-1,2-dione. Using 5,6-dibromo-1,2-dihydroacenaphthene as the raw material, 5,6-dibromoacenaphthene is reacted with a dehydrogenation agent and a catalyst to generate 5,6-dibromoacenaphthene; an oxidizing agent is then used to generate an epoxy intermediate; and finally, 5,6-dibromoacenaphthene-1,2-dione is synthesized with (1,10-phenanthroline)tris(trifluoromethyl)copper(III), a catalyst, and a base. The product purity is >99.0%.

[0006] The preparation method of 5,6-dibromoacenaphthene-1,2-dione of the present invention comprises the following steps:

[0007]

[0008] A. Mix 5,6-dibromo-1,2-dihydroacenaphthene and a dehydrogenation agent in an organic solvent and react under reflux to generate 5,6-dibromoacenaphthene;

[0009] B. Mixing 5,6-dibromoacenaphthylene, an oxidizing agent, and sodium bicarbonate in a chlorinated solvent and reacting them at room temperature to generate an epoxy intermediate;

[0010] C. The epoxy intermediate, (1,10-phenanthroline) tris(trifluoromethyl)copper(III), a catalyst and an organic base are mixed in an organic solvent and reacted under elevated temperature to generate 5,6-dibromoacenaphthene-1,2-dione.

[0011] Furthermore, in the above technical solution, in step A, the dehydrogenation reagent is selected from DDQ (2,3-dichloro-5,6-dicyanobenzoquinone), DEAD (diethyl azodicarboxylate) or DIAD (diisopropyl azodicarboxylate).

[0012] Furthermore, in the above technical solution, in step A, adding a catalyst tetrabutylammonium fluoride trihydrate can improve the reaction yield.

[0013] Furthermore, in the above technical solution, in step A, the organic solvent is selected from toluene, chlorobenzene or xylene.

[0014] Furthermore, in the above technical solution, in step A, the molar ratio of the 5,6-dibromo-1,2-dihydroacenaphthene, the dehydrogenation reagent and the catalyst is 1:2-2.1:0.01-0.05.

[0015] Furthermore, in the above technical solution, in step B, the oxidant is m-CPBA or tetraphenylporphyrin cobalt; and the chlorinated solvent is selected from dichloromethane, 1,2-dichloroethane or chloroform.

[0016] Furthermore, in the above technical solution, in step B, the molar ratio of the 5,6-dibromoacenaphthylene, the oxidant and the sodium bicarbonate is 1:1-1.5:2-3.

[0017] Furthermore, in the above technical solution, in step C, the catalyst is iodine; and the organic base is triethylamine, diisopropylethylamine or DBU.

[0018] Furthermore, in the above technical solution, in step C, the organic solvent is DMSO or sulfolane.

[0019] Furthermore, in the above technical solution, in step C, the molar ratio of the epoxy intermediate, (1,10-phenanthroline)tris(trifluoromethyl)copper(III), catalyst and organic base is 1:1-1.1:0.03-0.06:1.5-2.5.

[0020] Furthermore, in the above technical solution, in step C, the temperature of the temperature-raising reaction is selected from 60-120°C.

[0021] The present invention has the following beneficial effects:

[0022] A. The present invention uses cheap and easily available 5,6-dibromo-1,2-dihydroacenaphthene as a raw material and prepares 5,6-dibromoacenaphthene-1,2-dione through a three-step reaction. The design is reasonable and has certain cost advantages.

[0023] B. The present invention does not adopt the traditional direct oxidation method of 5,6-dibromo-1,2-dihydroacenaphthene, but first adopts a dehydrogenation olefination reaction, then an epoxidation reaction, and finally oxidation to a diketone, which has a high overall yield and is easy to operate.

[0024] C. In the first step of dehydrogenation aromatization of the present invention, when DDQ is used, the system has relatively more impurities. After optimization, when DIAD / DEAD / n-Bu4NF is used, the yield can be increased to more than 90%; in the third step of oxidation, the best combination is Cu(phen)(CF3)3 / DBU / cyclopentane reaction system. Specific embodiments

[0025] The present invention will be further described below by way of specific examples. These embodiments should be understood to be merely illustrative of the present invention and not intended to limit the scope of protection of the present invention. After reading the contents described herein, those skilled in the art may make various changes or modifications to the present invention, and these equivalent variations and modifications also fall within the scope defined by the claims of the present invention.

[0026] Example 1

[0027] Under nitrogen protection, 5,6-dibromo-1,2-dihydroacenaphthene (31.2 g, 0.1 mol), DIAD (40.4 g, 0.2 mol), tetrabutylammonium fluoride trihydrate (0.95 g, 0.003 mol) and 500 mL of toluene were added to the reaction flask, the temperature was raised to reflux conditions, the reaction was carried out for 9 hours, the temperature was lowered to room temperature, the silica gel column was filtered, 100 mL of water was added and washed twice, the organic layer was concentrated, the crude product was slurried with n-hexane, filtered, and dried to obtain 29.1 g of 5,6-dibromoacenaphthene, the yield was 94%, and the HPLC result was 99.1%. 1 HNMR (400 MHz, CDCl3): 7.87 (d, 2H), 7.4 (d, 2H), 6.86 (s, 2H). Without the addition of tetrabutylammonium fluoride trihydrate, 22.6 g of 5,6-dibromoacenaphthylene was obtained with a yield of 73%, and an HPLC analysis of 99.4%.

[0028] Example 2

[0029] Under nitrogen, a reaction flask was charged with 5,6-dibromo-1,2-dihydroacenaphthene (31.2 g, 0.1 mol), DDQ (45.4 g, 0.2 mol), tetrabutylammonium fluoride trihydrate (0.95 g, 0.003 mol), and 500 mL of toluene. The mixture was heated to reflux and reacted for 14 hours. The mixture was cooled to room temperature and filtered through a silica gel column. The mixture was washed twice with 100 mL of water. The organic layer was concentrated, and the crude product was slurried with n-hexane, filtered, and dried to obtain 25.1 g of 5,6-dibromoacenaphthene with an 81% yield and an HPLC purity of 98.9%. Without the addition of tetrabutylammonium fluoride trihydrate, 21.9 g of 5,6-dibromoacenaphthene was obtained with a 71% yield and an HPLC purity of 98.0%.

[0030] Example 3

[0031] Under nitrogen protection, 5,6-dibromoacenaphthylene (15.5 g, 0.05 mol), sodium bicarbonate (8.4 g, 0.1 mol) and 100 mL of dichloromethane were added to the reaction flask. Under stirring, a solution of 85% m-CPBA (12.2 g, 0.06 mol) dissolved in 120 mL of dichloromethane was slowly added dropwise. The reaction was carried out at room temperature for 8 hours, and then the temperature was lowered to 0 ° C. 100 mL of Na2S2O3 (5%) was slowly added, the temperature was raised to room temperature, the layers were separated, and the organic layer was washed with 50 mL of saturated sodium bicarbonate aqueous solution. The organic layer was concentrated and the crude product was purified by column chromatography with an eluent of n-hexane / ethyl acetate (v / v = 20 / 1) to give 14.8 g of the epoxy intermediate with a yield of 91% and an HPLC content of 99.4%. 1 HNMR(400MHz, CDCl3):7.77(d,2H),7.18(d,2H),4.75(s,2H).

[0032] Example 4

[0033] Under nitrogen, the epoxy intermediate (16.3 g, 0.05 mol), (1,10-phenanthroline) tris(trifluoromethyl)copper(III) (7.9 g, 0.0525 mol), iodine (0.5 g, 0.002 mol), DBU (15.2 g, 0.1 mol), and 400 mL of sulfolane were added to a reaction flask. The temperature was raised to 100°C and the reaction was allowed to proceed for 9 hours. The reaction was detected by TLC, and the temperature was lowered to room temperature. 200 mL of dichloromethane was added, the reaction mixture was filtered, and then washed twice with 1 M aqueous hydrochloric acid and water. The organic layer was concentrated, and the crude product was recrystallized from chlorobenzene to obtain 15.3 g of the product 5,6-dibromoacenaphthene-1,2-dione, with a yield of 90% and an HPLC content of 99.2%. 1 HNMR(400MHz, CDCl3):8.27(d,2H),7.92(d,2H).

[0034] Example 5

[0035] Under nitrogen, the epoxy intermediate (16.3 g, 0.05 mol), (1,10-phenanthroline) tris(trifluoromethyl)copper(III) (7.9 g, 0.0525 mol), triethylamine (10.1 g, 0.1 mol), and 400 mL of DMSO were added to the reaction flask. The temperature was raised to 120°C and the reaction was allowed to proceed for 12 hours. The reaction was completed by TLC, and the temperature was lowered to room temperature. 200 mL of dichloromethane was added, the mixture was filtered, and then washed twice with 1 M aqueous hydrochloric acid and water. The organic layer was concentrated, and the crude product was recrystallized from chlorobenzene to obtain 13.8 g of the product, 5,6-dibromoacenaphthene-1,2-dione, with a yield of 81% and an HPLC purity of 98.7%.

[0036] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes based on the technical solutions and inventive concepts of the present invention within the technical scope disclosed in the present invention, and they should be covered by the scope of protection of the present invention.

Claims

1. A method for preparing 5,6-dibromoacenaphthene-1,2-dione, characterized in that: The steps include: A. Mix 5,6-dibromo-1,2-dihydroacenaphthene and a dehydrogenation agent in an organic solvent and react under reflux to generate 5,6-dibromoacenaphthene; B. Mixing 5,6-dibromoacenaphthylene, an oxidizing agent, and sodium bicarbonate in a chlorinated solvent and reacting them at room temperature to generate an epoxy intermediate; C. The epoxy intermediate, (1,10-phenanthroline) tris(trifluoromethyl)copper(III), a catalyst and an organic base are mixed in an organic solvent and reacted under elevated temperature to generate the product 5,6-dibromoacenaphthene-1,2-dione.

2. The method for preparing 5,6-dibromoacenaphthene-1,2-dione according to claim 1, characterized in that: In step A, the dehydrogenation reagent is selected from DDQ, DEAD or DIAD.

3. The method for preparing 5,6-dibromoacenaphthene-1,2-dione according to claim 1, characterized in that: In step A, the reaction is carried out in the presence of tetrabutylammonium fluoride trihydrate as a catalyst.

4. The method for preparing 5,6-dibromoacenaphthene-1,2-dione according to claim 1, characterized in that: In step A, the organic solvent is selected from toluene, chlorobenzene or xylene.

5. The method for preparing 5,6-dibromoacenaphthene-1,2-dione according to claim 3, characterized in that: In step A, the molar ratio of the 5,6-dibromo-1,2-dihydroacenaphthene, the dehydrogenation reagent and the catalyst is 1:2-2.1:0.01-0.

05.

6. The method for preparing 5,6-dibromoacenaphthene-1,2-dione according to claim 1, characterized in that: In step B, the oxidant is m-CPBA or tetraphenylporphyrin cobalt; and the chlorinated solvent is selected from dichloromethane, 1,2-dichloroethane or chloroform.

7. The method for preparing 5,6-dibromoacenaphthene-1,2-dione according to claim 1, characterized in that: In step B, the molar ratio of 5,6-dibromoacenaphthylene, oxidant and sodium bicarbonate is 1:1-1.5:2-3.

8. The method for preparing 5,6-dibromoacenaphthene-1,2-dione according to claim 1, characterized in that: In step C, the catalyst is iodine; the organic base is selected from triethylamine, diisopropylethylamine or DBU; and the organic solvent is selected from DMSO or sulfolane.

9. The method for preparing 5,6-dibromoacenaphthene-1,2-dione according to claim 1, characterized in that: In step C, the molar ratio of the epoxy intermediate, (1,10-phenanthroline) tris(trifluoromethyl)copper(III), catalyst and organic base is 1:1-1.1:0.03-0.06:1.5-2.

5.

10. The method for preparing 5,6-dibromoacenaphthene-1,2-dione according to claim 1, characterized in that: The reaction temperature is selected from 60-120°C.

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