A method for preparing an aromatic amine compound

Abstract

The application discloses a preparation method of an aromatic amine compound. The aromatic amine compound is obtained from an aromatic nitro compound in a triethylsilane and iodine element system at room temperature through one-step reaction. The application is easy to prepare under the premise of obtaining a good yield and is simple in overall step operation and mild in reaction process.

Description

Technical Field

[0001] This invention belongs to the field of organic compound preparation, specifically relating to a method for preparing aromatic amine compounds. Background Technology

[0002] Aromatic amines are important intermediates in the fine chemical, dye, and pigment industries. Amines are widely distributed in nature and possess a wide range of biological activities. The reduction of nitrobenzene to aniline is one of the most important reactions in aromatic chemistry. There are many methods for nitro reduction, including: reduction with a metal and hydrochloric acid (common metals include zinc and iron, suitable for compounds stable to acids); catalytic hydrogenation using catalysts such as Pt and Ni; and mild reduction that can reduce only the nitro group. There are also some characteristic reduction reactions of nitrobenzene, such as the reduction to phenylhydroxylamine with zinc under weakly acidic conditions; and reduction under alkaline conditions, yielding azobenzene in aqueous solution and hydrazine in alcoholic solution.

[0003] However, various reaction transition states exist in this type of nitro reduction method. The appearance of nitroso, azobenzene, and hydrazine is unavoidable. When tracking the reaction, many reaction points can usually be seen. Under normal circumstances, if the reaction time is appropriately extended, these intermediates will be basically completely reduced. However, the recovery of metal ions is relatively difficult. Some of these technologies have great limitations in terms of safety and operation.

[0004] Triethylsilane is an inexpensive, stable, and low-toxicity substance that is often used as a cleaning agent. On the other hand, due to its... Due to its compatibility with acids, transition metals (such as Pd, Pt, Mo, Ni, Au, Mn, Rh, Ru, Os, and Ir) and their complexes, triethylsilane is widely used as a reducing agent in chemical reactions. Its ability to protect (silanize) and derive various compounds (such as alcohols, phenols, thiols, amines, carbonyl groups, carboxylic acids, amides, alkenes, and enols) is beneficial in various fields, such as modern natural product synthesis and medicinal chemistry. Over the past four decades, triethylsilane has shown great promise as an alternative reducing agent for the hydrogenation of alkenes and CN / CO / SO groups, as well as for the regioselective hydrogenation of multifunctional scaffolds.

[0005] Maryam Mirza-Aghayana et al. (Palladium-catalyzed reduction of nitroaromatic compounds to the corresponding anilines) reported in 2010 the reduction of nitroaromatic compounds to the corresponding anilines using PdCl2-Et3SiH system under mild conditions. Different nitroaromatic compounds were directly reacted with Et3SiH in ethanol in the presence of 10 mol% PdCl2 at room temperature with high yield, but inert atmosphere and anhydrous solvent were required, and it was limited to nitroaromatic compounds.

[0006] CN 1660771A reported in 2004 that nitrobenzene was reduced at high temperature in the presence of alcohol solution and catalyst, wherein the catalyst was Pt / Al2O3, NiB, Renay-Ni. Although this invention reduces the reaction steps and simplifies the production process, the reaction temperature is high, which is easy to cause resource waste and is not conducive to green production. SUMMARY

[0007] The purpose of the present application is to overcome the shortcomings of the prior art and provide a preparation method of aromatic amine compounds.

[0008] The present application adopts the following technical scheme:

[0009] A preparation method of aromatic amine compounds, using aromatic nitro compounds as raw materials, in a triethylsilane and iodine elemental system, under room temperature conditions, one-step reaction to obtain aromatic amine compounds.

[0010] Further, the reduction reaction process is as follows: at room temperature, the aromatic nitro compound and the solvent are added to the reactor and stirred, and after dissolution, triethylsilane and iodine elemental are added to the reaction system; after addition, continue to stir, take sample GC tracking; after the reaction stops, column chromatography is used to separate the aromatic amine compounds.

[0011] Further, in the reduction reaction, the molar ratio of triethylsilane to aromatic nitro compound is 8.0:1.0.

[0012] Further, in the reduction reaction, the molar ratio of iodine elemental to aromatic nitro compound is 0.5:1.0.

[0013] Further, in the reduction reaction, the solvent is dichloroethane.

[0014] Further, in the reduction reaction, the volume of the solvent used to the mass of the aromatic nitro compound is in the range of 8.0-15.0 mL:1.0 g.

[0015] From the above description of the present application, compared with the prior art, the beneficial effects of the present application are: the present application uses aromatic nitro compounds as raw materials, and obtains aromatic amine compounds in a one-step reaction under the condition of triethylsilane and elemental iodine system at room temperature. On the premise of obtaining good yield, the overall step operation is simple, the reaction process is mild, and it is easy to prepare. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is a synthetic route map of the present application;

[0017] Figure 2 is a synthetic route map of Example 1;

[0018] Figure 3 is a synthetic route map of Example 2;

[0019] Figure 4 is a synthetic route map of Example 3;

[0020] Figure 5 is a synthetic route map of Example 4;

[0021] Figure 6 is a synthetic route map of Example 5;

[0022] Figure 7 is a synthetic route map of Example 6;

[0023] Figure 8 is a synthetic route map of Example 7;

[0024] Figure 9 is a synthetic route map of Example 8;

[0025] Figure 10 is a synthetic route map of Example 9;

[0026] Figure 11 is a synthetic route map of Example 10;

[0027] Figure 12 is a synthetic route map of Example 11;

[0028] Figure 13 is a synthetic route map of Example 12;

[0029] Figure 14 is a synthetic route map of Example 13;

[0030] Figure 15 is a synthetic route map of Example 14;

[0031] Figure 16 is a synthetic route map of Example 15;

[0032] Figure 17Synthetic route map for Example 16;

[0033] Figure 18 Synthetic route map for Example 17. DETAILED DESCRIPTION

[0034] The application is further described below by way of specific embodiments.

[0035] A preparation method of an aromatic amine compound, taking an aromatic nitro compound as raw material, obtaining the aromatic amine compound in one step under the condition of a triethylsilane and elemental iodine system at room temperature; the synthetic route map is specifically referred to Figure 1 , Figure 1 X, Y and Z can be H, F, Cl, Br, NH2, NO2 or OMe.

[0036] The reduction reaction process is specifically as follows: at room temperature, the aromatic nitro compound and the solvent are added into the reactor and stirred, after being dissolved, the triethylsilane and the elemental iodine are added into the reaction system; after the addition is completed, the stirring is continued, and the sample GC tracking is performed; after the reaction is stopped, the column chromatography is performed to separate the aromatic amine compound.

[0037] Specifically, in the reduction reaction, the molar ratio of the triethylsilane to the aromatic nitro compound is 8.0:1.0; the molar ratio of the elemental iodine to the aromatic nitro compound is 0.5:1.0; the solvent is dichloroethane; and the volume ratio of the solvent to the mass of the aromatic nitro compound is in the range of 8.0-15.0 mL:1.0 g.

[0038] Example 1

[0039] The synthetic route map is specifically referred to Figure 2 .

[0040] The reduction reaction process is specifically as follows: at room temperature, the aromatic nitro compound and the solvent are added into the reactor and stirred, after being dissolved, the triethylsilane and the elemental iodine are added into the reaction system; after the addition is completed, the stirring is continued, and the sample GC tracking is performed; after the reaction is stopped, the column chromatography is performed to separate the aromatic amine compound.

[0041] Example 2

[0042] The synthetic route map is specifically referred to Figure 3 .

[0043] The reduction reaction process is as follows: at room temperature, 315 mg of p-chloronitrobenzene and 4 mL of dichloroethane are added to the reactor, stirred, and after dissolution, 1.86 g of triethylsilane and 254 mg of iodine are added to the reaction system; after addition, continue to stir, sample GC tracking (adjust to alkaline with 1 N NaOH; sample conditions: column initial temperature: 150°C; temperature rising rate: 15°C / min); after the reaction stops, column chromatography is used to separate p-chloroaniline, and the reaction yield is 22%.

[0044] Example 3

[0045] The synthetic route is shown in detail with reference to Figure 4 .

[0046] The reduction reaction process is as follows: at room temperature, 315 mg of p-chloronitrobenzene and 4 mL of dichloroethane are added to the reactor, stirred, and after dissolution, 1.86 g of triethylsilane and 254 mg of iodine are added to the reaction system; after addition, continue to stir, sample GC tracking (adjust to alkaline with 1 N NaOH; sample conditions: column initial temperature: 150°C; temperature rising rate: 15°C / min); after the reaction stops, column chromatography is used to separate p-chloroaniline, and the reaction yield is 22%.

[0047] Example 4

[0048] The synthetic route is shown in detail with reference to Figure 5 .

[0049] The reduction reaction process is as follows: at room temperature, 315 mg of p-chloronitrobenzene and 4 mL of dichloroethane are added to the reactor, stirred, and after dissolution, 1.86 g of triethylsilane and 254 mg of iodine are added to the reaction system; after addition, continue to stir, sample GC tracking (adjust to alkaline with 1 N NaOH; sample conditions: column initial temperature: 150°C; temperature rising rate: 15°C / min); after the reaction stops, column chromatography is used to separate p-chloroaniline, and the reaction yield is 22%.

[0050] Example 5

[0051] The synthetic route is shown in detail with reference to Figure 6 .

[0052] The reduction reaction process is as follows: at room temperature, 315 mg of p-chloronitrobenzene and 4 mL of dichloroethane are added to the reactor, stirred, and after dissolution, 1.86 g of triethylsilane and 254 mg of iodine are added to the reaction system; after addition, continue to stir, sample GC tracking (adjust to alkaline with 1 N NaOH; sample conditions: column initial temperature: 150°C; temperature rising rate: 15°C / min); after the reaction stops, column chromatography is used to separate p-chloroaniline, and the reaction yield is 22%.

[0053] Example 6

[0054] The synthetic route map is specifically referred to Figure 7 .

[0055] The reduction reaction process is as follows: at room temperature, 384 mg of 3,4-dichloronitrobenzene and 4 mL of dichloroethane were added to the reactor, stirred, and after dissolution, 1.86 g of triethylsilane and 254 mg of iodine were added to the reaction system; after completion of the addition, stirring was continued, and GC tracking was performed (adjusted to alkaline with 1 N NaOH; injection conditions: column initial temperature: 150°C; temperature rising rate: 15°C / min); after the reaction stopped, column chromatography was used to separate 3,4-dichloroaniline, and the reaction yield was 93%.

[0056] Example 7

[0057] The synthetic route map is specifically referred to Figure 8 .

[0058] The reduction reaction process is as follows: at room temperature, 274 mg of o-nitrotoluene and 4 mL of dichloroethane were added to the reactor, stirred, and after dissolution, 1.86 g of triethylsilane and 254 mg of iodine were added to the reaction system; after completion of the addition, stirring was continued, and GC tracking was performed (adjusted to alkaline with 1 N NaOH; injection conditions: column initial temperature: 150°C; temperature rising rate: 15°C / min); after the reaction stopped, column chromatography was used to separate o-toluidine, and the reaction yield was 11%.

[0059] Example 8

[0060] The synthetic route map is specifically referred to Figure 9 .

[0061] The reduction reaction process is as follows: at room temperature, 342 mg of 2-chloro-4-nitrotoluene and 4 mL of dichloroethane were added to the reactor, stirred, and after dissolution, 1.86 g of triethylsilane and 254 mg of iodine were added to the reaction system; after completion of the addition, stirring was continued, and GC tracking was performed (adjusted to alkaline with 1 N NaOH; injection conditions: column initial temperature: 150°C; temperature rising rate: 15°C / min); after the reaction stopped, column chromatography was used to separate 3-chloro-4-methylaniline, and the reaction yield was 59%.

[0062] Example 9

[0063] The synthetic route map is specifically referred to Figure 10 .

[0064] The reduction reaction process is as follows: at room temperature, 306 mg of p-nitroanisole and 4 mL of dichloroethane are added to the reactor, stirred, and after dissolution, 1.86 g of triethylsilane and 254 mg of iodine are added to the reaction system; after completion of the addition, continue to stir, and sample GC tracking (adjust to alkaline with 1 N NaOH; sample conditions: column initial temperature: 150°C; temperature rising rate: 15°C / min); after the reaction stops, column chromatography is used to separate p-methoxyaniline, and the reaction yield is 71%.

[0065] Example 10

[0066] The synthetic route is shown in detail with reference to Figure 11 .

[0067] The reduction reaction process is as follows: at room temperature, 306 mg of p-nitroanisole and 4 mL of dichloroethane are added to the reactor, stirred, and after dissolution, 1.86 g of triethylsilane and 254 mg of iodine are added to the reaction system; after completion of the addition, continue to stir, and sample GC tracking (adjust to alkaline with 1 N NaOH; sample conditions: column initial temperature: 150°C; temperature rising rate: 15°C / min); after the reaction stops, column chromatography is used to separate p-methoxyaniline, and the reaction yield is 71%.

[0068] Example 11

[0069] The synthetic route is shown in detail with reference to Figure 12 .

[0070] The reduction reaction process is as follows: at room temperature, 306 mg of p-nitroanisole and 4 mL of dichloroethane are added to the reactor, stirred, and after dissolution, 1.86 g of triethylsilane and 254 mg of iodine are added to the reaction system; after completion of the addition, continue to stir, and sample GC tracking (adjust to alkaline with 1 N NaOH; sample conditions: column initial temperature: 150°C; temperature rising rate: 15°C / min); after the reaction stops, column chromatography is used to separate p-methoxyaniline, and the reaction yield is 71%.

[0071] Example 12

[0072] The synthetic route is shown in detail with reference to Figure 13 .

[0073] The reduction reaction process is as follows: at room temperature, 306 mg of p-nitroanisole and 4 mL of dichloroethane are added to the reactor, stirred, and after dissolution, 1.86 g of triethylsilane and 254 mg of iodine are added to the reaction system; after completion of the addition, continue to stir, and sample GC tracking (adjust to alkaline with 1 N NaOH; sample conditions: column initial temperature: 150°C; temperature rising rate: 15°C / min); after the reaction stops, column chromatography is used to separate p-methoxyaniline, and the reaction yield is 71%.

[0074] Example 13

[0075] The synthetic route is shown in detail with reference to Figure 14 .

[0076] The reduction reaction process is as follows: at room temperature, 476 mg of 2,6-difluoro-4-bromonitrobenzene and 4 mL of dichloroethane were added to the reactor, stirred, and after dissolution, 1.86 g of triethylsilane and 254 mg of iodine were added to the reaction system; after completion of the addition, stirring was continued, and sample GC tracking was performed (adjusted to alkaline with 1 N NaOH; injection conditions: column initial temperature: 180°C; temperature increase rate: 15°C / min); after the reaction was stopped, column chromatography was used to separate 2,6-difluoro-4-bromoaniline, and the reaction yield was 60%.

[0077] Example 14

[0078] The synthetic route is shown in detail with reference to Figure 15 .

[0079] The reduction reaction process is as follows: at room temperature, 470 mg of 2-fluoro-4-bromo-6-nitroaniline and 4 mL of dichloroethane were added to the reactor, stirred, and after dissolution, 1.86 g of triethylsilane and 254 mg of iodine were added to the reaction system; after completion of the addition, stirring was continued, and sample GC tracking was performed (adjusted to alkaline with 1 N NaOH; injection conditions: column initial temperature: 180°C; temperature increase rate: 15°C / min); after the reaction was stopped, column chromatography was used to separate 5-bromo-3-fluoro-1,2-phenylenediamine, and the reaction yield was 88%.

[0080] Example 15

[0081] The synthetic route is shown in detail with reference to Figure 16 .

[0082] The reduction reaction process is as follows: at room temperature, 414 mg of 2-nitro-4,5-dichloroaniline and 4 mL of dichloroethane were added to the reactor, stirred, and after dissolution, 1.86 g of triethylsilane and 254 mg of iodine were added to the reaction system; after completion of the addition, stirring was continued, and sample GC tracking was performed (adjusted to alkaline with 1 N NaOH; injection conditions: column initial temperature: 180°C; temperature increase rate: 15°C / min); after the reaction was stopped, column chromatography was used to separate 4,5-dichloro-1,2-phenylenediamine, and the reaction yield was 55%.

[0083] Example 16

[0084] The synthetic route is shown in detail with reference to Figure 17 .

[0085] The reduction reaction process is as follows: at room temperature, 440 mg of 3-fluoro-5-bromonitrobenzene and 4 mL of dichloroethane are added to the reactor, stirred, and after dissolution, 1.86 g of triethylsilane and 254 mg of iodine are added to the reaction system; after the addition, continue to stir, sample GC tracking (adjust to alkaline with 1N NaOH; injection conditions: column initial temperature: 120℃; temperature rising rate: 5℃ / min); after the reaction stops, column chromatography is used to separate 3-fluoro-5-bromoaniline, and the reaction yield is 85%.

[0086] Example 17

[0087] The synthesis route is specifically referred to Figure 18 .

[0088] The reduction reaction process is as follows: at room temperature, 464 mg of 2-bromo-5-nitroanisole and 4 mL of dichloroethane are added to the reactor, stirred, and after dissolution, 1.86 g of triethylsilane and 254 mg of iodine are added to the reaction system; after the addition, continue to stir, sample GC tracking (adjust to alkaline with 1N NaOH; injection conditions: column initial temperature: 180℃; temperature rising rate: 15℃ / min); no reaction.

[0089] In summary, the aromatic amine compound is obtained by using aromatic nitro compound as raw material, triethylsilane and iodine monomer system, and one-step reaction at room temperature. On the premise of obtaining good yield, the overall step operation is simple, the reaction process is mild, and it is easy to prepare.

[0090] The above is only a preferred embodiment of the present application, and therefore cannot limit the scope of the present application. Any equivalent changes and modifications made according to the scope of the present application and the content of the specification shall still be within the scope of the present application.

Claims

1. A method for preparing an aromatic amine compound, characterized in that: Aromatic nitro compounds were obtained in a one-step reaction using triethylsilane and iodine in a system at room temperature. The specific synthetic route is as follows: ； Where X, Y, and Z are H, F, Cl, Br, NH2, NO2, or OMe.

2. The method for preparing an aromatic amine compound according to claim 1, characterized in that: The reduction reaction process is as follows: At room temperature, aromatic nitro compounds and solvents are added to the reactor and stirred. After dissolution, triethylsilane and elemental iodine are added to the reaction system. After the addition is complete, stirring is continued, and samples are taken for GC tracking. After the reaction stops, aromatic amine compounds are separated by column chromatography.

3. The method for preparing an aromatic amine compound according to claim 2, characterized in that: During the reduction reaction, the molar ratio of triethylsilane to aromatic nitro compound used is 8.0:1.

0.

4. The method for preparing an aromatic amine compound according to claim 2, characterized in that: During the reduction reaction, the molar ratio of elemental iodine to aromatic nitro compounds used is 0.5:1.

0.

5. The method for preparing an aromatic amine compound according to claim 2, characterized in that: The solvent used in the reduction reaction is dichloroethane.

6. The method for preparing an aromatic amine compound according to claim 2, characterized in that: During the reduction reaction, the ratio of the volume of the solvent used to the mass of the aromatic nitro compound ranges from 8.0 to 15.0 mL: 1.0 g.

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