Process for the amination of aryl (hetero) cyclic methyl compounds to nitrile compounds

Abstract

The application provides a method for aminating an aromatic (hetero) ring methyl compound into a nitrile compound, which comprises the following steps: under normal pressure, a chloride, a metal salt or a mixture of the two is used as a catalyst, a salt of hydroxylamine is used as a nitrogen source, air or oxygen is used as an oxidant, and the aromatic (hetero) ring methyl compound is converted into a high-value-added nitrile in one step under light irradiation. The reaction process of the application does not involve chemical oxidants, the reaction conditions are mild, the conversion rate is high, and the catalyst is easy to recover. At present, there is no literature report on the use of cheap and readily available chloride, metal salt or mixture of the two as a catalyst for participating in the nitrification reaction of the photocatalyst. The safety, environmental protection, economy and social benefit of the application have remarkable advantages.

Description

Technical Field

[0001] This invention relates to the field of organic chemical synthesis, specifically to a method for ammoniating aromatic (hetero)cyclic methyl compounds into nitrile compounds. Background Technology

[0002] Aromatic nitrile compounds are important raw materials for fine chemicals and intermediates in organic synthesis, and are widely used in the synthesis of pharmaceuticals, pesticides, polymer materials, and other chemicals. Traditional synthetic methods for aromatic nitriles include the Sandmeyer reaction (J. Chem. Soc., Chem. Commun. 1984, 1523-1524.), the Rosenmund-von Braun reaction (J. Org. Chem. 1941, 06, 795-803.), and the dehydration reaction of aldoximes and primary amines (J. Org. Chem. 1973, 38, 1060-1061.). The diazonium salt method based on the Sandmeyer reaction is cumbersome and uses highly toxic heavy metal cyanide (J. Chem. Res. 2012, 36(10), 573-574; J. Appl. Polym. Sci. 2012, 125(3), 2163-2169.; Bull. Korean Chem. Soc. 2019, 40(10), 939-942.). The Rosenmund-von Braun reaction uses highly toxic heavy metal cyanide as the cyaniding reagent, resulting in serious waste pollution and high treatment costs (Chem. Rev. 1987, 87, 779-794.; Synlett. 2008, 2008(1), 69-72.); The dehydration reaction of aldoximes and primary amines requires prefunctionalization of raw materials, which is neither economical nor environmentally friendly (Angew. Chem. Int. Ed. 2007, 46(21), 3922-5.; Organometallics 2020, 39(6), 824-833.). In contrast, the direct ammoxidation of methyl aromatics is a more desirable strategy due to its atom and step economy. However, in the past few decades, the thermal ammoxidation technology developed based on the Sohio acrylonitrile synthesis method has only been applied to a limited number of bulk nitrile products (Nat. Rev. Chem. 2018, 2(1).; J. Polym Sci. 2020, 58(8), 1039-1061.), because thermal ammoxidation requires strict reaction conditions and complex equipment (Angew. Chem. Int. Ed. 2012, 51(29), 7250-3.; J. Am. Chem. Soc. 2016, 138(10), 3294-7; Nat. Commun. 2017, 8(1), 8.; Chem. Mater. 2018, 30(18), 6361-6369.). On the other hand, despite the continuous progress of photocatalysis technology, there are very few reports on the one-step conversion of methyl aromatics into aromatic nitriles.Among them, Singh's team developed a method to obtain nitrile compounds through a two-step process using an expensive 2,4,5,6-tetra(9h-carbazole-9-yl)isophthalonitrile (4CzIPN) catalyst and toxic NaN3 as a nitrogen source (Chemistry 2020, 26(62), 14070-14074). In addition, Konig and colleagues reported a one-step ammoxidation method that uses an organic dye (TPP, 2,4,6-triphenylpyrantetrafluoroborate) as a photocatalyst in the presence of NH2OHHCl and NH4Br under a 455 nm LED to obtain the corresponding nitrile compounds (Angew. Chem. Int. Ed. 2021, 60(5), 2439-2445.). To circumvent the challenge of CH bond activation, most research groups utilize more reactive raw materials, such as aryl alcohols, aryl formaldehydes, and arylmethyl primary amines, to achieve one-step photosynthesis of aryl nitriles (ACS Catal. 2014, 5(1), 34-38; ACS Sustainable Chem. Eng. 2017, 5(3), 2562-2577.; J. Am. Chem. Soc. 2022, 144(51), 23321-23331.; Sci. China Chem. 2023, 66(10), 2852-2857.). However, these methods are costly due to the need for expensive photosensitizers and raw materials, and therefore lack industrial application prospects.

[0003] Existing synthetic techniques for aromatic nitrile compounds have shortcomings, such as the need for high temperature, high pressure and demanding equipment in ammonia oxidation and similar processes, and the high cost and low catalytic efficiency of some catalysts in photocatalytic oxidation. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a method for ammoniating aromatic (hetero)cyclic methyl compounds into nitrile compounds, thus solving the problems mentioned in the background section.

[0005] The technical solution adopted in this invention is as follows:

[0006] A method for ammoniating aromatic (hetero)cyclic methyl compounds to nitrile compounds includes the following steps:

[0007] Aromatic (heterocyclic) methyl compounds are converted into high-value-added nitriles in one step under normal pressure, using chlorides, metal salts, or mixtures of both as catalysts, hydroxylamine salts as nitrogen sources, and air or oxygen as oxidants, and under light irradiation.

[0008] The reaction is represented by the following formula:

[0009]

[0010] In the formula:

[0011] Ar represents benzene rings and aromatic heterocycles. hv represents light conditions.

[0012] X can be: tert-butyl, phenyl, -OR, -OCOR, halogen (F,Cl), -CF3, -OCF3, -NHCOR;

[0013] Wherein, R represents: H, methyl, ethyl, or phenyl.

[0014] Further, the chloride is specifically one of the following: hydrochloric acid, ammonium chloride, ferric chloride, copper chloride, cerium chloride, dichloroethane, carbon tetrachloride, tetrabutylammonium chloride, and benzyltrimethylammonium chloride;

[0015] The metal salt is specifically one of the following: ferric sulfate, ferric trifluoromethanesulfonate, copper acetate, copper chloride, cerium trichloride, and zinc trifluoromethanesulfonate.

[0016] Furthermore, the salt of hydroxylamine is specifically one of hydroxylamine hydrochloride or hydroxylamine sulfate.

[0017] Further, the aromatic (heterocyclic) methyl compound is a substituted aromatic methyl compound or an aromatic heterocyclic methyl compound, wherein the aromatic ring is a benzene ring, naphthalene ring, or biphenyl with substituents such as -H, -OH, -OMe, -OEt, -OPh, -NHAc, -Ph, -F, -Cl, -CF3, or -OCF3;

[0018] Aromatic heterocycles: These are five-membered heterocycles containing sulfur, nitrogen, and oxygen, such as thiophene, furan, and pyrazole.

[0019] Furthermore, the reaction of the aromatic (hetero)cyclic methyl compound is carried out in a solvent, and the solvent is one of water, acetonitrile, tetrahydrofuran, monochlorobenzene, acetonitrile, and benzene, or a mixture of two or three of them.

[0020] Furthermore, the molar amount of the catalyst is 0.05 to 3.0 times that of the aromatic (hetero)cyclic methyl compound.

[0021] Furthermore, the molar amount of the hydroxylamine salt is 0.5 to 2.5 times that of the aromatic (hetero)cyclic methyl compound.

[0022] Furthermore, the reaction temperature is 10–80°C, and the reaction of the aromatic (heterocyclic) methyl compounds is carried out under illumination conditions with a light source wavelength range of 300–450 nm.

[0023] The beneficial effects of this invention are as follows: the reaction process of this invention does not involve chemical oxidants, the reaction conditions are mild, the conversion rate is high, and the catalyst is easy to recover. Currently, there are few reports in the literature on using inexpensive, readily available, and environmentally friendly chlorides, metal salts, or mixtures of both as catalysts for photocatalysis in nitrification reactions; it has significant advantages in terms of safety, environmental protection, economy, and social benefits. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the reaction structure of the present invention. Detailed Implementation

[0025] The present invention will be described in detail below with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in the present application can be combined with each other.

[0026] like Figure 1 As shown, according to one aspect of the present invention, a method for ammoniating aromatic (heterocyclic) methyl compounds to nitrile compounds is provided, wherein the aromatic (heterocyclic) methyl compounds are converted into high-value-added nitrile compounds in one step under light irradiation using a chloride, a metal salt, or a mixture of both as a catalyst, a hydroxylamine salt as a nitrogen source, and air or oxygen as an oxidant.

[0027] A method for ammoniating aromatic (hetero)cyclic methyl compounds to nitrile compounds includes the following steps:

[0028] S1. Catalyst dosage ratio: The amount of catalyst, such as chloride, metal salt, or a mixture of both, is 0.05 to 3.0 times (mol) of the aromatic (hetero)cyclic methyl compound.

[0029] S2. Adding a catalyst: Aromatic (hetero)cyclic methyl compounds use chlorides, metal salts, or a mixture of both as catalysts. Chlorides include hydrochloric acid, ammonium chloride, ferric chloride, copper chloride, cerium chloride, dichloroethane, carbon tetrachloride, tetrabutylammonium chloride, benzyltrimethylammonium chloride, and one of these can be selected as appropriate. Metal salts include ferric sulfate, ferric trifluoromethanesulfonate, copper acetate, copper chloride, cerium chloride, zinc trifluoromethanesulfonate, and one of these can be selected as appropriate.

[0030] S3. Nitrogen source dosage ratio: The amount of hydroxylamine in the nitrogen source is 0.5 to 2.5 times (mol) of the aromatic (hetero)cyclic methyl compound;

[0031] S4. Add a nitrogen source: The nitrogen source is hydroxylamine, including hydroxylamine hydrochloride and hydroxylamine sulfate, and one of them should be selected as appropriate.

[0032] S5. Reaction solvents for aromatic (hetero)cyclic methyl compounds: including water, acetonitrile, tetrahydrofuran, monochlorobenzene, acetonitrile, benzene, or a mixture of two or three of them;

[0033] S6. Irradiation and temperature conditions for the reaction of aromatic (heterocyclic) methyl compounds: The reaction temperature of aromatic (heterocyclic) methyl compounds is 10-80℃, and the reaction is carried out under illumination conditions with a light source wavelength range of 300-450nm.

[0034] S7. Synthesis of aromatic (heteronitrile) compounds: The products of the highly selective ammoxidation reaction of aromatic (hetero)cyclic methyl compounds are the corresponding aromatic (heteronitrile) compounds.

[0035] Combining the above steps:

[0036] Example 1: Synthesis of Benzonitrile

[0037] In a 25 mL quartz reaction tube containing a built-in magnetic stir bar, 1 mmol of ammonium chloride, 1 mmol of ferric sulfate, 1 mmol of hydroxylamine hydrochloride, 1 mmol of toluene, 1 mL of water, and 5 mL of acetonitrile were added sequentially. A three-way valve was connected to the tube to allow oxygen (air) to enter. Stirring was started, and the reaction solution was irradiated with ultraviolet light from a 50W LED lamp with a wavelength of 350–370 nm for 36 h. The reaction results were detected by gas chromatography-mass spectrometry. After removing the solvent peak, the remaining main products and their contents were: benzoic acid 15% and benzonitrile 81%. The reaction was stopped, 10 mL of ethyl acetate was added to the reaction solution, and the mixture was washed thoroughly with water (5 mL × 3). The reaction solution was extracted with ethyl acetate (10 mL × 3), and the organic layers were combined. The organic layers were dried with anhydrous sodium sulfate and excess organic solvent was removed by rotary evaporation. Finally, the mixture was purified by PTLC (EA:PE = 1:10) to obtain colorless oily benzonitrile (78.3 mg, separation yield 76%).

[0038] Example 2: Synthesis of o-hydroxybenzonitrile

[0039] In a 25 mL quartz reaction tube containing a built-in magnetic stir bar, 1 mmol of copper chloride, 1 mmol of ferric trifluoromethanesulfonate, 1 mmol of hydroxylamine hydrochloride, 1 mmol of o-hydroxytoluene, 1 mL of water, and 5 mL of acetonitrile were added sequentially. A three-way valve was connected to the tube to allow oxygen (air) to enter. Stirring was started, and the reaction solution was irradiated with 395 nm wavelength ultraviolet light from a 50 W LED lamp for 36 h. The reaction results were detected by gas chromatography-mass spectrometry. After removing the solvent peak, the remaining main products and their contents were: o-hydroxybenzoic acid 8% and o-hydroxybenzonitrile 86%. The reaction was stopped, 10 mL of ethyl acetate was added to the reaction solution, and the mixture was washed thoroughly with water (5 mL × 3). The reaction solution was extracted with ethyl acetate (10 mL × 3), and the organic layers were combined. The organic layers were dried with anhydrous sodium sulfate and excess organic solvent was removed by rotary evaporation. Finally, the product was purified by PTLC (EA:PE = 1:10) to obtain the product, a white solid o-hydroxybenzonitrile (88.1 mg, separation yield 74%).

[0040] Example 3: Synthesis of m-methoxybenzonitrile

[0041] In a 25 mL quartz reaction tube containing a built-in magnetic stir bar, 1 mmol of carbon tetrachloride, 1 mmol of cerium trichloride, 1 mmol of hydroxylamine hydrochloride, 1 mmol of m-methyl anisole, 1 mL of water, and 5 mL of acetonitrile were added sequentially. A three-way valve was connected to the tube to allow oxygen (air) to pass through. Stirring was started, and the reaction solution was irradiated with ultraviolet light from a 50W LED lamp with a wavelength of 350–370 nm for 36 h. The reaction results were detected by gas chromatography-mass spectrometry. After removing the solvent peak, the remaining main products and their contents were: m-methoxybenzoic acid 10% and m-methoxybenzonitrile 89%. The reaction was stopped, 10 mL of ethyl acetate was added to the reaction solution, and the mixture was washed thoroughly with water (5 mL × 3). The reaction solution was extracted with ethyl acetate (10 mL × 3), and the organic layers were combined. The organic layers were dried with anhydrous sodium sulfate and excess organic solvent was removed by rotary evaporation. Finally, the mixture was purified by PTLC (EA:PE = 1:5) to obtain a white solid m-methoxybenzonitrile (97.2 mg, separation yield 73%).

[0042] Example 4: Synthesis of p-chlorobenzonitrile

[0043] In a 25 mL colorless transparent reaction tube containing a built-in magnetic stir bar, 1 mmol of cerium trichloride, 1 mmol of ferric sulfate, 1 mmol of hydroxylamine sulfate, 1 mmol of p-chlorotoluene, 1 mL of water, and 5 mL of acetonitrile were added sequentially. A three-way valve was connected to the tube to allow oxygen (air) to pass through. Stirring was started, and the reaction solution was irradiated with ultraviolet light from a 50W LED lamp with a wavelength of 350–370 nm for 36 h. The reaction results were detected by gas chromatography-mass spectrometry. After removing the solvent peak, the remaining main products and their contents were: p-chlorobenzoic acid 8% and p-chlorobenzonitrile 89%. The reaction was stopped, 10 mL of ethyl acetate was added to the reaction solution, and the mixture was washed thoroughly with water (5 mL × 3). The reaction solution was extracted with ethyl acetate (10 mL × 3), and the organic layers were combined. The organic layers were dried over anhydrous sodium sulfate, and excess organic solvent was removed by rotary evaporation. Finally, the mixture was purified by PTLC (EA:PE = 1:10) to obtain a white solid p-chlorobenzonitrile (99.0 mg, separation yield 72%).

[0044] Example 5: Synthesis of 2,6-dichlorobenzonitrile

[0045] In a 25 mL colorless and transparent reaction tube containing a built-in magnetic stir bar, 1 mmol tetrabutylammonium chloride, 1 mmol ferric sulfate, 1 mmol hydroxylamine sulfate, 1 mmol 2,6-difluorotoluene, 1 mL water, and 5 mL acetonitrile were added sequentially. A three-way valve was connected to the tube to allow oxygen (air) to enter. Stirring was started, and the reaction solution was irradiated with ultraviolet light from a 50W LED lamp with a wavelength of 350–370 nm for 48 h. The reaction results were analyzed by gas chromatography-mass spectrometry. After subtracting the solvent peak, the remaining main products and their contents were: 10% 2,6-difluorobenzoic acid and 87% 2,6-difluorobenzonitrile. The reaction was stopped, 10 mL of ethyl acetate was added to the reaction solution, and the mixture was washed thoroughly with water (5 mL × 3). The reaction solution was extracted with ethyl acetate (10 mL × 3), and the organic layers were combined. The organic layers were dried with anhydrous sodium sulfate and excess organic solvent was removed by rotary evaporation. Finally, the mixture was purified by PTLC (EA:PE = 1:10) to obtain a white solid 2,6-difluorobenzonitrile (108.4 mg, separation yield 78%).

[0046] Example 6: Synthesis of 4-trifluoromethoxybenzonitrile

[0047] In a 25 mL quartz reaction tube containing a built-in magnetic stir bar, 1 mmol of benzyltrimethylammonium chloride, 1 mmol of copper acetate, 1 mmol of hydroxylamine hydrochloride, 1 mmol of 4-trifluoromethoxytoluene, 1 mL of water, and 5 mL of acetonitrile were added sequentially. A three-way valve was connected to the tube to allow oxygen (air) to enter. Stirring was started, and the reaction solution was irradiated with ultraviolet light from a 50W LED lamp with a wavelength of 350–370 nm for 32 h. The reaction results were analyzed by gas chromatography-mass spectrometry. After subtracting the solvent peak, the remaining main products and their contents were: 18% 4-trifluoromethoxybenzoic acid and 69% 4-trifluoromethoxybenzonitrile. The reaction was stopped, 10 mL of ethyl acetate was added to the reaction solution, and the mixture was washed thoroughly with water (5 mL × 3). The reaction solution was extracted with ethyl acetate (10 mL × 3), and the organic layers were combined. The organic layers were dried with anhydrous sodium sulfate and excess organic solvent was removed by rotary evaporation. Finally, the mixture was purified by PTLC (EA:PE = 1:10) to obtain a yellow oily 4-trifluoromethoxybenzonitrile (102.9 mg, separation yield 55%).

[0048] Example 7: Synthesis of 2-cyanonaphthalene

[0049] In a 25 mL colorless transparent reaction tube containing a built-in magnetic stir bar, 1 mmol of ammonium chloride, 1 mmol of cerium trichloride, 1 mmol of hydroxylamine hydrochloride, 1 mmol of 2-methylnaphthalene, 1 mL of water, and 5 mL of acetonitrile were added sequentially. A three-way valve was connected to the tube to allow oxygen (air) to enter. Stirring was started, and the reaction solution was irradiated with ultraviolet light from a 50W LED lamp with a wavelength of 350–370 nm for 36 h. The reaction results were detected by gas chromatography-mass spectrometry. After removing the solvent peak, the remaining main products and their contents were: 2-naphthoic acid 16% and 2-cyanonaphthalene 67%. The reaction was stopped, 10 mL of ethyl acetate was added to the reaction solution, and the mixture was washed thoroughly with water (5 mL × 3). The reaction solution was extracted with ethyl acetate (10 mL × 3), and the organic layers were combined. The organic layers were dried over anhydrous sodium sulfate and excess organic solvent was removed by rotary evaporation. Finally, the mixture was purified by PTLC (EA:PE = 1:5) to obtain a white solid 2-cyanonaphthalene (82.7 mg, yield 54%).

[0050] Example 8: Synthesis of terephthalonitrile

[0051] In a 25 mL quartz reaction tube containing a built-in magnetic stir bar, 1 mmol of dichloroethane, 1 mmol of zinc trifluoromethanesulfonate, 1 mmol of hydroxylamine sulfate, 1 mmol of p-toluenenitrile, 1 mL of water, and 5 mL of acetonitrile were added sequentially. A three-way valve was connected to the tube to allow oxygen (air) to enter. Stirring was started, and the reaction solution was irradiated with ultraviolet light from a 50W LED lamp with a wavelength of 350–370 nm for 32 h. The reaction results were detected by gas chromatography-mass spectrometry. After removing the solvent peak, the remaining main products and their contents were: p-cyanobenzoic acid 5% and terephthalonitrile 93%. The reaction was stopped, 10 mL of ethyl acetate was added to the reaction solution, and the mixture was washed thoroughly with water (5 mL × 3). The reaction solution was extracted with ethyl acetate (10 mL × 3), and the organic layers were combined. The organic layers were dried with anhydrous sodium sulfate, and excess organic solvent was removed by rotary evaporation. Finally, the mixture was purified by PTLC (EA:PE = 1:5) to obtain a white solid terephthalonitrile (107.6 mg, yield 84%).

[0052] Example 9: Highly Selective Ammoxidation of 5-Methylquinoline

[0053] In a 25 mL colorless transparent reaction tube containing a built-in magnetic stir bar, 1 mmol of copper chloride, 1 mmol of zinc trifluoromethanesulfonate, 1 mmol of hydroxylamine sulfate, 1 mmol of p-toluenenitrile, 1 mL of water, and 5 mL of acetonitrile were added sequentially. A three-way valve was connected to the tube to allow oxygen (air) to pass through. Stirring was started, and the reaction solution was irradiated with ultraviolet light from a 50W LED lamp with a wavelength of 350–370 nm for 28 h. The reaction results were detected by gas chromatography-mass spectrometry. After removing the solvent peak, the remaining main products and their contents were: 5% p-cyanobenzoic acid and 93% terephthalonitrile. The reaction was stopped, 10 mL of ethyl acetate was added to the reaction solution, and the mixture was washed thoroughly with water (5 mL × 3). The reaction solution was extracted with ethyl acetate (10 mL × 3), and the organic layers were combined. The organic layers were dried with anhydrous sodium sulfate, and excess organic solvent was removed by rotary evaporation. Finally, the mixture was purified by PTLC (EA:PE = 1:5) to obtain a white solid terephthalonitrile (107.6 mg, separation yield 84%).

[0054] Example 10: Synthesis of 4-cyano-1-methylpyrazole

[0055] In a 25 mL colorless, transparent reaction tube containing a built-in magnetic stir bar, add 1 mmol ammonium chloride, 1 mmol copper chloride, 1 mmol hydroxylamine hydrochloride, 1 mmol 1,4-dimethylpyrazole, 1 mL water, and 5 mL acetonitrile sequentially. Connect a three-way valve to the tube to allow oxygen (air) to enter. Start stirring and irradiate the reaction solution with a 50W LED lamp at a wavelength of 395 nm for 48 hours. Analyze the reaction results using gas chromatography-mass spectrometry. After subtracting the solvent peak, the remaining main products and their contents were: 1-methyl-4-pyrazole carboxylic acid 5%, 4-cyano-1-methylpyrazole 90%. The reaction was stopped, 10 mL of ethyl acetate was added to the reaction solution, and the mixture was washed thoroughly with water (5 mL × 3). The reaction solution was extracted with ethyl acetate (10 mL × 3), and the organic layers were combined. The organic layers were dried with anhydrous sodium sulfate and excess organic solvent was removed by rotary evaporation. Finally, the mixture was purified by PTLC (EA:PE = 1:5) to obtain a white solid 4-cyano-1-methylpyrazole (75.0 mg, separation yield 70%).

[0056] Example 11: Synthesis of 2-cyanobenzothiazole

[0057] In a 25 mL quartz reaction tube containing a built-in magnetic stir bar, 1 mmol of cerium trichloride, 1 mmol of copper chloride, 1 mmol of hydroxylamine sulfate, 1 mmol of 2-methylbenzothiazole, 1 mL of water, and 5 mL of acetonitrile were added sequentially. A three-way valve was connected to the tube to allow oxygen (air) to pass through. Stirring was started, and the reaction solution was irradiated with 395 nm wavelength ultraviolet light from a 50 W LED lamp for 48 h. The reaction results were detected by gas chromatography-mass spectrometry. After removing the solvent peak, the remaining main products and their contents were: benzothiazole-2-carboxylic acid 14%, 2-cyanobenzothiazole 67%. The reaction was stopped, 10 mL of ethyl acetate was added to the reaction solution, and the mixture was washed thoroughly with water (5 mL × 3). The reaction solution was extracted with ethyl acetate (10 mL × 3), and the organic layers were combined. The organic layers were dried over anhydrous sodium sulfate and excess organic solvent was removed by rotary evaporation. Finally, the mixture was purified by PTLC (EA:PE = 1:5) to obtain a white solid 2-cyanobenzothiazole (89.7 mg, yield 56%).

[0058] Example 12: Synthesis of 3,4-methylenedioxybenzonitrile

[0059] In a 25 mL colorless transparent reaction tube containing a built-in magnetic stir bar, 1 mmol of cerium trichloride, 1 mmol of zinc trifluoromethanesulfonate, 1 mmol of hydroxylamine hydrochloride, 1 mmol of 3,4-(methylenedioxy)toluene, 1 mL of water, and 5 mL of acetonitrile were added sequentially. A three-way valve was connected to the tube to allow oxygen (air) to enter. Stirring was started, and the reaction solution was irradiated with 395 nm UV light from a 50 W LED lamp for 48 h. The reaction results were analyzed by gas chromatography-mass spectrometry. After removing the solvent peak, the remaining main products and their contents were: 3,4-methylenedioxybenzoic acid 21% and 3,4-methylenedioxybenzonitrile 51%. The reaction was stopped, 10 mL of ethyl acetate was added to the reaction solution, and the mixture was washed thoroughly with water (5 mL × 3). The reaction solution was extracted with ethyl acetate (10 mL × 3), and the organic layers were combined. The organic layers were dried with anhydrous sodium sulfate and excess organic solvent was removed by rotary evaporation. Finally, the mixture was purified by PTLC (EA:PE = 1:5) to obtain a white solid 3,4-methylenedioxybenzonitrile (50.0 mg, separation yield 34%).

[0060] Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the examples given above. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of the present invention are also within the protection scope of the present invention.

Claims

1. A method for ammoniating aromatic ring methyl compounds to nitrile compounds, characterized in that: Includes the following steps: Aromatic methyl compounds can be converted into nitriles in one step under normal pressure, using a mixture of chloride and metal salt as a catalyst, hydroxylamine salt as a nitrogen source, and oxygen as an oxidant, under light irradiation. The reaction is represented by the following formula: In the formula: Ar represents the benzene ring; hv represents the light conditions. X is: tert-butyl, phenyl, -OR, -OCOR, -F, -Cl, -CF3, -OCF3, -NHCOR; Wherein, R represents: H, methyl, ethyl, phenyl; The chloride is specifically one of the following: hydrochloric acid, ammonium chloride, ferric chloride, dichloroethane, carbon tetrachloride, tetrabutylammonium chloride, and benzyltrimethylammonium chloride; The metal salt is specifically one of the following: ferric sulfate, ferric trifluoromethanesulfonate, copper acetate, copper chloride, cerium trichloride, and zinc trifluoromethanesulfonate.

2. The method for ammoniating aromatic ring methyl compounds to nitrile compounds according to claim 1, characterized in that: The salt of hydroxylamine is specifically one of hydroxylamine hydrochloride or hydroxylamine sulfate.

3. The method for ammoniating aromatic ring methyl compounds to nitrile compounds according to claim 1, characterized in that: The reaction of the aromatic heterocyclic methyl compound is carried out in a solvent, which is one of water, acetonitrile, tetrahydrofuran, monochlorobenzene, acetonitrile, and benzene, or a mixture of two or three of them.

4. The method for ammoniating aromatic ring methyl compounds to nitrile compounds according to claim 1, characterized in that: The molar amount of the catalyst is 0.05 to 3.0 times that of the aromatic methyl compound.

5. The method for ammoniating aromatic ring methyl compounds to nitrile compounds according to claim 2, characterized in that: The molar amount of the hydroxylamine salt is 0.5 to 2.5 times that of the aromatic ring methyl compound.

6. The method for ammoniating aromatic ring methyl compounds to nitrile compounds according to claim 1, characterized in that: The reaction temperature is 10–80 °C, and the reaction of the aromatic ring methyl compound is carried out under illumination conditions with a light source wavelength range of 300–450 nm.

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