Method for preparing aromatic nitrile compound by photo-initiation of nitro-cyanation of nitro-aromatic hydrocarbon

Abstract

The invention discloses a method for preparing an aromatic nitrile compound by photo-initiation of nitro-cyanation of nitro-aromatic hydrocarbon, and belongs to the technical field of organic synthesis. The method comprises the following steps: mixing nitro-aromatic hydrocarbon, a cyanation reagent and villiaumite in an organic solvent, and reacting at 25-55 DEG C under the irradiation of light with the wavelength of 365-450 nm to obtain the aromatic nitrile compound. According to the method disclosed by the invention, the denitrification cyanation of the nitro compound is realized through photo-initiation, the reaction conditions are simple, the used raw material reagents are few, the method has step economy and atom economy, the compatibility of substrate functional groups is good, and further derivatization of a converted product is facilitated to prepare complex functional molecules.

Description

Technical Field

[0001] The invention relates to the technical field of organic synthesis, and in particular to a method for preparing aromatic nitrile compounds by photoinduced denitration and cyanation of nitroaromatic hydrocarbons. Background Art

[0002] Aromatic nitro compounds are one of the cheapest and most readily available bulk chemicals. Nitro derivatives of various aromatic ring systems can be obtained by aromatic electrophilic nitration under certain conditions. How to efficiently increase the added value of nitroaromatics and their derivatives has always been one of the challenges for synthetic chemists. Converting the cheap and readily available carbon-nitrogen bond of nitrobenzene into other functional groups in one step is one of the most direct ways to increase its added value. There are relevant literature reports on the construction of CO, CS, CC and CN bonds by transition metal-catalyzed Suzuki cross-coupling reactions of aromatic nitro compounds. In 2017, the Nakao research group realized the cross-coupling reaction of non-activated nitrobenzene, and the construction of carbon-carbon bonds, carbon-nitrogen bonds and carbon-hydrogen bonds of nitrobenzene catalyzed by palladium was reported by the research group. However, there are few studies on the direct conversion of nitro groups to cyano groups to prepare aromatic nitrile compounds.

[0003] At present, there are two traditional conversion methods for aromatic nitro compounds to other aromatic compounds: one is to reduce nitrobenzene to obtain aromatic amines, and then construct carbon-carbon bonds or carbon-heteroatom bonds through diazotization and Sandmeyer reaction; the other is to convert nitro compounds containing electron-withdrawing groups into other aromatic compounds through aromatic nucleophilic substitution (S N The nitro group can be converted to other groups by the reaction of Ar). Among the above traditional transformations, the former has shortcomings in terms of step economy and atom economy, and the diazonium salt with explosion hazard needs to be handled during the reaction. The latter reaction substrate is limited to contain at least one electron-withdrawing group, and the substrate range is still limited. Summary of the invention

[0004] In view of the above deficiencies in the prior art, the present invention provides a method for preparing aromatic nitrile compounds by photoinduced denitration cyanation of nitroaromatic hydrocarbons, which is used to solve the problems of complex steps and narrow substrate application range in the prior art.

[0005] To achieve the above purpose, the specific technical solutions of the present invention are as follows:

[0006] A method for preparing aromatic nitrile compounds by photoinduced denitration and cyanation of nitroaromatic hydrocarbons, comprising: mixing nitroaromatic hydrocarbon I, a cyanation agent, and a fluoride salt in an organic solvent, and reacting under irradiation with light having a wavelength of 365 nm to 450 nm to obtain aromatic nitrile compounds II. The specific reaction equation is as follows:

[0007] ;

[0008] In the formula, Ar is a substituted or unsubstituted aromatic group or a heteroaromatic group.

[0009] Preferably, the cyanation reagent is selected from one or more of TMSCN, acetone cyanohydrin, NaCN, Cu(CN)2 or CDAP.

[0010] More preferably, the cyanation reagent is TMSCN.

[0011] Preferably, the substituent of the substituted aromatic group or heteroaromatic group is selected from one or more of halogen, cyano, hydroxyl, trifluoromethyl, alkyl, alkoxy, aryloxy, acyloxy, ester, acyl, thienyl, oxazolyl, phenyl or amide.

[0012] Further preferably, the substituent in the substituted aromatic group is a phenyl group; for biphenyl-type substrates, a higher product yield can be obtained at room temperature.

[0013] Preferably, the aromatic group is selected from one of phenyl, styryl or condensed ring aromatic groups, and the heteroaromatic group is selected from one of furyl, pyridyl, benzopyridyl, pyrazole, benzoxazolyl, benzofuranyl, dibenzofuranyl, isoquinolyl or quinolyl.

[0014] Preferably, the nitroaromatic hydrocarbon is selected from one of the following structures:

[0015] .

[0016] Preferably, the fluoride salt is selected from one of TBAF, KF or CsF.

[0017] Preferably, the molar ratio of the nitroaromatic hydrocarbon, the cyanation reagent and the fluoride salt is 1:(0.8-3):(0.8-4).

[0018] Preferably, the reaction temperature is 25-55°C.

[0019] Preferably, the organic solvent is acetonitrile.

[0020] Preferably, the reaction can be carried out in air or in an inert atmosphere.

[0021] Compared with the prior art, the present invention is beneficial in that:

[0022] The present invention uses nitroaromatic hydrocarbons and cyanation reagents as main raw materials, realizes the denitration cyanation of nitro compounds through photoinitiation, has mild reaction conditions, simple raw materials and reagents, has step economy, and has good compatibility of substrate functional groups, which is conducive to further derivatization of the conversion products to prepare complex functional molecules. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is the reaction mechanism diagram of denitrification cyanation in Example 2. DETAILED DESCRIPTION

[0024] The technical solution of the present invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] The present invention provides a method for preparing aromatic nitrile compounds by photoinduced denitration cyanation of nitroaromatic hydrocarbons, comprising: mixing nitroaromatic hydrocarbon I, a cyanation agent, and a fluoride salt in an organic solvent, and reacting under irradiation of light with a wavelength of 365 nm to 450 nm to obtain aromatic nitrile compounds II. The specific reaction equation is as follows:

[0026] ;

[0027] In the formula, Ar is a substituted or unsubstituted aromatic group or a heteroaromatic group.

[0028] In some examples, the cyanation reagent is selected from one or more of TMSCN, acetone cyanohydrin, NaCN, Cu(CN)2 or CDAP.

[0029] In some examples, the substituent of the substituted aromatic group or heteroaromatic group is selected from one or more of halogen, cyano, hydroxyl, trifluoromethyl, alkyl, alkoxy, aryloxy, acyloxy, ester, acyl, thienyl, oxazolyl, phenyl or amide.

[0030] In some examples, the aromatic group is selected from one of phenyl, styryl or condensed ring aromatic groups, and the heteroaromatic group is selected from one of furanyl, pyridyl, benzopyridyl, pyrazole, benzoxazolyl, benzofuranyl, dibenzofuranyl, isoquinolyl or quinolyl.

[0031] In some examples, the nitroarene is selected from one of the following structures:

[0032] ;

[0033] Accordingly, the aromatic nitrile compound is selected from one of the following structures:

[0034] .

[0035] In some examples, the fluoride salt is selected from one of TBAF, KF, or CsF.

[0036] In some examples, the molar ratio of the nitroaromatic hydrocarbon, the cyanation reagent, and the fluoride salt is 1:(0.8-3):(0.8-4).

[0037] In some examples, the reaction temperature is 25-55°C; the reaction of the present invention has a low reaction temperature and can be carried out at room temperature. As the temperature increases, the yield increases slightly.

[0038] In some examples, the reaction can be performed in air or in an inert atmosphere.

[0039] In the following specific examples, the light irradiation is used to excite and activate nitrobenzene, and TMSCN is used as a cyanation reagent in the presence of a fluoride salt to achieve denitration and cyanation of nitroaromatic hydrocarbons; the raw materials and reagents used in the examples are all commercially available.

[0040] Example 1

[0041] Preparation of 4'-trifluoromethyl-1,1'-biphenyl-4-carbonitrile

[0042] The specific reaction formula is as follows:

[0043]

[0044] The specific preparation process is as follows:

[0045] In an argon atmosphere, 4-nitro-4'-trifluoromethyl-1,1'-biphenyl (26.7 mg, 0.10 mol, 1.0 equiv.) and 1.0 mL of acetonitrile were added to a reaction flask, followed by TMSCN (38 μL, 3.0 equiv.) and TBAF (0.4 mL, 4.0 equiv., 1.0 M in THF) to obtain a reaction mixture. The reaction mixture was then placed under 390 nm LEDs and stirred at room temperature for 48 hours. The mixture was transferred to a flask containing ethyl acetate, and the volatiles were removed under vacuum to obtain a residue. The residue was purified by silica gel flash column chromatography using a hexane / ethyl acetate mixture as the eluent to obtain a colorless solid product, 4'-trifluoromethyl-1,1'-biphenyl-4-carbonitrile (18.3 mg, 74% yield).

[0046] On a silica gel thin layer plate using n-hexane-ethyl acetate as the developing solvent (the volume ratio of n-hexane to ethyl acetate was 30:1), the Rf of the product was measured to be 0.3.

[0047] The structural characterization data of the product are as follows:

[0048] 1H NMR (400 MHz, CDCl3, 25 ℃, δ): 7.78 – 7.74 (m, 4H), 7.71 – 7.69 (m, 4H) ppm.

[0049] 13 C NMR (100 MHz, CDCl3, 25 ℃, δ): 144.1, 142.7, 132.8, 130.7 (q, J =32.7 Hz), 126.1 (q, J = 3.8 Hz), 124.0 (q, J = 270.5 Hz), 118.6, 112.0 ppm.

[0050] 19 F NMR (376 MHz, CDCl3, 25 °C, δ): – 62.6 ppm.

[0051] HRMS-EI(m / z) calc'd for C 14 H9F3N + [M+H] + , 248.0682; found, 248.0684.

[0052] Example 2

[0053] Preparation of 1,1'-biphenyl-4-carbonitrile

[0054]

[0055] The specific preparation process is as follows:

[0056] In an argon atmosphere, 4-nitro-1,1'-biphenyl (19.9 mg, 0.10 mol, 1.0 equiv) and 1.0 mL of acetonitrile were added to a reaction flask, followed by TMSCN (13 μL, 1.0 equiv) and TBAF (0.1 mL, 1.0 equiv, 1.0 M inTHF) to obtain a reaction mixture. The reaction mixture was then placed under 390 nm LEDs and stirred at room temperature for 36 hours. The mixture was then transferred to a flask filled with ethyl acetate, and the volatiles were removed under vacuum to obtain a residue. The residue was purified by silica gel flash column chromatography using a hexane / ethyl acetate mixture as the eluent to obtain a colorless solid product, 1,1'-biphenyl-4-carbonitrile (12.4 mg, 69% yield).

[0057] On a silica gel thin layer plate, using n-hexane-ethyl acetate as the developing solvent (the volume ratio of n-hexane to ethyl acetate was 20:1), the Rf of the product was measured to be 0.3.

[0058] The structural characterization data of the product are as follows:

[0059] 1 H NMR (400 MHz, CDCl3, 25 ℃, δ): 7.78 – 7.71 (m, 4H), 7.64 (d, J =7.2 Hz, 2H), 7.54 – 7.47 (m, 3H) ppm.

[0060] 13 C NMR (100 MHz, CDCl3, 25 ℃, δ): 145.7, 139.2, 132.6, 129.1, 128.7,127.8, 127.2, 118.9, 110.9 ppm.

[0061] HRMS-EI(m / z) calc'd for C 13 HkDJ + [M+Na] + , 202.0627; found, 202.0629.

[0062] The inventors studied the reaction mechanism of denitration cyanation in Example 2 by DFT calculation (reaction mechanism as shown in Figure 1 As shown in Figure 2, the results show that the cyanide anion produced by the reaction of tetrabutylammonium fluoride with trimethylsilyl cyanide and the excited nitroaromatic hydrocarbon undergoes cooperative nucleophilic substitution to generate cyanide products. The energy barrier of this process is 41.3 kcal / mol, indicating that it cannot occur in the absence of light. After light excitation, it is calculated that the nitrobiphenyl substrate undergoes adiabatic excitation to reach the lowest singlet excited state (S1). Unlike S0, the two phenyl rings in S1 are almost coplanar (φ (C6’-C1’-C6-C1) = -6.1°), thereby extending the conjugation over the entire molecule. S1 then undergoes intersystem crossing (ISC) to generate the triplet nitro diradical T2. According to Kasha's rule, T2 rapidly undergoes internal transformation to form T1, in which the two radicals are delocalized to the phenyl ring. T1 then interacts with the generated tetrabutylammonium cyanide to form 3 D CN , 3 D CN Further substitution reaction occurs. Different from the ground state, 3 D CNThe cyanide substitution reaction occurs stepwise, first forming the Meisenheime intermediate 3 E CN , then tetrabutylammonium nitrite from 3 D CN The energy barrier of the substitution reaction in the excited state is only 5.7 kcal / mol, which is much lower than the energy barrier of the ground state and can be easily overcome under the reaction conditions. Further analysis shows that 3 D CN The nitro group in the phenyl group deviates from the phenyl plane by 18.3 o , which weakens their conjugation and activates the substrate for substitution reactions. 1 C CN The substrate in is not activated because the nitro group remains coplanar with the phenyl ring. 1 C CN and 3 3 D CN The structural differences between the two can be attributed to the electrophilicity of the reactive carbon C4. In the ground state, the C4 atom of the nitrobiphenyl substrate is almost neutral (NBO charge: 0.06), so it does not interact with the cyano group. In the excited state, the C4 atom of the nitrobiphenyl substrate becomes more electrophilic, such as the charge increases (NBO charge: 0.190 for T1), which promotes the interaction with the cyano group, which in turn distorts the planar structure of the nitrobiphenyl.

[0063] Example 3

[0064] Preparation of 4'-Fluoro-1,1'-biphenyl-4-carbonitrile

[0065] The specific reaction formula is as follows:

[0066]

[0067] The specific preparation process is as follows:

[0068] In an argon atmosphere, 4-fluoro-4'-nitro-1,1'-biphenyl (21.7 mg, 0.10 mol, 1.0 equiv) and 1.0 mL of acetonitrile were added to a reaction flask, followed by TMSCN (38 μL, 3.0 equiv) and TBAF (0.4 mL, 4.0 equiv, 1.0M in THF) to obtain a reaction mixture. The reaction mixture was then placed under 390 nm LEDs and stirred at room temperature for 48 hours. The mixture was then transferred to a flask filled with ethyl acetate, and the volatiles were removed under vacuum to obtain a residue. The residue was purified by silica gel flash column chromatography, with the eluent being a hexane / ethyl acetate mixture, to obtain a colorless solid product 4'-fluoro-1,1'-biphenyl-4-carbonitrile (14.8 mg, 75% yield).

[0069] On a silica gel thin layer plate, using n-hexane-ethyl acetate as the developing solvent (the volume ratio of n-hexane to ethyl acetate was 20:1), the Rf of the product was measured to be 0.3.

[0070] The structural characterization data of the product are as follows:

[0071] 1 H NMR (400 MHz, CDCl3, 25 ℃, δ): 7.72 (d, J = 8.0 Hz, 2H), 7.63 (d,J = 8.0 Hz, 2H), 7.58 – 7.54 (m, 2H), 7.19 – 7.15 (m, 2H) ppm.

[0072] 13 C NMR (100 MHz, CDCl3, 25 ℃, δ): 163.2 (d, J = 248.0 Hz), 144.6,135.3 (d, J = 3.2 Hz), 132.7, 128.9 (d, J = 8.2 Hz), 127.6, 118.8, 116.1 (d,J = 21.6 Hz), 111.0 ppm.

[0073] 19 F NMR (400 MHz, CDCl3, 25 ℃, δ): – 113.2 ppm

[0074] HRMS-EI(m / z) calc'd for C 13 H9FN + [M+H] + , 198.0714; found, 198.0716.

[0075] Example 4

[0076] Preparation of 4'-chloro-1,1'-biphenyl-4-carbonitrile

[0077] The specific reaction formula is as follows:

[0078]

[0079] The specific preparation process is as follows:

[0080] In an argon atmosphere, 4-chloro-4'-nitro-1,1'-biphenyl (23.3 mg, 0.10 mol, 1.0 equiv) and 1.0 mL of acetonitrile were added to a reaction flask, followed by TMSCN (38 μL, 3.0 equiv) and TBAF (0.4 mL, 4.0 equiv, 1.0M in THF) to obtain a reaction mixture. The reaction mixture was then placed under 390 nm LEDs and stirred at room temperature for 48 hours. The mixture was then transferred to a flask filled with ethyl acetate, and the volatiles were removed under vacuum to obtain a residue. The residue was purified by silica gel flash column chromatography, with the eluent being a hexane / ethyl acetate mixture, to obtain a colorless solid product, 4'-chloro-1,1'-biphenyl-4-carbonitrile (14.5 mg, 68% yield).

[0081] On a silica gel thin layer plate, using n-hexane-ethyl acetate as the developing solvent (the volume ratio of n-hexane to ethyl acetate was 20:1), the Rf of the product was measured to be 0.3.

[0082] The structural characterization data of the product are as follows:

[0083] 1 H NMR (400 MHz, CDCl3, 25 ℃, δ): 7.72 (d, J = 8.4 Hz, 2H), 7.54 (d, J = 8.4 Hz, 2H), 7.52 (d, J = 8.4 Hz, 2H), 7.45 (d, J = 8.4 Hz, 2H) ppm.

[0084] 13 C NMR (100 MHz, CDCl3, 25 ℃, δ): 144.4, 137.6, 135.0, 132.7, 129.4,128.5, 127.6, 118.8, 111.3 ppm.

[0085] HRMS-ESI(m / z) calc'd for C 13 H9ClN + [M+H] + , 214.0418; found, 214.0421.

[0086] Example 5

[0087] Preparation of 4'-bromo-1,1'-biphenyl-4-carbonitrile

[0088] The specific reaction formula is as follows:

[0089]

[0090] The specific preparation process is as follows:

[0091] In an argon atmosphere, 4-bromo-4'-nitro-1,1'-biphenyl (22.7 mg, 0.10 mol, 1.0 equiv) and 1.0 mL of acetonitrile were added to a reaction flask, followed by TMSCN (38 μL, 3.0 equiv) and TBAF (0.4 mL, 4.0 equiv, 1.0M in THF) to obtain a reaction mixture. The reaction mixture was then placed under 390 nm LEDs and stirred at room temperature for 48 hours. The mixture was then transferred to a flask filled with ethyl acetate, and the volatiles were removed under vacuum to obtain a residue. The residue was purified by silica gel flash column chromatography, with the eluent being a hexane / ethyl acetate mixture, to obtain a colorless solid product, 4'-bromo-1,1'-biphenyl-4-carbonitrile (20.0 mg, 78% yield).

[0092] On a silica gel thin layer plate, using n-hexane-ethyl acetate as the developing solvent (the volume ratio of n-hexane to ethyl acetate was 20:1), the Rf of the product was measured to be 0.3.

[0093] The structural characterization data of the product are as follows:

[0094] 1 H NMR (400 MHz, CDCl3, 25 ℃, δ): 7.74 – 7.72 (m, 2H), 7.66 – 7.60 (m, 4H), 7.47 – 7.44 (m, 2H) ppm.

[0095] 13 C NMR (100 MHz, CDCl3, 25 ℃, δ): 144.4, 138.1, 132.7, 132.2, 128.8,127.6, 123.2, 118.8, 111.3 ppm.

[0096] HRMS-EI(m / z) calc'd for C 13 H9BrN + [M+H] + , 257.9913; found, 257.9916.

[0097] Example 6

[0098] Preparation of 4'-iodo-1,1'-biphenyl-4-carbonitrile

[0099] The specific reaction formula is as follows:

[0100]

[0101] The specific preparation process is as follows:

[0102] In an argon atmosphere, 4-iodo-4'-nitro-1,1'-biphenyl (32.5 mg, 0.10 mol, 1.0 equivalent) and 1.0 mL of acetonitrile were added to a reaction flask, followed by TMSCN (38 μL, 3.0 equivalent) and TBAF (0.4 mL, 4.0 equivalent, 1.0M in THF) to obtain a reaction mixture. The reaction mixture was then placed under 390 nm LEDs and stirred at room temperature for 48 hours. The mixture was then transferred to a flask filled with ethyl acetate, and the volatiles were removed under vacuum to obtain a residue. The residue was purified by silica gel flash column chromatography, with the eluent being a hexane / ethyl acetate mixture, to obtain a colorless solid product, 4'-fluoro-1,1'-biphenyl-4-carbonitrile (18.9 mg, 62% yield).

[0103] On a silica gel thin layer plate, using n-hexane-ethyl acetate as the developing solvent (the volume ratio of n-hexane to ethyl acetate was 20:1), the Rf of the product was measured to be 0.3.

[0104] The structural characterization data of the product are as follows:

[0105] 1 H NMR (400 MHz, CDCl3, 25 ℃, δ): 7.81 (d, J = 8.0 Hz, 2H), 7.72 (d, J = 8.0 Hz, 2H), 7.64 (d, J = 8.0 Hz, 2H), 7.32 (d, J = 8.0 Hz, 2H) ppm.

[0106] 13 C NMR (100 MHz, CDCl3, 25 ℃, δ): 144.4, 138.1, 132.8, 132.3, 128.8,127.6, 123.2, 118.8, 111.3 ppm.

[0107] HRMS-ESI(m / z) calc'd for C 13 H9IN + [M+H] + , 305.9774; found, 305.9776.

[0108] Example 7

[0109] Preparation of 4'-cyclopropyl-1,1'-biphenyl-4-carbonitrile

[0110] The specific reaction formula is as follows:

[0111]

[0112] The specific preparation process is as follows:

[0113] In an argon atmosphere, 4-cyclopropyl-4'-nitro-1,1'-biphenyl (23.9 mg, 0.10 mol, 1.0 equiv.) and 1.0 mL of acetonitrile were added to a reaction flask, followed by TMSCN (38 μL, 3.0 equiv.) and TBAF (0.4 mL, 4.0 equiv., 1.0 M in THF) to obtain a reaction mixture. The reaction mixture was then placed under 390 nm LEDs and stirred at room temperature for 48 hours. The mixture was then transferred to a flask filled with ethyl acetate, and the volatiles were removed under vacuum to obtain a residue. The residue was purified by silica gel flash column chromatography using a hexane / ethyl acetate mixture as the eluent to obtain a colorless solid product, 4'-cyclopropyl-1,1'-biphenyl-4-carbonitrile (16.4 mg, 75% yield).

[0114] On a silica gel thin layer plate using hexane-ethyl acetate as the developing solvent (the volume ratio of hexane to ethyl acetate was 20:1), the Rf of the product was measured to be 0.2.

[0115] The structural characterization data of the product are as follows:

[0116] 1 H NMR (400 MHz, CDCl3, 25 ℃, δ): 7.75 – 7.68 (m, 4H), 7.52 (d, J =8.4 Hz, 2H), 7.52 (d, J = 8.0 Hz, 2H), 2.03 – 1.96 (m, 1H), 1.10 – 1.05 (m, 2H), 0.82 – 0.78 (m, 2H) ppm.

[0117] 13C NMR (100 MHz, CDCl3, 25 ℃, δ): 146.5, 146.1, 136.1, 132.6, 127.4,126.3, 119.1, 110.5, 15.3, 9.7 ppm.

[0118] HRMS-ESI(m / z) calc'd for C 16 H 14 N + [M+H] + , 220.1122; found, 220.1121.

[0119] Example 8

[0120] Preparation of 4'-trimethylsilyl-1,1'-biphenyl-4-carbonitrile

[0121] The specific reaction formula is as follows:

[0122]

[0123] The specific preparation process is as follows:

[0124] In an argon atmosphere, 4-trimethylsilyl-4'-nitro-1,1'-biphenyl (32.5 mg, 0.10 mol, 1.0 equiv) and 1.0 mL of acetonitrile were added to a reaction flask, followed by TMSCN (38 μL, 3.0 equiv) and TBAF (0.4 mL, 4.0 equiv, 1.0 M in THF) to obtain a reaction mixture. The reaction mixture was then placed under 390 nm LEDs and stirred at room temperature for 48 hours. The mixture was then transferred to a flask filled with ethyl acetate, and the volatiles were removed under vacuum to obtain a residue. The residue was purified by silica gel flash column chromatography using a hexane / ethyl acetate mixture as the eluent to obtain a colorless solid product, 4'-trimethylsilyl-1,1'-biphenyl-4-carbonitrile (21.3 mg, 85% yield).

[0125] On a silica gel thin layer plate using hexane-ethyl acetate as the developing solvent (the volume ratio of hexane to ethyl acetate was 30:1), the Rf of the product was measured to be 0.3.

[0126] The structural characterization data of the product are as follows:

[0127] 1 H NMR (400 MHz, CDCl3, 25 ℃, δ): 7.70 (dd, J = 15.6, 8.0 Hz, 4H),7.64 (d, J = 8.0 Hz, 2H), 7.57 (d, J = 8.0 Hz, 2H), 0.31 (s, 9H) ppm.

[0128] 13 C NMR (100 MHz, CDCl3, 25 ℃, δ): 146.8, 142.4, 140.6, 135.3, 133.8,128.9, 127.6, 120.1, 112.1, 0.0 ppm.

[0129] HRMS-EI(m / z) calc'd for C 16 H 18 NSi + [M+H] + , 252.1203; found, 252.1206.

[0130] Example 9

[0131] Preparation of 4-phenylethynylbenzonitrile

[0132]

[0133] The specific preparation process is as follows:

[0134] In an argon atmosphere, 1-nitro-4-phenylethynylbenzene (22.3 mg, 0.10 mol, 1.0 equiv) and 1.0 mL of acetonitrile were added to a reaction flask, followed by TMSCN (38 μL, 3.0 equiv) and TBAF (0.4 mL, 4.0 equiv, 1.0 M inTHF) to obtain a reaction mixture. The reaction mixture was then placed under 390 nm LEDs and stirred at room temperature for 48 hours. The mixture was then transferred to a flask filled with ethyl acetate, and the volatiles were removed under vacuum to obtain a residue. The residue was purified by silica gel flash column chromatography using a hexane / ethyl acetate mixture as the eluent to obtain a colorless solid product, 4-phenylethynylbenzonitrile (12.3 mg, 61% yield).

[0135] On a silica gel thin layer plate using hexane-ethyl acetate as the developing solvent (the volume ratio of hexane to ethyl acetate was 30:1), the Rf of the product was measured to be 0.3.

[0136] The structural characterization data of the product are as follows:

[0137] 1 H NMR (400 MHz, CDCl3, 25 ℃, δ): 7.62 (dd,J = 13.6, 8.0 Hz, 4H),7.75 – 7.54 (m, 2H), 7.40 – 7.35 (m, 3H) ppm.

[0138] 13 C NMR (100 MHz, CDCl3, 25 ℃, δ): 132.1, 132.0, 131.8, 129.2, 128.5,128.3, 122.2, 118.6, 111.5, 93.8, 87.7 ppm.

[0139] HRMS-EI(m / z) calc'd for C 15 HkDJ + [M+Na] + , 226.0627; found, 226.0626.

[0140] Example 10

[0141] Preparation of 9,9-dimethyl-9H-fluorene-2-carbonitrile

[0142] The specific reaction formula is as follows:

[0143]

[0144] In an argon atmosphere, 9,9-dimethyl-2-nitro-9H-fluorene (23.9 mg, 0.10 mol, 1.0 equivalent) and 1.0 mL of acetonitrile were added to a reaction bottle, followed by TMSCN (38 μL, 3.0 equivalent) and TBAF (0.4 mL, 4.0 equivalent, 1.0M in THF) to obtain a reaction mixture. The reaction mixture was then placed under 390 nm LEDs and stirred at room temperature for 48 hours. The mixture was then transferred to a flask filled with ethyl acetate, and the volatiles were removed under vacuum to obtain a residue. The residue was purified by silica gel flash column chromatography, with the eluent being a hexane / ethyl acetate mixture, to obtain a colorless solid product, 9,9-dimethyl-9H-fluorene-2-carbonitrile (11.4 mg, 52% yield).

[0145] On a silica gel thin layer plate using hexane-ethyl acetate as the developing solvent (the volume ratio of hexane to ethyl acetate was 40:1), the Rf of the product was measured to be 0.3.

[0146] The structural characterization data of the product are as follows:

[0147] 1H NMR (400 MHz, CDCl3, 25 ℃, δ): 7.79 – 7.76 (m, 2H),7.70 (s, 1H),7.63 (d, J = 7.6 Hz, 1H), 7.48 – 7.47 (m, 1H), 7.43 – 7.37 (m, 2H), 1.50 (s,6H) ppm.

[0148] 13 C NMR (100 MHz, CDCl3, 25 ℃, δ): 154.2, 154.1, 143.9, 137.3, 131.5,129.1, 127.5, 126.5, 122.9, 121.1, 120.6, 119.7, 110.1, 47.2, 26.8 ppm. Onecarbon is missing because of overlap.

[0149] HRMS-ESI(m / z) calc'd for C 16 H 14 N + [M+H] + , 220.1121; found, 220.1117.

[0150] Embodiment 11

[0151] Preparation of 9H-fluorene-2-carbonitrile

[0152] The specific reaction formula is as follows:

[0153]

[0154] The specific preparation process is as follows:

[0155] In an argon atmosphere, 2-nitro-9H-fluorene (21.1 mg, 0.10 mol, 1.0 equiv) and 1.0 mL of acetonitrile were added to a reaction flask, followed by TMSCN (38 μL, 3.0 equiv) and TBAF (0.4 mL, 4.0 equiv, 1.0 M in THF) to obtain a reaction mixture. The reaction mixture was then placed under 390 nm LEDs and stirred at room temperature for 48 hours. The mixture was then transferred to a flask filled with ethyl acetate, and the volatiles were removed under vacuum to obtain a residue. The residue was purified by silica gel flash column chromatography using a hexane / ethyl acetate mixture as the eluent to obtain a colorless solid product 9H-fluorene-2-carbonitrile (11.5 mg, 60% yield).

[0156] The structural characterization data of the product are as follows:

[0157] 1 H NMR (400 MHz, CDCl3, 25 ℃, δ): 7.85 – 7.81 (m, 3H), 7.68 (d, J =8.0 Hz, 1H), 7.62 (d, J = 6.8 Hz, 1H), 7.49 – 7.42 (m, 2H), 3.94 (s, 2H) ppm.

[0158] 13 One carbon missing because of overlap.

[0159] 19 F NMR (400 MHz, CDCl3, 25 ℃, δ): – 63.1 ppm

[0160] HRMS-EI(m / z) calc'd for C 14 H 10 N + [M+H] + , 192.0808; found, 192.0811.

[0161] Example 12

[0162] Preparation of 5-phenyl-1-naphthocarbonitrile

[0163] The specific reaction formula is as follows:

[0164]

[0165] The specific preparation process is as follows:

[0166] In an argon atmosphere, 1-nitro-5-phenylnaphthalene (24.9 mg, 0.10 mol, 1.0 equiv) and 1.0 mL of acetonitrile were added to a reaction flask, followed by TMSCN (38 μL, 3.0 equiv) and TBAF (0.4 mL, 4.0 equiv, 1.0 M inTHF) to obtain a reaction mixture. The reaction mixture was then placed under 390 nm LEDs and stirred at room temperature for 5 hours. The mixture was then transferred to a flask containing ethyl acetate, and the volatiles were removed under vacuum to obtain a residue. The residue was purified by silica gel flash column chromatography using a hexane / ethyl acetate mixture as the eluent to obtain a colorless solid product, 5-phenyl-1-naphthalenecarbonitrile (13.3 mg, 58% yield).

[0167] On a silica gel thin layer plate using hexane-ethyl acetate as the developing solvent (the volume ratio of hexane to ethyl acetate was 50:1), the Rf of the product was measured to be 0.3.

[0168] The structural characterization data of the product are as follows:

[0169] 1 H NMR (400 MHz, CDCl3, 25 ℃, δ): 8.30 (s, 1H), 7.98 (d, J = 8.8 Hz,1H), 7.91 (d, J = 8.0 Hz, 1H), 7.66 (t, J = 7.2 Hz, 1H), 7.60 – 7.58 (m, 1H), 7.56 – 7.50 (m, 3H), 7.48 – 7.44 (m, 3H), ppm.

[0170] 13 C NMR (100 MHz, CDCl3, 25 ℃, δ): 140.7, 139.5, 134.5, 133.0, 132.7, 130.0, 128.6, 128.1, 127.9, 127.6, 127.3, 126.5, 119.3 ppm.

[0171] HRMS-ESI(m / z) calc'd for C 17 H 12 N + [M+H] + , 230.0964; found, 230.0957.

[0172] Embodiment 13

[0173] Preparation of methyl 2-(4'-cyano-2-fluoro-1,1'-biphenyl-4-yl) propionate

[0174] The specific reaction formula is as follows:

[0175]

[0176] The specific preparation process is as follows:

[0177] In an argon atmosphere, methyl 2-(2-fluoro-4'-nitro-1,1'-biphenyl-4-yl)propanoate (303.0 mg, 1.0 mol, 1.0 equiv) and 1.0 mL of acetonitrile were added to a reaction flask, followed by TMSCN (0.14 mL, 1.1 equiv) and TBAF (1.1 mL, 1.1 equiv, 1.0 M in THF) to obtain a reaction mixture. The reaction mixture was then placed under 390 nm LEDs and stirred at room temperature for 24 hours. The mixture was then transferred to a flask filled with ethyl acetate, and the volatiles were removed under vacuum to obtain a residue. The residue was purified by silica gel flash column chromatography using a hexane / ethyl acetate mixture as the eluent to obtain a colorless solid product methyl 2-(4'-cyano-2-fluoro-1,1'-biphenyl-4-yl)propanoate (162.0 mg, 57% yield).

[0178] On a silica gel thin layer plate using hexane-ethyl acetate as the developing solvent (the volume ratio of hexane to ethyl acetate was 20:1), the Rf of the product was measured to be 0.3.

[0179] The structural characterization data of the product are as follows:

[0180] 1 H NMR (400 MHz, CDCl3, 25 ℃, δ): 7.74 – 7.72 (m, 2H), 7.67 – 7.65 (m, 2H), 7.43 – 7.39 (m, 1H), 7.24 – 7.18 (m, 2H), 3.84 – 3.79 (m, 1H), 3.72(d, J = 4.0 Hz, 3H), 1.56 (d, J = 7.2 Hz, 3H) ppm.

[0181] 13 C NMR (100 MHz, CDCl3, 25 ℃, δ): 174.2, 159.6 (d, J = 248.0 Hz),143.5 (d, J= 8.0 Hz), 140.1, 132.3, 130.6 (d, J = 3.0 Hz), 129.6 (d, J = 3.0 Hz),125.8 (d, J = 13 Hz), 124.0 (d, J = 3.0 Hz), 123.7, 118.8, 115.6 (d, J = 23.0 Hz),111.4, 52.3, 44.9, 18.4 ppm.

[0182] 19 F NMR (376 MHz, CDCl3, 25 ℃, δ): – 117.0 (m) ppm

[0183] HRMS-EI(m / z) calc'd for C 17 H 13 FNO2 + [MH] + , 282.0936; found, 282.0935.

[0184] Embodiment 14

[0185] Preparation of 4-phenoxybenzonitrile

[0186] The specific reaction formula is as follows:

[0187]

[0188] The specific preparation process is as follows:

[0189] In an argon atmosphere, 4-nitrodiphenyl ether (32.5 mg, 0.10 mol, 1.0 equiv.) and 1.0 mL of acetonitrile were added to a reaction flask, followed by TMSCN (38 μL, 3.0 equiv.) and TBAF (0.4 mL, 4.0 equiv., 1.0 M in THF) to obtain a reaction mixture. The reaction mixture was then placed under 390 nm LEDs and stirred at room temperature for 48 hours. The mixture was then transferred to a flask containing ethyl acetate, and the volatiles were removed under vacuum to obtain a residue. The residue was purified by silica gel flash column chromatography using a hexane / ethyl acetate mixture as the eluent to obtain a colorless solid product, 4-phenoxybenzonitrile (18.9 mg, 62% yield).

[0190] On a silica gel thin layer plate using hexane-ethyl acetate as the developing solvent (the volume ratio of hexane to ethyl acetate was 30:1), the Rf of the product was measured to be 0.3.

[0191] The structural characterization data of the product are as follows:

[0192] 1 H NMR (400 MHz, CDCl3, 25 ℃, δ): 7.65 – 7.63 (m, 2H), 7.46 – 7.44(m, 2H), 7.30 – 7.28 (m, 1H), 7.06 – 7.04 (m, 4H) ppm.

[0193] 13 C NMR (100 MHz, CDCl3, 25 ℃, δ): 161.7, 154.8, 134.2, 130.3, 125.2,120.5, 118.9, 117.9, 105.8 ppm.

[0194] HRMS-EI(m / z) calc'd for C 13 HkDJ + [M+Na] + , 218.0576; found, 218.0577.

[0195] Embodiment 15

[0196] The preparation method of 1,1'-biphenyl-4-carbonitrile is basically the same as that of Example 2, except that the fluoride salt TBAF is replaced by NaF, and the yield of 1,1'-biphenyl-4-carbonitrile is 4%.

[0197] Example 16

[0198] The preparation method of 1,1'-biphenyl-4-carbonitrile is basically the same as that of Example 2, except that the fluoride salt TBAF is replaced by KF, and the yield of 1,1'-biphenyl-4-carbonitrile is 13%.

[0199] Embodiment 17

[0200] The preparation method of 1,1'-biphenyl-4-carbonitrile is basically the same as that of Example 2, except that the fluoride salt TBAF is replaced by CsF, and the yield of 1,1'-biphenyl-4-carbonitrile is 30%.

[0201] The above specific embodiments describe the implementation of the present invention in detail, but the present invention is not limited to the specific details in the above embodiments. Within the scope of the claims and technical concept of the present invention, the technical solution of the present invention can be modified and changed in many simple ways, and these simple modifications all belong to the protection scope of the present invention.

Claims

1. A method for preparing aromatic nitrile compounds by photoinduced denitration and cyanation of nitroaromatic hydrocarbons, characterized in that: include: Nitroaromatic hydrocarbon I, cyanation reagent, and fluoride salt are mixed in an organic solvent and reacted under light irradiation with a wavelength of 365 nm to 450 nm to obtain aromatic nitrile compound II. The specific reaction equation is as follows: ； In the formula, Ar is a substituted or unsubstituted aromatic group or a heteroaromatic group.

2. The method for preparing aromatic nitrile compounds by photoinduced denitration and cyanation of nitroaromatic hydrocarbons according to claim 1, characterized in that: The cyanation reagent is selected from one or more of TMSCN, acetone cyanohydrin, NaCN, Cu(CN)2 or CDAP.

3. The method for preparing aromatic nitrile compounds by photoinduced denitration and cyanation of nitroaromatic hydrocarbons according to claim 2, characterized in that: The cyanation reagent is TMSCN.

4. The method for preparing aromatic nitrile compounds by photoinduced denitration and cyanation of nitroaromatic hydrocarbons according to claim 1, characterized in that: The substituents of the substituted aromatic and heteroaromatic groups are selected from one or more of halogen, cyano, hydroxyl, trifluoromethyl, alkyl, alkoxy, aryloxy, acyloxy, ester, acyl, thienyl, oxazolyl, phenyl or amide.

5. The method for preparing aromatic nitrile compounds by photoinduced denitration and cyanation of nitroaromatic hydrocarbons according to claim 4, characterized in that: The substituent in the substituted aromatic group is phenyl.

6. The method for preparing aromatic nitrile compounds by photoinduced denitration and cyanation of nitroaromatic hydrocarbons according to claim 1, characterized in that: The aromatic group is selected from one of phenyl, styryl or condensed ring aromatic groups, and the heteroaromatic group is selected from one of furyl, pyridyl, benzopyridyl, pyrazole, benzoxazolyl, benzofuranyl, dibenzofuranyl, isoquinolyl or quinolyl.

7. The method for preparing aromatic nitrile compounds by photoinduced denitration and cyanation of nitroaromatic hydrocarbons according to claim 1, characterized in that: The nitroaromatic hydrocarbon is selected from one of the following structures: 。 8. The method for preparing aromatic nitrile compounds by photoinduced denitration and cyanation of nitroaromatic hydrocarbons according to claim 1, characterized in that: The fluoride salt is selected from one of TBAF, KF or CsF.

9. The method for preparing aromatic nitrile compounds by photoinduced denitration and cyanation of nitroaromatic hydrocarbons according to claim 1, characterized in that: The molar ratio of the nitroaromatic hydrocarbon, the cyanation reagent and the fluoride salt is 1:(0.8-3):(0.8-4).

10. The method for preparing aromatic nitrile compounds by photoinduced denitration and cyanation of nitroaromatic hydrocarbons according to claim 1, characterized in that: The reaction temperature is 25-55°C.

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