CN117447362A - Green synthesis method of azoxybenzene compound - Google Patents

Green synthesis method of azoxybenzene compound Download PDF

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Publication number
CN117447362A
CN117447362A CN202311383296.5A CN202311383296A CN117447362A CN 117447362 A CN117447362 A CN 117447362A CN 202311383296 A CN202311383296 A CN 202311383296A CN 117447362 A CN117447362 A CN 117447362A
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aromatic
catalyst
synthesis method
green synthesis
reaction
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李世云
赵薇
李兴存
王力
文彬
陈兴权
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Qingyuan Innovation Laboratory
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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C291/00—Compounds containing carbon and nitrogen and having functional groups not covered by groups C07C201/00 - C07C281/00
    • C07C291/02—Compounds containing carbon and nitrogen and having functional groups not covered by groups C07C201/00 - C07C281/00 containing nitrogen-oxide bonds
    • C07C291/08—Azoxy compounds
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
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Abstract

In an organic solvent, aromatic amine or aromatic hybrid amine is used as a raw material, and the aromatic amine is selectively oxidized into a corresponding azo oxide compound by a reaction system consisting of an oxidant and a catalyst; wherein the catalyst is NaOAc, sodium formate or KF, naF, csF, caF 2 、R″ 4 One or more of NF, wherein R' is one of alkyl, methyl, ethyl and butyl; compared with the metal catalyst in the prior art, the catalyst adopted by the invention has the advantages of low cost, high activity, good selectivity and small environmental pollution, and accords with the environment-friendly concept; meanwhile, the catalyst is less in dosage, the problems of catalyst recovery treatment and the like are not needed to be considered, and the operation steps are greatly simplified.

Description

Green synthesis method of azoxybenzene compound
Technical Field
The invention belongs to the field of synthesis of organic chemical raw materials and intermediates, and particularly relates to a green synthesis method for selectively catalyzing and oxidizing aromatic amine or aromatic hybrid amine into corresponding azoxybenzene compounds.
Background
The azoxybenzene compound has special 1, 3-dipole O-N=N bond, can be widely applied to the fields of medicines, dyes, resins, food additives, liquid crystal materials and the like, and has very broad market application prospect. Currently, azoxybenzene compounds are selectively prepared mainly through two paths of aromatic amino compound oxidation and aromatic nitro compound reduction, and the synthetic route is specifically shown in fig. 1; however, both processes require severe reaction conditions, and the selectivity of the target product is poor, which is challenging.
Typical reducing agents used in the reduction of aromatic nitro compounds include borohydride, hydrazine hydrate, alcohols and CO, such as: yufang Liu et al (molecular 2011,16,3563-3568) reduced several nitroaromatics to the corresponding azoxybenzenes in water using potassium borohydride under conditions of PEG-400 as a phase transfer catalyst. The method has simple experimental steps and high reaction efficiency. Ruiping Wei et al (Synth. Commun.2019,49:5, 688-696) developed a catalyst-free system for the reductive conversion of nitrobenzene to a variety of products. Nitrobenzene is used as a raw material, alcohol is used as a reducing agent, and KOH is utilized to promote the nitrobenzene to be selectively reduced into azoxybenzene and aniline. The method can complete selective conversion by only changing alcohols and changing temperature, and is simple to operate, economical and practical.
Hydrogen peroxide is commonly used as the oxidant in the oxidation process of aromatic amino compounds, and a few use oxygen or air as the oxidant. Such as: qin et al (Angew. Chem. Int. Ed.2022,61, e 202112907) developed a low cost, multifunctional Zr (OH) 4 Heterogeneous catalyst for use in H 2 O 2 Or O 2 The selective aniline oxide in the system is azoxybenzene. Song Yuwan et al (organic chemistry, 2019,39 (04): 1181-1186) report a method for improving the efficient, highly selective conversion of aniline to the corresponding azoxybenzene by adjusting the molar ratio of titanium silicon of TS-1. At a Si/Ti molar ratio of TS-1 of 80, H is used as 2 O 2 As an oxidizing agent, aryl anilines are converted in good yields and with high selectivity to the corresponding azoxybenzenes.
At present, a plurality of methods for synthesizing azoxybenzene are available, but the methods still need to be improved, for example, the requirements on equipment and other conditions in the synthesis process are high, a noble metal or a toxic catalyst is adopted in a reaction system, the environment is damaged, and some catalysts are difficult to recover, the required cost is high, and the application limitation is high. Therefore, the development of a green, efficient and safe way for obtaining the azoxybenzene product with high added value has important significance.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides a green synthesis method of an azoxybenzene compound.
The invention adopts the following technical scheme:
in an organic solvent, aromatic amine or aromatic hybrid amine is used as a raw material, and the aromatic amine is selectively oxidized into a corresponding azo oxide compound by a reaction system consisting of an oxidant and a catalyst;
wherein the catalyst is NaOAc, sodium formate or KF, naF, csF, caF 2 、R″ 4 One or more of NF, wherein R' is one of alkyl, methyl, ethyl and butyl.
Further, the molar amount of the catalyst is 0.1-3equiv of the aromatic amine or the aromatic hetero amine.
Further, the catalyst is NaF.
Further, the molar amount of the oxidizing agent is 3-20equiv of the aromatic amine or the aromatic hetero amine.
Further, the oxidizing agent is hydrogen peroxide.
Further, the mass concentration of the hydrogen peroxide is more than or equal to 30%.
Further, the R, R' is selected from hydrogen, halogen, -CF 3 、-OCF 3 、-CHF 2 -one or more of CN, ester group, alkyl, alkoxy, aryl; ar is an aromatic groupAromatic rings or heteroaromatic rings, the aromatic rings being selected from benzene rings or naphthalene rings, the heteroaromatic rings being selected from pyridine, thiophene, furan, pyridazine, pyrimidine, pyrazine, oxazole, isoxazole, thiazole, isothiazole, quinoline, benzothiazole or isoquinoline.
Further, the organic solvent is MeCN, DMF, DMSO, DCE, etOH, H 2 One or more of O.
Further, the reaction temperature is rt-100 ℃.
Further, the reaction time is 1h-36h.
As can be seen from the above description of the present invention, compared with the prior art, the present invention has the following beneficial effects:
firstly, the method takes aromatic amine or aromatic hybrid amine as raw material, and uses hydrogen peroxide as oxidant through screening catalyst and solvent, so as to realize the efficient and selective oxidation of the aromatic amine or aromatic hybrid amine into corresponding azoxybenzene compounds under mild conditions; the oxidant selected by the method is green, environment-friendly, pollution-free, the catalyst is common and easy to obtain, the price is low, the catalytic effect is obvious, the reaction condition is mild, the operation is simple, the cost is low, the rate is high, the selectivity is high, the product yield is high, and the method is a novel synthesis method of the azoxybenzene compound with good scientific research value and industrialization potential;
secondly, compared with the traditional metal catalyst, the catalyst adopted by the invention has the advantages of low cost, high activity, good selectivity and small environmental pollution, and accords with the environment-friendly concept; meanwhile, the catalyst consumption is small, the problems of catalyst recovery treatment and the like are not needed to be considered, and the operation steps are greatly simplified;
thirdly, the acetonitrile solvent adopted by the invention has excellent performance, simple post-reaction treatment, high-yield target product can be quickly obtained, and the whole catalytic system has strong universality, good scientific research value and great industrial application potential;
fourth, the oxidant adopted in the invention is hydrogen peroxide, and the byproduct after the reaction is only water, so that the method has no pollution, and has low requirements on reaction equipment and conditions, and compared with the traditional oxidant, the method has the advantages of greatly reduced cost and improved safety;
fifth, the raw material aromatic amine or aromatic hybrid amine adopted by the invention is used as industrial basic raw material, and is cheap and easy to obtain.
Drawings
FIG. 1 is a schematic diagram of the oxidation reaction mechanism of aromatic amino compounds and the reduction reaction mechanism of aromatic nitro compounds;
FIG. 2 is a synthetic route diagram of the azoxybenzene compound of the present invention;
FIG. 3 is a synthetic route diagram of example 1;
FIG. 4 is a synthetic route diagram of example 4;
FIG. 5 is a synthetic route diagram of example 5;
FIG. 6 is a synthetic route diagram of example 6;
FIG. 7 is a synthetic route diagram of example 7;
FIG. 8 is a synthetic route diagram of example 8;
FIG. 9 is a synthetic route diagram of example 9;
FIG. 10 is a synthetic route diagram of example 10;
FIG. 11 is a synthetic route diagram of example 11;
FIG. 12 is a synthetic route diagram of example 12;
FIG. 13 is a synthetic route diagram of example 13;
FIG. 14 is a synthetic route diagram of example 14;
FIG. 15 is a synthetic route diagram of example 15;
FIG. 16 is a synthetic route diagram of example 16;
FIG. 17 is a synthetic route diagram of example 17;
FIG. 18 is a synthetic route diagram of example 18;
FIG. 19 is a synthetic route diagram of example 19;
FIG. 20 is a synthetic route diagram of example 20;
FIG. 21 is a synthetic route diagram of example 21;
FIG. 22 is a synthetic route diagram of example 22;
FIG. 23 is a synthetic route diagram of example 23;
FIG. 24 is a synthetic route diagram of example 24;
FIG. 25 is a synthetic route diagram of example 25;
FIG. 26 is a synthetic route diagram of example 26;
FIG. 27 is a chart of hydrogen nuclear magnetic resonance spectra of example 1;
FIG. 28 is a chart of the hydrogen nuclear magnetic resonance spectrum of example 4.
Detailed Description
The invention is further described below by means of specific embodiments.
In an organic solvent, aromatic amine or aromatic hybrid amine is taken as a raw material, and the aromatic amine is selectively oxidized into a corresponding azoxybenzene compound by utilizing a reaction system consisting of an oxidant and a catalyst, wherein the synthetic route is shown in a figure 2; specifically, the reaction temperature is rt-100 ℃; the reaction time is 1h-36h.
Wherein R, R' is selected from hydrogen, halogen, -CF 3 、-OCF 3 、-CHF 2 -one or more of CN, ester group, alkyl, alkoxy, aryl; ar is an aromatic ring or an aromatic heterocyclic ring, wherein the aromatic ring is selected from benzene ring or naphthalene ring, and the aromatic heterocyclic ring is selected from pyridine, thiophene, furan, pyridazine, pyrimidine, pyrazine, oxazole, isoxazole, thiazole, isothiazole, quinoline, benzothiazole or isoquinoline.
The catalyst is NaOAc, sodium formate, KF, naF, csF, caF 2 、R″ 4 One or more of NF, wherein R' is one of alkyl, methyl, ethyl and butyl; specifically, the molar amount of the catalyst is 0.1-3equiv of the aromatic amine or the aromatic hetero amine.
The oxidant is hydrogen peroxide, and the mass concentration of the hydrogen peroxide is more than or equal to 30%; specifically, the molar amount of the oxidizing agent is 3-20equiv of the aromatic amine or the aromatic hetero amine.
The organic solvent is MeCN, DMF, DMSO, DCE, etOH, H 2 One or more of O.
The present invention will be further described in detail with reference to the following specific examples, but the content of the present invention is not limited thereto. The procedures, conditions, experimental methods, etc. for carrying out the present invention are common knowledge and common knowledge in the art, except for the following specific references, and the present invention is not particularly limited.
Example 1
See FIG. 3 for a synthetic route.
Aniline (2 mmol,186 mg) was dissolved in 4mL of acetonitrile, sodium fluoride (0.2 eq,17 mg) was added, and 2mL of 30% hydrogen peroxide was added to react at 80℃for 1h. After the completion of the reaction, the reaction mixture was poured into 10mL of water, extracted three times with methylene chloride, and the organic phase was concentrated and purified by silica gel column chromatography (gradient 0 to 5% PE: EA) to give a yellow oil in 91% yield.
The structural data are confirmed by nuclear magnetic resonance:
1H NMR(400MHz,Chloroform-d)δ8.34–8.29(m,2H),8.20–8.15(m,2H),7.60–7.46(m,5H),7.43–7.37(m,1H)。
comparative examples 1 to 6 were set for example 1, and the effect of the catalyst amount and the reaction time on the reaction was examined, and the catalytic results of aniline are shown in table 1, except that the catalyst amount and the reaction time were the same as those of example 1.
TABLE 1
As is clear from Table 1, when NaF was added in an amount of 0.2eq, the yield of the target product was 90% or more, and the reaction time was shortened as the yield of the product increased with increasing catalyst amount, so that the system was selectively charged with 2eq of catalyst.
Example 2
Aniline (2 mmol,186 mg) was dissolved in 4mL of DMF, sodium fluoride (2 eq,168 mg) was added, hydrogen peroxide 2mL was added, and the reaction was carried out at 80℃for 1h. The yield of the target product was 92% by GC monitoring.
For example 2, comparative examples 7-15 were set to examine the effect of different catalysts on the reaction, the catalyst amounts were all 4mmol, the remaining conditions were the same as in example 2, and the catalytic oxidation results of aniline are shown in Table 2.
TABLE 2
Example 3
Amplification reaction: aniline (53.7 mmol,5 g) was dissolved in 20mL acetonitrile, sodium fluoride (1 eq,2.25 g) was added, hydrogen peroxide (5 eq,27 mL) was slowly added dropwise to the reaction solution, and the reaction was carried out at 80 ℃ for 4 hours; the yield of the target product was 96% by GC monitoring. Namely, the reaction system has strong universality and can be used for large-scale industrial production.
Example 4
See FIG. 4 for synthetic routes.
Para-fluoroaniline (2 mmol,222 mg) was dissolved in 4mL of acetonitrile, sodium fluoride (4 mmol,168 mg) was added, and 2mL of hydrogen peroxide was added to react at 80℃for 2 hours. After the reaction, the reaction solution was concentrated, and the product was precipitated, washed with water three times, filtered, and the solid was dried to obtain 210mg of yellow powder with a yield of 96%.
The structural data are confirmed by nuclear magnetic resonance:
1H NMR(400MHz,Chloroform-d)δ8.35–8.29(m,2H),8.29–8.23(m,2H),7.22–7.13(m,4H).19F NMR(376MHz,Chloroform-d)δ-108.03(q,J＝6.3Hz),-108.59(q,J＝6.9Hz)。
example 5
See FIG. 5 for synthetic routes.
P-chloroaniline (2 mmol,254 mg) was dissolved in 4mL of acetonitrile, sodium fluoride (4 mmol,168 mg) was added, and 2mL of hydrogen peroxide was added to react at 80℃for 2 hours. After the completion of the reaction, the reaction mixture was poured into 10mL of water, extracted three times with methylene chloride, and the organic phase was concentrated and purified by silica gel column chromatography (gradient 0 to 5% PE: EA) to give 260mg of a yellow solid with a yield of 98%.
The structural data are confirmed by nuclear magnetic resonance:
1H NMR(400MHz,Chloroform-d)δ8.28–8.23(m,2H),8.19–8.13(m,2H),7.51–7.42(m,4H)。
example 6
See FIG. 6 for synthetic routes.
Para-methoxyaniline (2 mmol,246 mg) was dissolved in 4mL of acetonitrile, sodium fluoride (4 mmol,168 mg) was added, and 2mL of hydrogen peroxide was added to react at 80℃for 2h. After the completion of the reaction, the reaction mixture was poured into 10mL of water, extracted three times with methylene chloride, and the organic phase was concentrated and purified by silica gel column chromatography (gradient 0 to 5% PE: EA) to give 253mg of a yellow solid in 98% yield.
The structural data are confirmed by nuclear magnetic resonance:
1 H NMR(400MHz,Chloroform-d)δ8.31–8.18(m,4H),7.00–6.93(m,4H),3.92–3.86(m,6H)。
example 7
See FIG. 7 for synthetic routes.
Para-tert-butylaniline (2 mmol,298 mg) was dissolved in 4mL of acetonitrile, sodium fluoride (4 mmol,168 mg) was added, and 2mL of hydrogen peroxide was added to react at 80℃for 2 hours. After the completion of the reaction, the reaction mixture was poured into 10mL of water, extracted three times with methylene chloride, and the organic phase was concentrated and purified by silica gel column chromatography (gradient 0 to 5% PE: EA) to give 285mg of yellow crystals in 92% yield.
The structural data are confirmed by nuclear magnetic resonance:
1 H NMR(400MHz,Chloroform-d)δ8.23–8.18(m,2H),8.17–8.12(m,2H),7.53–7.48(m,4H),1.37(d,J＝2.9Hz,18H)。
example 8
See FIG. 8 for synthetic routes.
Para-trifluoromethoxy aniline (2 mmol,354 mg) was dissolved in 4mL of acetonitrile, sodium fluoride (4 mmol,168 mg) was added, and 2mL of hydrogen peroxide was added to react at 80℃for 3h. After the completion of the reaction, the reaction mixture was poured into 10mL of water, extracted three times with methylene chloride, and the organic phase was concentrated and purified by silica gel column chromatography (gradient 0 to 5% PE: EA) to give 348mg of white crystals with a yield of 95%.
The structural data are confirmed by nuclear magnetic resonance:
1H NMR(400MHz,Chloroform-d)δ8.40–8.34(m,2H),8.28–8.22(m,2H),7.34(dd,J＝12.5,8.7Hz,4H).19F NMR(376MHz,Chloroform-d)δ-57.69,-57.79。
example 9
See FIG. 9 for synthetic routes.
4-alkynylaniline (2 mmol,234 mg) was dissolved in 4mL of acetonitrile, sodium fluoride (4 mmol,168 mg) was added, and 2mL of hydrogen peroxide was added to react at 80℃for 2 hours. After the reaction, the reaction solution was concentrated to precipitate a solid, which was rinsed three times with water, filtered, and the solid was dried to give a yellow solid with a yield of 96%.
The structural data are confirmed by nuclear magnetic resonance:
1H NMR(400MHz,Chloroform-d)δ8.31–8.24(m,1H),8.18–8.13(m,1H),7.65–7.56(m,2H),3.27(s,1H),3.21(s,0H)。
example 10
See FIG. 10 for synthetic routes.
O-fluoroaniline (2 mmol,222 mg) was dissolved in 4mL of acetonitrile, sodium fluoride (4 mmol,168 mg) was added, and 2mL of hydrogen peroxide was added to react at 80℃for 12 hours. After the completion of the reaction, the reaction mixture was poured into 10mL of water, extracted three times with methylene chloride, and the organic phase was concentrated and purified by silica gel column chromatography (gradient 0 to 5% PE: EA) to give 166mg of a yellow solid in 71% yield.
The structural data are confirmed by nuclear magnetic resonance:
1H NMR(400MHz,Chloroform-d)δ8.25–8.19(m,1H),7.86(td,J＝7.9,1.8Hz,1H),7.44(tdd,J＝8.1,4.6,1.7Hz,1H),7.34–7.28(m,1H),7.24–7.12(m,4H).19F NMR(376MHz,Chloroform-d)δ-115.92(dt,J＝11.9,6.1Hz),-120.70(dt,J＝11.4,5.4Hz)。
example 11
See FIG. 11 for synthetic routes.
O-chloroaniline (2 mmol,254 mg) was dissolved in 4mL of acetonitrile, sodium fluoride (4 mmol,168 mg) was added, and 2mL of hydrogen peroxide was added to react at 80℃for 12 hours. After the completion of the reaction, the reaction mixture was poured into 10mL of water, extracted three times with methylene chloride, and the organic phase was concentrated and purified by silica gel column chromatography (gradient 0 to 5% PE: EA) to give 215mg of a yellow solid in 81% yield.
The structural data are confirmed by nuclear magnetic resonance:
1H NMR(400MHz,Chloroform-d)δ8.01(dd,J＝8.0,1.7Hz,1H),7.76(dd,J＝7.5,2.1Hz,1H),7.57–7.51(m,2H),7.48–7.42(m,2H),7.39(td,J＝7.7,1.4Hz,1H),7.31(td,J＝7.7,1.7Hz,1H)。
example 12
See FIG. 12 for synthetic routes.
O-methylaniline (2 mmol,214 mg) was dissolved in 4mL of acetonitrile, sodium fluoride (4 mmol,168 mg) was added, and 2mL of hydrogen peroxide was added to react at 80℃for 12 hours. After the completion of the reaction, the reaction mixture was poured into 10mL of water, extracted three times with methylene chloride, and the organic phase was concentrated and purified by silica gel column chromatography (gradient 0 to 5% PE: EA) to give 199mg of a yellow solid with a yield of 88%.
The structural data are confirmed by nuclear magnetic resonance:
1H NMR(400MHz,Chloroform-d)δ8.03(dd,J＝7.5,2.3Hz,1H),7.68(dd,J＝8.1,1.5Hz,1H),7.42–7.37(m,1H),7.35–7.30(m,4H),7.29–7.27(m,1H),2.53(s,3H),2.38(s,3H)。
example 13
See FIG. 13 for synthetic routes.
2, 6-difluoroaniline (2 mmol,258 mg) was dissolved in 4mL of acetonitrile, sodium fluoride (4 mmol,168 mg) was added, and 2mL of hydrogen peroxide was added to react at 80℃for 12h. After the completion of the reaction, the reaction mixture was poured into 10mL of water, extracted three times with methylene chloride, and the organic phase was concentrated and purified by silica gel column chromatography (gradient 0 to 5% PE: EA) to give 227mg of a yellow solid with a yield of 84%.
The structural data are confirmed by nuclear magnetic resonance:
1H NMR(400MHz,Chloroform-d)δ7.48(tt,J＝8.6,5.9Hz,1H),7.33(tt,J＝8.5,6.0Hz,1H),7.12(t,J＝8.0Hz,2H),7.04(t,J＝8.4Hz,2H).19F NMR(376MHz,Chloroform-d)δ-113.50(t,J＝7.3Hz),-120.53(t,J＝7.3Hz)。
example 14
See FIG. 14 for synthetic routes.
Methylaniline (2 mmol,214 mg) was dissolved in 4mL of acetonitrile, sodium fluoride (4 mmol,168 mg) was added, hydrogen peroxide 2mL was added, and the mixture was reacted at 80℃for 12 hours. After the completion of the reaction, the reaction mixture was poured into 10mL of water, extracted three times with methylene chloride, and the organic phase was concentrated and purified by silica gel column chromatography (gradient 0 to 5% PE: EA) to give 219mg of a yellow oil in 97% yield.
The structural data are confirmed by nuclear magnetic resonance:
1H NMR(400MHz,Chloroform-d)δ8.24(dd,J＝13.3,2.3Hz,1H),8.10–8.04(m,2H),7.99(ddd,J＝9.0,2.4,1.5Hz,1H),7.02(td,J＝8.9,2.0Hz,2H),3.97(d,J＝3.9Hz,6H)。
example 15
See FIG. 15 for synthetic routes.
M-trifluoromethylaniline (2 mmol,322 mg) was dissolved in 4mL of acetonitrile, sodium fluoride (4 mmol,168 mg) was added, and 2mL of hydrogen peroxide was added to react at 80℃for 1.5h. After the completion of the reaction, the reaction mixture was poured into 10mL of water, extracted three times with methylene chloride, and the organic phase was concentrated and purified by silica gel column chromatography (gradient 0 to 5% PE: EA) to give 311mg of a yellowish green solid in 93% yield.
The structural data are confirmed by nuclear magnetic resonance:
1H NMR(400MHz,Chloroform-d)δ8.63(s,1H),8.54(d,J＝8.3Hz,1H),8.48(s,1H),8.38(d,J＝7.8Hz,1H),7.87(d,J＝7.7Hz,1H),7.67(dt,J＝24.7,8.1Hz,3H).19F NMR(376MHz,Chloroform-d)δ-62.69,-62.74。
example 16
See FIG. 16 for synthetic routes.
2, 4-difluoroaniline (2 mmol,258 mg) was dissolved in 4mL of acetonitrile, sodium fluoride (4 mmol,168 mg) was added, and 2mL of hydrogen peroxide was added to react at 80℃for 5h. After the reaction was completed, the reaction solution was concentrated, rinsed three times with water, filtered, and the solid was dried to give 248mg of yellow solid with a yield of 92%.
The structural data are confirmed by nuclear magnetic resonance:
1H NMR(400MHz,Chloroform-d)δ8.61–8.52(m,1H),8.02–7.93(m,1H),7.06–6.93(m,4H).19F NMR(376MHz,Chloroform-d)δ-103.46,-105.16,-110.83,-114.45。
example 17
See FIG. 17 for synthetic routes.
2, 5-difluoroaniline (2 mmol,258 mg) was dissolved in 4mL of acetonitrile, sodium fluoride (4 mmol,168 mg) was added, and 2mL of hydrogen peroxide was added to react at 80℃for 12h. After the completion of the reaction, the reaction mixture was poured into 10mL of water, extracted three times with methylene chloride, and the organic phase was concentrated and purified by silica gel column chromatography (gradient 0 to 5% PE: EA) to give 251mg of a yellow solid with a yield of 93%.
The structural data are confirmed by nuclear magnetic resonance: 1H NMR (400 MHz, chloroform-d) delta 8.25-8.18 (m, 1H), 7.72-7.66 (m, 1H), 7.31-7.26 (m, 1H), 7.24 (dd, J=4.4, 1.9Hz, 1H), 7.19 (td, J=9.4, 4.8Hz, 1H), 7.15-7.08 (m, 1H).
Example 18
See FIG. 18 for synthetic routes.
3, 5-difluoroaniline (2 mmol,258 mg) was dissolved in 4mL acetonitrile, sodium fluoride (4 mmol,168 mg) was added, hydrogen peroxide 2mL was added, and the reaction was carried out at 80℃for 13h. After the completion of the reaction, the reaction mixture was poured into 10mL of water, extracted three times with methylene chloride, and the organic phase was concentrated and purified by silica gel column chromatography (gradient 0 to 5% PE: EA) to give 259mg of yellow solid in 96% yield.
The structural data are confirmed by nuclear magnetic resonance: 1H NMR (400 MHz, chloroform-d) delta 7.91-7.84 (m, 2H), 7.79-7.72 (m, 2H), 7.07 (tt, J=8.2, 2.4Hz, 1H), 6.91 (tt, J=8.5, 2.4Hz, 1H) 19F NMR (376MHz, chloroform-d) delta-106.55 (t, J=7.6 Hz), -108.67 (t, J=8.2 Hz).
Example 19
See FIG. 19 for the synthetic route.
3, 4-difluoroaniline (2 mmol,258 mg) was dissolved in 4mL acetonitrile, sodium fluoride (4 mmol,168 mg) was added, hydrogen peroxide 2mL was added, and the reaction was carried out at 80℃for 8h. After the completion of the reaction, the reaction mixture was poured into 10mL of water, extracted three times with methylene chloride, and the organic phase was concentrated and purified by silica gel column chromatography (gradient 0 to 5% PE: EA) to give 262mg of a yellow solid with a yield of 97%.
The structural data are confirmed by nuclear magnetic resonance:
1H NMR(400MHz,Chloroform-d)δ8.33(ddd,J＝12.2,7.7,2.4Hz,1H),8.22–8.16(m,1H),8.14–8.09(m,1H),7.89(ddt,J＝8.7,4.3,2.1Hz,1H),7.36–7.23(m,2H).19F NMR(376MHz,Chloroform-d)δ-131.16(dt,J＝20.7,10.4Hz),-131.77–-131.98(m),-133.85(dt,J＝19.5,9.2Hz),-135.17(dt,J＝20.9,10.5Hz)。
example 20
See FIG. 20 for synthetic routes.
3-methoxy-4-fluoroaniline (2 mmol,282 mg) was dissolved in 4mL of acetonitrile, sodium fluoride (4 mmol,168 mg) was added, and 2mL of hydrogen peroxide was added to react at 80℃for 10 hours. After the reaction, the reaction solution was concentrated to precipitate a solid, and the solid was suction-filtered, rinsed three times with water, and the filter cake was dried to obtain 288mg of yellow solid with a yield of 98%.
The structural data are confirmed by nuclear magnetic resonance:
1H NMR(400MHz,Chloroform-d)δ8.06(dd,J＝8.3,2.3Hz,1H),7.95(dd,J＝7.6,2.6Hz,1H),7.92–7.88(m,1H),7.79(ddd,J＝8.9,4.4,2.4Hz,1H),7.18(ddd,J＝10.7,8.8,3.4Hz,2H),4.00(s,3H),3.96(s,3H).19F NMR(376MHz,Chloroform-d)δ-129.34(t,J＝10.3Hz),-129.55(dd,J＝14.3,8.4Hz)。
example 21
See FIG. 21 for synthetic routes.
3-chloro-4-fluoroaniline (2 mmol,290 mg) was dissolved in 4mL of acetonitrile, sodium fluoride (4 mmol,168 mg) was added, and 2mL of hydrogen peroxide was added to react at 80℃for 2 hours. After the reaction, the reaction solution was concentrated to precipitate a solid, and the solid was filtered, rinsed three times with water, and the cake was dried to obtain 296mg of a white solid with a yield of 98%.
The structural data are confirmed by nuclear magnetic resonance:
1H NMR(400MHz,Chloroform-d)δ8.47(dd,J＝7.2,2.4Hz,1H),8.42(dd,J＝6.5,2.7Hz,1H),8.23(ddd,J＝9.0,4.2,2.7Hz,1H),8.08(ddd,J＝9.0,4.6,2.4Hz,1H),7.31–7.26(m,1H),7.24(d,J＝8.8Hz,1H).19F NMR(376MHz,Chloroform-d)δ-109.32,-110.21。
example 22
See FIG. 22 for synthetic routes.
2-fluoro-4-chloroaniline (2 mmol,290 mg) was dissolved in 4mL of acetonitrile, sodium fluoride (4 mmol,168 mg) was added, and 2mL of hydrogen peroxide was added to react at 80℃for 14h. After the completion of the reaction, the reaction mixture was poured into 10mL of water, extracted three times with methylene chloride, and the organic phase was concentrated and purified by silica gel column chromatography (gradient 0 to 5% PE: EA) to give 260mg of a yellow solid in 86% yield.
The structural data are confirmed by nuclear magnetic resonance:
1H NMR(400MHz,Chloroform-d)δ8.43(dd,J＝9.1,7.9Hz,1H),7.95–7.88(m,1H),7.34–7.26(m,2H),7.25–7.20(m,2H).19F NMR(376MHz,Chloroform-d)δ-112.98(t,J＝9.0Hz),-116.67(t,J＝8.9Hz)。
example 23
See FIG. 23 for synthetic routes.
3-fluoro-4-methoxyaniline (2 mmol,282 mg) was dissolved in 4mL of acetonitrile, sodium fluoride (4 mmol,168 mg) was added, and 2mL of hydrogen peroxide was added to react at 80℃for 12h. After the reaction, the reaction solution was concentrated to precipitate a solid, and the solid was filtered, rinsed three times with water, and the cake was dried to give 276mg of a yellow solid with a yield of 94%.
The structural data are confirmed by nuclear magnetic resonance:
1H NMR(400MHz,Chloroform-d)δ8.24(dd,J＝13.3,2.3Hz,1H),8.11–8.04(m,2H),7.99(ddt,J＝8.9,2.5,1.5Hz,1H),7.02(td,J＝8.9,1.6Hz,2H),3.97(d,J＝3.8Hz,6H).19F NMR(376MHz,Chloroform-d)δ-132.53(t,J＝9.8Hz),-133.55(dd,J＝13.4,9.1Hz)。
example 24
See FIG. 24 for synthetic routes.
2, 5-dimethylaniline (2 mmol,242 mg) was dissolved in 4mL of acetonitrile, sodium fluoride (4 mmol,168 mg) was added, and 2mL of hydrogen peroxide was added to react at 80℃for 8 hours. After the completion of the reaction, the reaction mixture was poured into 10mL of water, extracted three times with methylene chloride, and the organic phase was concentrated and purified by silica gel column chromatography (gradient 0 to 5% PE: EA) to give 199mg of a yellow solid with a yield of 88%.
The structural data are confirmed by nuclear magnetic resonance:
1H NMR(400MHz,Chloroform-d)δ7.75(s,1H),7.47(s,1H),7.22–7.17(m,3H),7.07(d,J＝9.8Hz,1H),2.47(s,3H),2.39(d,J＝5.6Hz,6H),2.31(s,3H).
example 25
See FIG. 25 for synthetic routes.
3-chloro-4-methylaniline (2 mmol,282 mg) was dissolved in 4mL of acetonitrile, sodium fluoride (4 mmol,168 mg) was added, and 2mL of hydrogen peroxide was added to react at 80℃for 4h. After the reaction was completed, the reaction solution was concentrated to precipitate a solid, and the solid was filtered and rinsed three times with water, and dried to give 282mg of a yellow solid with a yield of 96%.
The structural data are confirmed by nuclear magnetic resonance:
1H NMR(400MHz,Chloroform-d)δ8.33–8.29(m,2H),8.09(dd,J＝8.3,2.3Hz,1H),7.97(dd,J＝8.3,2.0Hz,1H),7.35(dd,J＝10.5,7.9Hz,2H),2.47(s,3H),2.44(s,3H)。
example 26
See FIG. 26 for synthetic routes.
3-aminopyridine (2 mmol,188 mg) was dissolved in 4mL of acetonitrile, sodium fluoride (4 mmol,168 mg) was added, hydrogen peroxide 2mL was added, and the mixture was reacted at 80℃for 12h. After the completion of the reaction, the reaction mixture was poured into 10mL of water, extracted three times with methylene chloride, and the organic phase was concentrated and purified by silica gel column chromatography (gradient 0 to 5% PE: EA) to give 196mg of a white solid with a yield of 98%.
The structural data are confirmed by nuclear magnetic resonance:
1H NMR(400MHz,Chloroform-d)δ9.58(d,J＝2.5Hz,1H),9.27(d,J＝2.3Hz,1H),8.84(dd,J＝4.8,1.5Hz,1H),8.79(ddd,J＝8.3,2.4,1.5Hz,1H),8.64(dd,J＝4.9,1.5Hz,1H),8.61(ddd,J＝8.4,2.6,1.5Hz,1H),7.50(dddd,J＝14.3,8.4,4.8,0.7Hz,2H)。
according to the invention, aromatic amine or aromatic hybrid amine is used as a raw material, and through screening a catalyst and a solvent, hydrogen peroxide is used as an oxidant, and the efficient and selective oxidation of the aromatic amine or aromatic hybrid amine into corresponding azoxybenzene compounds is realized under mild conditions; the oxidant selected by the method is green and environment-friendly, has no pollution, the catalyst is common and easy to obtain, the price is low, the catalytic effect is obvious, the reaction condition is mild, the operation is simple, the cost is low, the rate is high, the selectivity is high, the product yield is high, and the method is a novel synthesis method of the azoxybenzene compound with good scientific research value and industrialization potential.
The foregoing description is only illustrative of the preferred embodiments of the present invention and is not to be construed as limiting the scope of the invention, i.e., the invention is not to be limited to the details of the claims and the description, but rather is to cover all modifications which are within the scope of the invention.

Claims (10)

1. A green synthesis method of an azoxybenzene compound is characterized in that: in an organic solvent, aromatic amine or aromatic hybrid amine is taken as a raw material, and the aromatic amine is selectively oxidized into a corresponding azo oxide compound by utilizing a reaction system consisting of an oxidant and a catalyst, wherein the synthetic route is as follows:
wherein the catalyst is NaOAc, sodium formate or KF, naF, csF, caF 2 、R″ 4 One or more of NF, wherein R' is one of alkyl, methyl, ethyl and butyl.
2. The green synthesis method of the azoxybenzene compound according to claim 1, which is characterized in that: the molar amount of the catalyst is 0.1-3equiv of aromatic amine or aromatic hetero amine.
3. The green synthesis method of the azoxybenzene compound according to claim 1, which is characterized in that: the catalyst is NaF.
4. The green synthesis method of the azoxybenzene compound according to claim 1, which is characterized in that: the molar amount of the oxidant is 3-20equiv of aromatic amine or aromatic hetero amine.
5. The green synthesis method of the azoxybenzene compound according to claim 1, which is characterized in that: the oxidizing agent is hydrogen peroxide.
6. The green synthesis method of the azoxybenzene compound according to claim 5, wherein the method comprises the following steps: the mass concentration of the hydrogen peroxide is more than or equal to 30 percent.
7. The green synthesis method of the azoxybenzene compound according to claim 1, which is characterized in that: the R, R' is selected from hydrogen, halogen, -CF 3 、-OCF 3 、-CHF 2 -one or more of CN, ester group, alkyl, alkoxy, aryl; ar is an aromatic ring or an aromatic heterocyclic ring, wherein the aromatic ring is selected from benzene ring or naphthalene ring, and the aromatic heterocyclic ring is selected from pyridine, thiophene, furan, pyridazine, pyrimidine, pyrazine, oxazole, isoxazole, thiazole, isothiazole, quinoline, benzothiazole or isoquinoline.
8. The green synthesis method of the azoxybenzene compound according to claim 1, which is characterized in that: the organic solvent is MeCN, DMF, DMSO, DCE, etOH, H 2 One or more of O.
9. The green synthesis method of the azoxybenzene compound according to claim 1, which is characterized in that: the reaction temperature is rt-100 ℃.
10. The green synthesis method of the azoxybenzene compound according to claim 1, which is characterized in that: the reaction time is 1h-36h.
CN202311383296.5A 2023-10-24 2023-10-24 Green synthesis method of azoxybenzene compound Pending CN117447362A (en)

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