Photochemical synthesis method of azotriazole compound

Abstract

The invention discloses a photochemical synthesis method of an azotriazole compound. The photochemical synthesis method comprises the following steps: S1, adding a catalyst and a solvent into a reactor, and stirring; s2, adding an amino triazole compound and an inorganic base, and carrying out ultrasonic treatment until the amino triazole compound and the inorganic base are completely dissolved to obtain a reaction solution; s3, putting the reaction solution into a photoreactor, stirring and illuminating, and obtaining a mixed solution after the reaction is completed; s4, concentrating the mixed solution under vacuum, adding ultrapure water, centrifuging and filtering to obtain filter residues and filtrate; s5, adjusting the pH value of the filtrate to be neutral, standing overnight, filtering, washing and drying to obtain an azotriazole compound; compared with a traditional thermal chemical synthesis method, the photocatalytic synthesis method of the azotriazole compound has the advantages that the use of harmful solvents and reagents is reduced, the production cost is reduced, and the reaction safety and controllability are also improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of organic synthesis, and particularly relates to a photochemical synthesis method of azotriazole compounds. Background Art

[0002] Azotriazole compounds are a class of organic compounds with unique chemical properties. Their molecular structure contains one or more azo groups (-N=N-) and an electron-deficient ring, which enables azotriazole compounds to play a crucial role in the fields of biochemistry and materials science. The traditional synthesis of azotriazole compounds mainly relies on thermochemical synthesis, such as oxidation condensation method, cycloaddition method, etc. The oxidation condensation method usually uses oxidants such as potassium permanganate or sodium nitrite to promote the reaction. Although this method can effectively generate the target product, it requires high temperature and high pressure conditions and will produce a large amount of wastewater and other pollutants. The cycloaddition method uses strong acids or strong bases as catalysts to form azotriazole compounds through intermolecular cycloaddition reactions. However, this method often has low yields, complex operations, and may produce environmentally harmful by-products.

[0003] The traditional thermochemical synthesis methods of azotriazole compounds all have problems such as environmental pollution caused by reagents, high temperature and high pressure required for reactions, complex operations, high economic costs, and low yields. Therefore, there is an urgent need to develop a more environmentally friendly and sustainable synthesis route for azotriazole compounds. Based on this, researchers have explored the use of photochemical synthesis methods to prepare azotriazole compounds to reduce the use of harmful chemicals and improve atom economy. For example, the photocatalytic synthesis method of aromatic azo compounds has been widely reported (Chinese Patent CN201811192062.1). In addition, the photochemical and electrochemical syntheses of certain polyazacyclic azo compounds have also been reported.

[0004] However, compared with the extensive research on electron-rich systems, the photocatalytic azo coupling reaction of electron-deficient systems is still a relatively unexplored field. In particular, the photocatalytic azo coupling reaction of aminotriazole compounds has not been reported so far. Therefore, there is an urgent need to develop a photochemical synthesis method for aminotriazole compounds. Summary of the Invention

[0005] The purpose of the present invention is to provide a photochemical synthesis method of azotriazole compounds to solve the problem that the photochemical synthesis method of the above-mentioned aminotriazole compounds is not perfect enough.

[0006] To achieve the above purpose, the present invention provides a photochemical synthesis method of azotriazole compounds, including the following steps:

[0007] S1: Add a catalyst and a solvent into a reactor and stir.

[0008] S2: Then add the aminotriazole compound and inorganic base, and perform ultrasonic treatment until completely dissolved to obtain a reaction solution; the chemical general formula of the aminotriazole compound is:

[0009]

[0010] S3: Place the reaction solution in a photoreactor, stir and irradiate with light. After the reaction is completed, a mixed solution is obtained;

[0011] S4: Concentrate the mixed solution under vacuum, add ultrapure water, centrifuge and filter to obtain a filter residue and a filtrate;

[0012] S5: Adjust the pH value of the filtrate to neutral, let it stand overnight, filter, wash and dry to obtain the azotriazole compound.

[0013] The reaction equation of the present invention is as follows:

[0014]

[0015] Preferably, in step S1, the catalyst is an Ir catalyst, and the Ir catalyst is (Ir[dF(CF3)ppy]2(dtbpy))PF6, and the solvent is methanol. The solvent used in the present invention is not limited to methanol, and other organic solvents can also be used to prepare the product of the present invention.

[0016] Preferably, in step S1, the addition amount of the catalyst is 0.5 - 1.5 mol% of the aminotriazole compound, and the ratio of the aminotriazole compound to the solvent is 1 mmol: 8 - 20 mL.

[0017] Preferably, in step S2, R is H, -CH3, -CH2CH3, -iPr, -nPr, cyclopropyl, -Ph, -Cl, -Br, -CF3 or -OCH3.

[0018] Preferably, in step S2, the inorganic base is at least one of sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium carbonate, and potassium carbonate.

[0019] Preferably, in step S2, the molar ratio of the aminotriazole compound to the inorganic base is 1: 1 - 3.

[0020] Preferably, in step S3, the conditions of light irradiation are: irradiate with an LED, the power is 1 - 15 W, and the wavelength is 350 - 700 nm.

[0021] Preferably, in step S3, the conditions of light irradiation are: irradiate with an LED, the power is 15 W, and the wavelength is 450 nm.

[0022] Preferably, in step S3, the light irradiation time is 20 - 30 h.

[0023] Preferably, in step S4, the volume ratio of the solvent to the ultrapure water is 1:1 to 2.

[0024] Therefore, the present invention adopts the above-mentioned photochemical synthesis method of azotriazole compounds, and has the following beneficial effects:

[0025] (1) Compared with the traditional thermochemical synthesis method, the photocatalytic synthesis method of the present invention not only reduces the use of harmful solvents and reagents, lowers the production cost, but also improves the safety and controllability of the reaction.

[0026] (2) The synthesis method of the present invention significantly improves the atom economy and reduces waste generation, which conforms to the principles of green chemistry.

[0027] (3) The present invention not only opens up a new way for the synthesis of azotriazole compounds, but also provides a reference for the application of photocatalytic technology in other complex organic synthesis reactions.

[0028] The technical solution of the present invention will be further described in detail below through examples and drawings. Description of the Drawings

[0029] Figure 1 is the 1H NMR spectrum of product 2a;

[0030] Figure 2 is the 13C NMR spectrum of product 2a;

[0031] Figure 3 is the 1H NMR spectrum of product 2b;

[0032] Figure 4 is the 13C NMR spectrum of product 2b;

[0033] Figure 5 is the 1H NMR spectrum of product 2c;

[0034] Figure 6 is the 13C NMR spectrum of product 2c;

[0035] Figure 7 is the 1H NMR spectrum of product 2d;

[0036] Figure 8 is the 13C NMR spectrum of product 2d;

[0037] Figure 9 is the 1H NMR spectrum of product 2e;

[0038] Figure 10 is the 13C NMR spectrum of product 2e;

[0039] Figure 11 is the 1H NMR spectrum of product 2f;

[0040] Figure 12 13C NMR spectrum of product 2f;

[0041] Figure 13 1H NMR spectrum of product 2g;

[0042] Figure 14 13C NMR spectrum of product 2g;

[0043] Figure 15 13C NMR spectrum of product 2h;

[0044] Figure 16 13C NMR spectrum of product 2i;

[0045] Figure 17 13C NMR spectrum of product 2j;

[0046] Figure 18 1H NMR spectrum of product 2k;

[0047] Figure 19 13C NMR spectrum of product 2k. Detailed implementation mode

[0048] The present invention will be further described below. It should be noted that this embodiment is based on the present technical solution and gives detailed implementation methods and specific operation processes, but the present invention is not limited to this embodiment.

[0049] The raw materials used in the following examples were all purchased directly.

[0050] Example 1

[0051] A photochemical synthesis method of azotriazole compounds, comprising the following steps:

[0052] S1: Add the catalyst (Ir[dF(CF3)ppy]2(dtbpy))PF6 into a quartz tube containing a magnetic stir bar and 10 mL of methanol; the addition amount of the catalyst is 1 mol% of the aminotriazole compound 1a.

[0053] S2: Then add 1 mmol of the aminotriazole compound 1a and 2 mmol of sodium hydroxide, and perform ultrasonic treatment until completely dissolved to obtain a reaction solution.

[0054] The chemical structural formula of the aminotriazole compound is:

[0055]

[0056] S3: Place the reaction solution in a photoreactor, stir at room temperature, and irradiate with a 15 W, 450 nm LED lamp for 24 h. After the reaction is completed, a mixed solution is obtained.

[0057] S4: Concentrate the mixture under vacuum, add 10 mL of ultrapure water, centrifuge and filter to obtain the filter residue and the filtrate; the main component of the filter residue is the catalyst, which can be recycled in this step. Repeated experimental results show that the recycled catalyst can be used for photocatalytic reactions, and the conversion rate of the raw material exceeds 90%.

[0058] S5: Adjust the pH value of the filtrate to neutral, let it stand overnight, filter, wash and dry to obtain the azotriazole compound 2a.

[0059] The reaction equation of Example 1 is:

[0060]

[0061] Example 2

[0062] The difference between this example and Example 1 is that the aminotriazole compound is different. The chemical structural formula of the aminotriazole compound 1b in this example is:

[0063]

[0064] The reaction equation of Example 2 is:

[0065]

[0066] Example 3

[0067] The difference between this example and Example 1 is that the aminotriazole compound is different. The chemical structural formula of the aminotriazole compound 1c in this example is:

[0068]

[0069] The reaction equation of Example 3 is:

[0070]

[0071] Example 4

[0072] The difference between this example and Example 1 is that the aminotriazole compound is different. The chemical structural formula of the aminotriazole compound 1d in this example is:

[0073]

[0074] The reaction equation of Example 4 is:

[0075]

[0076] Example 5

[0077] The difference between this example and Example 1 is that the aminotriazole compounds are different. The chemical structural formula of the aminotriazole compound 1e in this example is:

[0078]

[0079] The reaction equation of Example 5 is:

[0080]

[0081] Example 6

[0082] The difference between this example and Example 1 is that the aminotriazole compounds are different. The chemical structural formula of the aminotriazole compound 1f in this example is:

[0083]

[0084] The reaction equation of Example 6 is:

[0085]

[0086] Example 7

[0087] The difference between this example and Example 1 is that the aminotriazole compounds are different. The chemical structural formula of the aminotriazole compound 1g in this example is:

[0088]

[0089] The reaction equation of Example 7 is:

[0090]

[0091] Example 8

[0092] The difference between this example and Example 1 is that the aminotriazole compounds are different. The chemical structural formula of the aminotriazole compound 1h in this example is:

[0093]

[0094] The reaction equation of Example 8 is:

[0095]

[0096] Example 9

[0097] The difference between this example and Example 1 is that the aminotriazole compounds are different. The chemical structural formula of the aminotriazole compound 1i in this example is:

[0098]

[0099] The reaction equation of Example 9 is:

[0100]

[0101] Example 10

[0102] The difference between this example and Example 1 is that the aminotriazole compound is different. The chemical structural formula of the aminotriazole compound 1j in this example is:

[0103]

[0104] The reaction equation of Example 10 is:

[0105]

[0106] Example 11

[0107] The difference between this example and Example 1 is that the aminotriazole compound is different. The chemical structural formula of the aminotriazole compound 1k in this example is:

[0108]

[0109] The reaction equation of Example 11 is:

[0110]

[0111] The catalysts and the raw material aminotriazole compounds 1a - 1k used in Examples 1 to 11 were all directly purchased, and the corresponding products azotriazole compounds 2a - 2k were obtained. The proton nuclear magnetic resonance spectra and carbon nuclear magnetic resonance spectra of the products azotriazole compounds 2a - 2k are shown in Figures 1 to 19 , and the above products were all successfully synthesized.

[0112] The chemical structural formulas and the yields of the products of Examples 1 to 11 are as follows:

[0113]

[0114] As can be seen from the above, after optimizing the reaction conditions in Example 1, Examples 2-11 studied the substrate scope by introducing various functional groups. The reaction results showed that the photocatalytic reaction of the present invention has good compatibility with both electron-rich and electron-deficient systems, and most substrates showed higher reactivity. Substrates with alkyl groups, including methyl (2b), ethyl (2c), propyl (2d), isopropyl (2e) and cyclopropyl (2f), had yields of 65%-74%. Notably, despite the steric crowding of phenyl (2g), 5-phenyl-3-amino-1,2,4-triazole had the highest reactivity with a yield of 81%. Halogen-substituted substrates showed slightly lower yields, with a yield of 63% for chlorine-substituted (2h) and 69% for bromine-substituted (2i). Notably, under these conditions, the strong electron-withdrawing -CF3 group also had good tolerance with a yield of 68% (2j). However, the yield using only the -OCH3 substituent was significantly lower, at 33% (2k).

[0115] Example 12

[0116] The difference between this example and Example 1 is: different reaction conditions. The reaction conditions and product yields are shown in Table 1.

[0117] Table 1 Yield Results of Example 12

[0118]

[0119]

[0120] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions of the present invention or make equivalent replacements, and these modifications or equivalent replacements cannot make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A photochemical synthesis method of an azotriazole compound, characterized in that, It includes the following steps: S1: Add a catalyst and a solvent into a reactor and stir; S2: Then add an aminotriazole compound and an inorganic base, and perform ultrasonic treatment until completely dissolved to obtain a reaction solution; wherein the chemical general formula of the aminotriazole compound is: S3: Place the reaction solution in a photoreactor, stir and irradiate with light. After the reaction is completed, obtain a mixed solution; S4: Concentrate the mixed solution under vacuum, add ultrapure water, centrifuge and filter to obtain a filter residue and a filtrate; S5: Adjust the pH value of the filtrate to neutral, let it stand overnight, filter, wash and dry to obtain an azotriazole compound.

2. The photochemical synthesis method of an azotriazole compound according to claim 1, characterized in that, In step S1, the catalyst is an Ir catalyst, the Ir catalyst is (Ir[dF(CF3)ppy]2(dtbpy))PF6, and the solvent is methanol.

3. The photochemical synthesis method of an azotriazole compound according to claim 1, characterized in that, In step S1, the addition amount of the catalyst is 0.5-1.5 mol% of the aminotriazole compound, and the ratio of the aminotriazole compound to the solvent is 1 mmol:8-20 mL.

4. A photochemical synthesis method of an azotriazole compound according to claim 1, characterized in that, In step S2, R is H, -CH3, -CH2CH3, -iPr, -nPr, cyclopropyl, -Ph, -Cl, -Br, -CF3 or -OCH3.

5. A photochemical synthesis method of an azotriazole compound according to claim 1, characterized in that, In step S2, the inorganic base is at least one of sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium carbonate, and potassium carbonate.

6. The photochemical synthesis method of an azotriazole compound according to claim 1, characterized in that, In step S2, the molar ratio of the aminotriazole compound to the inorganic base is 1:1-3.

7. A photochemical synthesis method of an azotriazole compound according to claim 1, characterized in that, In step S3, the conditions of light irradiation are: irradiate with an LED, the power is 1-15 W, and the wavelength is 350-700 nm.

8. A photochemical synthesis method of an azotriazole compound according to claim 1, characterized in that, In step S3, the light irradiation time is 20-30 h.

9. A photochemical synthesis method of an azotriazole compound according to claim 1, characterized in that, In step S4, the volume ratio of the solvent to the ultrapure water is 1:1-2.

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