Photocatalytic synthesis method of 2-amino naphthoselenazole compound

Abstract

The invention discloses a photocatalytic synthesis method of a 2-amino naphthoselenazole compound, and belongs to the technical field of organic synthesis. Under the irradiation of purple visible light, 2-isocyanaphthalene, selenium powder and tertiary amine are subjected to a one-pot reaction under the catalytic action of a semiconductor photocatalyst, and the 2-amido naphthoselenazole compound is obtained. According to the method, cheap and stable tertiary amine can be used as an amino source reagent, high-selectivity and high-yield preparation of the 2-amino naphthoselenazole compound is realized through a one-pot reaction, and the method does not need to additionally add an oxidizing agent, has the advantages of mild conditions, high atomic efficiency, easily available raw materials, environmental friendliness, simple product separation and purification and the like, and is suitable for industrial production. And large-scale production is facilitated.

Description

Technical Field

[0001] The present invention relates to a method for synthesizing 2-aminonaphthoselenazole compounds; in particular, it relates to a method for obtaining 2-aminonaphthoselenazole compounds with high selectivity and high yield through a one-pot reaction of 2-isocyanonaphthalene, selenium powder, and tertiary amine under the action of a semiconductor photocatalyst under purple visible light irradiation, belonging to the technical field of organic intermediate synthesis. Background Art

[0002] As important selenium- and nitrogen-containing heterocyclic compounds, 2-aminonaphthoselenazole compounds play an important role in the fields of organic electroluminescent materials and drug research and development. Organic electroluminescent (OLED) devices are widely used in the manufacture of various display products and lighting products. As a component in the structure of organic electroluminescent devices, organic electroluminescent materials have an important impact on their performance such as luminous efficiency and stability. Compared with traditional organic electroluminescent materials, naphthoselenazole and its derivatives such as pyrenoselenazole and other condensed heterocyclic compounds can effectively improve the performance of organic electroluminescent devices, such as having low driving voltage, high luminous efficiency, and long service life (CN 116082330 A, CN 115583936 A). In addition, selazole compounds have been widely used in the medical field due to their biological activities such as antioxidant, apoptosis induction, antiviral, and antitumor effects (Synlett. 2022, 33, 728.). Therefore, it is very urgent and important to develop an environmentally friendly, efficient, and convenient synthesis method for naphthoselenazole compounds. In 2023, (Green Chem., 2023, 25, 7983–7987) disclosed a method for synthesizing 2-aminonaphthoselenazole compounds by visible light catalyzed one-pot reaction of 2-isocyanonaphthalene, selenium powder, and secondary amine. Among them, the amine source reagent is secondary amine, and secondary amine reagents have high nucleophilicity, are incompatible with sensitive groups, and are prone to side reactions affecting the reaction effect. At the same time, secondary amine reagents have poor stability, are easily oxidized, and their prices are relatively expensive. In contrast, the price of tertiary amine is much lower than that of secondary amine, and it has good stability and weak nucleophilicity, with a wider reaction applicability. Due to the above advantages of tertiary amine, tertiary amine has been used as the amine source reagent in recent years. The research on selectively cleaving its C(sp 3 ) – N bond to introduce an amino group into the target compound structure has gradually attracted the attention of scientific researchers. The selective cleavage of the C(sp 3 ) - N bond of tertiary amine usually needs to be carried out under the conditions of transition metal catalysis and oxidant oxidation, and requires a relatively high reaction temperature. These traditional methods generally have the disadvantages of harsh reaction conditions, high cost, and environmental pollution.

[0003] 。 Summary of the Invention

[0004] Aiming at the limitations existing in the prior art, the object of the present invention is to provide a method for synthesizing 2-aminonaphthoselenazole compounds by a one-pot reaction of tertiary amines with 2-isocyanonaphthalene and selenium powder under the action of a cheap semiconductor photocatalyst under visible light irradiation. This method does not require the addition of metal catalysts and oxidants, realizes the selective cleavage of the tertiary amine C(sp 3 )-N bond under mild conditions, and obtains 2-aminonaphthoselenazole compounds in high yield by a one-pot method. Moreover, the reaction has low cost, is environmentally friendly, and is simple in separation and purification, which is conducive to large-scale production.

[0005] The 2-aminonaphthoselenazole compounds involved in the present invention have a typical naphthoselenazole parent structure, which has electroluminescent properties and can be used as organic electroluminescent materials for light-emitting devices.

[0006] To achieve the above technical object, the present invention provides a photocatalytic synthesis method of 2-aminonaphthoselenazole compounds. This method is a one-pot reaction of 2-isocyanonaphthalene, selenium powder and tertiary amines under the catalytic action of a semiconductor photocatalyst under purple visible light irradiation to obtain 2-aminonaphthoselenazole compounds;

[0007] The 2-isocyanonaphthalene has the structure of formula 1:

[0008]

[0009] Formula 1

[0010] The tertiary amine has the structure of formula 2:

[0011]

[0012] Formula 2

[0013] The 2-aminonaphthoselenazole compound has the structure of formula 3:

[0014]

[0015] Formula 3

[0016] Among them,

[0017] R 1 、R 2 and R 3 are independently selected from alkyl groups, naphthyl groups, phenyl groups or substituted phenyl groups of C1~C 12 . The substituents in the substituted phenyl groups are selected from at least one of alkyl groups of C1~C5, alkoxy groups of C1~C5, and halogen substituents.

[0018] As a preferred embodiment, the halogen substituent is fluorine, chlorine, bromine or iodine.

[0019] In the tertiary amine and 2-aminonaphthoselenazole compound of the present invention, R 1 , R 2 and R 3 The group can be selected from alkyl or aryl. 1 , R 2 and R 3 When the group selects an alkyl group, the number of carbon atoms is C1~C 12 The alkyl group may be a straight-chain alkyl group. When the number of carbon atoms exceeds 3, it may also be a branched alkyl group or a cycloalkyl group. The straight-chain alkyl group or the branched alkyl group may include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, hexyl, octyl, decyl, dodecyl, etc. The cycloalkyl group may include cyclopentane, cyclohexane, cycloheptane, etc. 1 , R 2 and R 3 When the group selects an aryl group, the aryl group is a naphthyl group, a phenyl group or a phenyl group containing a substituent. The phenyl group containing a substituent is a phenyl ring containing a conventional substituent. The position of the substituent on the benzene ring is not limited. The number of substituents is one or more. The substituents that can be selected include C1~C5 alkyl groups (such as methyl, ethyl, propyl, butyl, etc.), C1~C5 alkoxy groups (such as methoxy, ethoxy, butoxy, etc.), halogen substituents (such as fluorine substituents, chlorine substituents, bromine substituents or iodine substituents), etc. R 1 , R 2 and R 3 The type of substituent has a certain influence on the reaction of synthesizing 2-aminonaphthothracene selenazole compounds, mainly based on the R 1 , R 2 and R 3 C(sp 3 ) - N bond cleavage activities are different, for example, cleavage activity: allyl>methyl>ethyl>isopropyl>long-chain alkyl, but within the preferred range, by optimizing the reaction conditions, the yield of 2-aminonaphthoselenazole compounds is maintained above 75%.

[0020] As a preferred solution, the wavelength of the purple visible light is 390-395 nm. The reaction of the present invention responds to both blue visible light and green visible light, and the reaction can proceed smoothly, but the reaction yield is highest under the irradiation of purple visible light.

[0021] As a preferred solution, the purple visible light is provided by a 5-10 W LED purple light source. The purple visible light is further provided by a 7-10 W LED purple light source, and most preferably by a 10 W LED purple light source. If the power of the purple light source is too low, the reaction yield will be affected to varying degrees.

[0022] As a preferred embodiment, the molar ratio of the 2-isocyanonaphthalene to the tertiary amine is 1:2 to 5. The theoretical reaction molar ratio of 2-isocyanonaphthalene to the tertiary amine is 1:1, but using an appropriate excess of the tertiary amine is beneficial to improving the reaction yield of the 2-aminonaphtho[2,3-d]selenazole compound. The optimal reaction molar ratio of 2-isocyanonaphthalene to the tertiary amine is 1:3.

[0023] As a preferred embodiment, the molar ratio of the 2-isocyanonaphthalene to the selenium powder is 1:1 to 2. The selenium powder is elemental selenium. Commercially available powdered elemental selenium theoretically all adapts to this reaction, and preferably the selenium powder with a mesh size of 200 to 300 commonly available on the market is used.

[0024] As a preferred embodiment, the reaction medium used in the one-pot reaction includes at least one of 1,2-dichloroethane, dimethyl sulfoxide, and N,N-dimethylformamide. Using 1,2-dichloroethane, N,N-dimethylformamide, or dimethyl sulfoxide as the reaction medium can all enable the reaction to proceed smoothly, but 1,2-dichloroethane is the optimal reaction medium.

[0025] As a more preferred embodiment, the reaction medium contains water; the addition amount of the water is 2 to 3 times the molar amount of the 2-isocyanonaphthalene. And adding an appropriate amount of water can significantly promote the reaction to proceed.

[0026] As a preferred embodiment, the semiconductor photocatalyst is tungsten trioxide and / or BiVO4. The reaction involved in the present invention is relatively sensitive to the type of semiconductor photocatalyst. Using WO3, g-C3N4, TiO2, CdS, BiVO4, WS2, etc. as the semiconductor photocatalyst all has a certain promoting effect on this reaction, and tungsten trioxide and / or BiVO4 are semiconductor photocatalysts with relatively good effects, especially tungsten trioxide is the optimal semiconductor photocatalyst.

[0027] As a preferred embodiment, the dosage of the semiconductor photocatalyst relative to the dosage of the 2-isocyanonaphthalene is 2 to 8 mg / mmol. Within the preferred range, as the dosage of the semiconductor photocatalyst increases, the reaction yield of the 2-aminonaphtho[2,3-d]selenazole compound first increases and then levels off. When the dosage of the semiconductor photocatalyst relative to the 2-isocyanonaphthalene reaches 5 mg / mmol, the best reaction effect is achieved. When it is lower than 5 mg / mmol, the reaction yield will decrease, and when it is higher than 5 mg / mmol, the change in the reaction yield is not obvious. Therefore, the optimal dosage of the semiconductor photocatalyst relative to the 2-isocyanonaphthalene is 5 to 10 mg / mmol.

[0028] As a preferred embodiment, the conditions for the one-pot reaction are: the temperature is room temperature, and the time is 8 to 12 hours.

[0029] The route for synthesizing N,N - diethylaminonaphthoselenazole compounds by the visible - light catalytic reaction of 2 - isocyanonaphthalene, selenium powder and tertiary amine (taking 2 - isocyanonaphthalene, triethylamine, WO3 photocatalyst, 1,2 - dichloroethane as the reaction medium as an example) is as follows:

[0030]

[0031] Through control experiments and reference documents, a possible reaction mechanism is proposed. Photo - generated electrons reduce molecular oxygen in the air to superoxide radicals. At the same time, photo - generated holes oxidize ground - state Et3N to radical cation A, and A is further oxidized by holes to obtain iminium cation B. Then, B undergoes hydrolysis to form diethylamine and acetaldehyde. Under the catalysis of tertiary amine, 2 - isocyanonaphthalene reacts with selenium powder to form 2 - naphthylisoselenocyanate, which is then subjected to a nucleophilic attack by diethylamine to be transformed into intermediate C. C undergoes an intramolecular rearrangement, releasing a hydroxyl anion and migrating an aryl group to obtain alkyl dihydro - selenate D, and D undergoes hydrolysis to obtain the target product.

[0032]

[0033] Compared with the prior art, the beneficial technical effects brought by the technical solution of the present invention are as follows:

[0034] 1) The present invention uses WO3 as a photocatalyst, which is safe, cheap and easily available;

[0035] 2) The present invention uses a 10 - W purple LED as a light source, which is safe, energy - saving, green and environmentally friendly;

[0036] 3) The present invention has a wide selectivity for the use of tertiary amines and good functional - group compatibility;

[0037] 4) The reaction steps of the present invention are simple, a one - pot reaction can be achieved, and the reaction conditions are mild. Without using metal catalysts and organic oxidants, the product is easy to separate, and the product yield is high and the selectivity is good. Brief Description of the Drawings

[0038] Figure 1 For N,N - diethylaminonaphthoselenazole 1 H NMR.

[0039] Figure 2 For N,N - diethylaminonaphthoselenazole 13 C NMR. Detailed Embodiments

[0040] The following specific embodiments are intended to further illustrate the content of the present invention rather than limit the protection scope of the claims of the present invention.

[0041] The reaction of 2-isocyanonaphthalene, selenium powder and triethylamine under the optimal reaction conditions was used as the standard reaction, and the specific reaction formula is as follows:

[0042]

[0043] The specific operation steps are as follows: In a 10 mL quartz reaction tube, 2-isocyanonaphthalene (0.20 mmol), selenium powder (0.30 mmol), triethylamine (0.60 mmol), tungsten trioxide (10 mg), water (0.40 mmol) and DCE (2.0 mL) were added in sequence, and irradiated with visible light of purple LEDs with a light source power of 10 W (wavelength 395 nm) and stirred at room temperature. After the reaction was completed, 5 mL of water was added to the reaction mixture, extracted with dichloromethane (3 mL×2), the organic phases were combined, washed with saturated brine, concentrated in vacuo after drying, and the yield was analyzed by crude NMR spectrum.

[0044]

[0045] In the above table, in experimental groups 1-3, the influence of different visible light sources on the reaction was investigated. It can be seen from the experimental data that the reaction can proceed smoothly under the irradiation of visible light of different colors of LEDs, but the reaction is more sensitive to the wavelength of visible light. Among them, purple LEDs are the best light sources for the reaction, and the reaction yield is the highest.

[0046] In the above table, in experimental groups 1, 4-5, the influence of the light source power on the reaction was investigated. The experimental results show that when 5 W or 7 W purple LED light sources are used to replace the 10 W LED light source, the reaction can proceed smoothly, but the reaction yield decreases to a certain extent, indicating that the 10 W purple LED is the best light source for the reaction.

[0047] In the above table, in experimental groups 1, 6-11, the influence of different semiconductor photocatalysts on the reaction was investigated. The catalytic effects of various semiconductor photocatalysts including g-C3N4, TiO2, CdS, BiVO4 and WS2 are all lower than that of WO3. In addition, the reaction cannot proceed without adding a photocatalyst.

[0048] In the above table, in experimental groups 1, 12-14, the influence of the water addition amount on the reaction effect was investigated. The results show that appropriately increasing the water will increase the yield of the target product, but when the addition amount is too high or no water is added, the reaction effect also decreases to a certain extent.

[0049] In the above table, in experimental groups 1, 15-18, different reaction media were investigated. The experiments show that when DMSO, DMF, MeCN, THF are used to replace DCE as the reaction medium, the reaction can also proceed smoothly, but the yields all decrease to varying degrees, indicating that DCE is the best reaction medium.

[0050] In the above table, Experiment Groups 1 and 19 investigated the effect of light on the reaction. The experimental results showed that the reaction could not proceed under light - shielding conditions.

[0051] Examples 1 - 5

[0052] In the following Examples 1 - 5, the reactions were all carried out under the optimal reaction conditions. The specific reaction equations are as follows. The main purpose was to investigate the yield of different substrates under the optimal conditions:

[0053] The specific operation steps were as follows: In a 10 - mL quartz reaction tube, 2 - isocyanonaphthalene (0.30 mmol), selenium powder (0.45 mmol), tertiary amine (0.90 mmol), tungsten trioxide (15 mg), water (0.60 mmol), and DCE (3.0 mL) were added in sequence. Visible light irradiation with Blue LEDs (wavelength 395 nm) with a light source power of 10 W was carried out, and the reaction was stirred at room temperature. After the reaction was completed, 5 mL of water was added to the reaction mixture, and it was extracted with dichloromethane (3 mL×2). The organic phases were combined, washed with saturated brine, dried, concentrated under vacuum, and purified by column chromatography to obtain the target compound.

[0054] Example 1

[0055] Compound 1: Yield 93%, N,N - diethylnaphtho[2,1 - d][1,3]selenazol - 2 - amine, the tertiary amine reagent was triethylamine;

[0056]

[0057] 1 H NMR (400 MHz, CDCl3) δ 7.86 (d, J = 8.4 Hz, 1H), 7.78–7.74 (m, 2H),7.60 (d, J = 8.4 Hz, 1H), 7.48 (t, J = 7.6 Hz, 1H), 7.37 (t, J = 7.6 Hz, 1H),3.61 (q, J = 7.2 Hz, 4H), 1.34 (t, J = 7.2 Hz, 6H);

[0058] 13 C NMR (100 MHz, CDCl3) δ 168.2, 152.6, 130.6, 129.1, 128.7, 126.6,126.5, 125.7, 123.5, 120.5, 46.6, 12.8.

[0059] Example 2

[0060] Compound 2: Yield 86%, N-methyl-N-octylnaphtho[2,1-d][1,3]selenazol-2-amine, the tertiary amine reagent is N,N-dimethyloctylamine;

[0061]

[0062] 1 H NMR (400 MHz, CDCl3) δ 7.88-7.78 (m, 3H), 7.64-7.62 (m, 1H), 7.51-7.48 (m, 1H), 7.40-7.37 (m, 1H), 3.56-3.52 (t, J = 7.6 Hz, 2H), 3.24 (s, 3H),1.77-1.72 (m, 2H), 1.38-1.32 (m, 10H), 0.94-0.91 (t, J = 7.5 Hz, 3H);

[0063] 13 C NMR (100 MHz, CDCl3) δ 169.4, 152.9, 130.7, 129.4, 129.1, 128.8,126.74, 126.6, 125.8, 123.6, 120.7, 55.1, 38.8, 31.9, 29.4, 29.3, 27.3, 26.9,22.7, 14.2.

[0064] Example 3

[0065] Compound 3: Yield 79%, 2-(pyrrolidin-1-yl)naphtho[2,1-d][1,3]selenazole, the tertiary amine reagent is 1-methylpyrrolidine;

[0066]

[0067] 1 H NMR (400 MHz, CDCl3) δ 7.85 (d, J = 8.4 Hz, 1H), 7.80-7.72 (m, 2H),7.60 (d, J = 8.4 Hz, 1H), 7.47 (t, J = 7.6 Hz, 1H), 7.36 (t, J = 7.6 Hz, 1H),3.58 (d, J = 6.4 Hz, 4H), 2.10-2.03 (m, 4H);

[0068] 13 13C NMR (100 MHz, CDCl3) δ 166.0, 152.8, 130.7, 129.2, 128.9, 128.7, 126.7, 126.5, 125.7, 123.5, 120.6, 50.4, 25.6.

[0069] Example 4

[0070] Compound 4: Yield 88%, N-cyclohexyl-N-methylnaphtho[2,1-d][1,3]selenazol-2-amine, the tertiary amine reagent is N,N-dimethylcyclohexylamine;

[0071]

[0072] 1 1H NMR (400 MHz, CDCl3) δ 7.85 (d, J = 8.4 Hz, 1H), 7.74 (s, 2H), 7.60 (d, J = 8.4

[0073] Hz, 1H), 7.50 - 7.44 (m, 1H), 7.36 (t, J = 7.6 Hz, 1H), 3.85 (s, 1H), 3.11 (s, 3H), 1.97 - 1.87 (m, 4H), 1.75 - 1.71 (m, 1H), 1.60 - 1.41 (m, 4H), 1.21 - 1.11 (m, 1H);

[0074] 13 13C NMR (100 MHz, CDCl3) δ 169.8, 152.6, 130.6, 129.0, 128.7, 128.6, 126.6, 126.5, 125.7, 123.5, 120.6, 62.2, 33.3, 30.1, 25.8, 25.4.

[0075] Example 5

[0076] Compound 5: Yield 78%, N-phenyl-N-methylnaphtho[2,1-d][1,3]selenazol-2-amine, the tertiary amine reagent is N,N-dimethylaniline;

[0077]

[0078] 11H NMR (400 MHz, CDCl3) δ 7.86 (d, J = 8.4 Hz, 1H), 7.82–7.76 (m, 2H),7.51–7.48 (m, 5H), 7.45–7.35 (m, 3H), 3.69 (s, 3H);

[0079] 13 13C NMR (100 MHz, CDCl3) δ 169.6, 152.3, 147.1, 130.5, 130.1, 129.8,129.6, 128.7, 127.7, 126.7, 126.5, 125.9, 125.8, 123.9, 120.8, 40.4

Claims

1. A photocatalytic synthesis method of 2-aminonaphthoselenazole compounds, characterized in that: Under the irradiation of purple visible light, 2-isocyanonaphthalene, selenium powder and tertiary amine react in one pot under the catalysis of a semiconductor photocatalyst to obtain a 2-aminonaphtho[2,1-d]selenazole compound; The 2-isocyanonaphthalene has the structure of Formula 1: ； Formula 1 The tertiary amine has the structure of Formula 2: ； Formula 2 The 2-aminonaphtho[2,1-d]selenazole compound has the structure of Formula 3: ； Formula 3 Wherein, R 1 , R 2 and R 3 are independently selected from C1 - C 12 alkyl, naphthyl, phenyl or substituted phenyl, wherein the substituents of the substituted phenyl are selected from at least one of C1 - C5 alkyl, C1 - C5 alkoxy, and halogen substituents.

2. The photocatalytic synthesis method of a 2-aminonaphthoselenazole compound according to claim 1, characterized in that: The halogen substituent is fluorine, chlorine, bromine or iodine.

3. The photocatalytic synthesis method of a 2-aminonaphthoselenazole compound according to claim 1 or 2, characterized in that: The wavelength of the purple visible light is 390 - 395 nm.

4. The photocatalytic synthesis method of a 2-aminonaphthoselenazole compound according to claim 3, characterized in that: The purple visible light is provided by a 5 - 10 W LED purple light source.

5. A photocatalytic synthesis method of a 2-aminonaphtho[2,1-d]selenazole compound according to claim 1, characterized in that: The molar ratio of the 2-isocyanonaphthalene to the tertiary amine is 1:2 - 5; The molar ratio of the 2-isocyanonaphthalene to the selenium powder is 1:1 - 2.

6. The photocatalytic synthesis method of a 2-aminonaphthoselenazole compound according to claim 1, characterized in that: The reaction medium used in the one-pot reaction includes at least one of 1,2-dichloroethane, dimethyl sulfoxide and N,N-dimethylformamide.

7. The photocatalytic synthesis method of a 2-aminonaphthoselenazole compound according to claim 6, characterized in that: The reaction medium contains water; the addition amount of water is 2 - 3 times the molar amount of 2-isocyanonaphthalene.

8. The photocatalytic synthesis method of a 2-aminonaphthoselenazole compound according to claim 1, characterized in that: The semiconductor photocatalyst is tungsten trioxide and / or BiVO4.

9. The photocatalytic synthesis method of a 2-aminonaphthoselenazole compound according to claim 8, characterized in that: The dosage of the semiconductor photocatalyst relative to the dosage of the 2-isocyanonaphthalene is 3 - 10 mg / mmol.

10. A photocatalytic synthesis method of a 2-aminonaphthoselenazole compound according to claim 1, 2, 4, 5, 6, 7, 8 or 9, characterized in that: The conditions of the one-pot reaction are: the temperature is room temperature and the time is 8 - 12 hours.

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