A quinoline derivative photocatalyst, its preparation method, and its application in catalytic alcohol oxidation.

Abstract

This invention relates to the field of photocatalyst technology, specifically to a quinoline derivative photocatalyst, its preparation method, and its application in the catalytic oxidation of alcohols. Through the conjugation effect of the cyano group and the quinoline ring, the absorption range of the quinoline derivative is within the visible or ultraviolet light range, meeting the basic requirements of visible light photocatalysis. Simultaneously, the ortho position of the quinoline N group is relatively reactive and readily participates in the reaction; therefore, a group must occupy the reaction site to ensure the stability of the compound.

Description

Technical Field

[0001] This invention relates to the field of photocatalyst technology, specifically to a quinoline derivative photocatalyst, its preparation method, and its application in catalytic alcohol oxidation. Background Technology

[0002] Photocatalytic reactions have advantages such as mild conditions and few side reactions. With the selection of a suitable photocatalyst, corresponding organic synthesis reactions can be completed efficiently. The earliest photocatalytic reaction can be traced back to 1972, when Fujishima and Honda (Nature 1972, 238(5358), 37-8.) discovered that using TiO2 as a catalyst could decompose water to produce hydrogen under ultraviolet light. However, the application of photocatalysis in organic synthesis did not flourish until after 2008. In 2008, MacMillan (Science 2008, 322(5898), 77-80) and Yoon's research group (J Am Chem Soc 2008, 130(39), 12886-7.) used the tris(2,2'-bipyridine)ruthenium complex Ru(bpy)3Cl2 as a photocatalyst to realize the asymmetric alkylation reaction and intramolecular [2+2] cycloaddition reaction of aldehydes under visible light conditions. Subsequently, Stephenson et al. (J Am ChemSoc 2009, 131(25), 8756-7.) also achieved selective dehalogenation under mild conditions using the same photo-redox catalyst.

[0003] In organic photocatalytic synthesis reactions, the most commonly used photoredox catalysts are currently ruthenium(II) polypyridine complexes and iridium(III) phenylpyridine complexes, which have advantages such as chemical stability and long excited-state lifetimes. However, as noble metal catalysts, ruthenium and iridium complexes have disadvantages such as limited reserves, high prices, and heavy metal toxicity. Although chemists hope to develop inexpensive transition metal photocatalysts centered on iron, cobalt, etc., their short excited-state lifetimes make it difficult to complete electron transfer processes (J Phys Chem Lett 2018, 9(3), 459-463.), and they cannot well replace noble metal photocatalysts in practical applications.

[0004] Organic small-molecule photocatalysts possess advantages such as environmental friendliness, low cost, and easy structural modification, making them an ideal class of photocatalysts. They have been widely used in photocatalytic organic synthesis and have shown potential to replace noble metal photocatalysts. Common organic photocatalysts include acridine onium salts (Org Lett 2005, 7(19), 4265-8), 4CzIPN (ACSCatal. 2016, 6(2), 873-877.), and diaryl ketones (J Am Chem Soc 2018, 140(38), 12200-12209.). In the development of organic small-molecule photocatalysts, current research mainly focuses on modifying existing frameworks. By changing substituents, the reactivity of photocatalysts can be adjusted within certain limits. Research on developing new frameworks as the core structure of photocatalysts is relatively limited. Based on this, it is of great significance to adjust the structure of photocatalysts to obtain inexpensive, structurally tunable, stable, and highly catalytically active small organic molecule photocatalysts, so as to achieve the synthesis of high-value-added organic compounds under mild and green conditions.

[0005] Carbonyl compounds are important functional groups in drug and material molecules, and the synthesis of carbonyl compounds through alcohol oxidation is one of the fundamental reactions in organic synthesis. Traditional methods typically use strong oxidants, such as potassium permanganate, p-chloroperoxybenzoic acid, and peroxytert-butanol, which have drawbacks such as harsh conditions, low atom economy, and dangerous operation. In contrast, green catalytic oxidation processes using air or oxygen as oxidants have significant advantages. The Stahl group (J Am Chem Soc 2011, 133(42), 16901-10.) and the Aso Akira group (Adv. Synth. Catal. 2011, 353(6), 1005-1017.) developed the CuI / OTf / bpy / NMI system and the Fe(NO3)3·9H2O / TEMPO system, respectively, to achieve selective oxidation of alcohols using oxygen as an oxidant. However, in these transition metal-involved systems, the catalyst dosage is high, and various additives need to be introduced.

[0006] Photocatalysis can achieve selective oxidation of alcohols in a simple system using only a photocatalyst and oxygen, under mild and environmentally friendly conditions. The Kokotos group (Green Chem. 2020, 22(2), 471-477.) and the Song group (J OrgChem 2023, 88(7), 4765-4769.) used thioxanthone and eosin Y as photocatalysts, respectively, with oxygen as the oxidant, to oxidize primary alcohols or secondary benzyl alcohols to the corresponding aldehydes or ketones. However, these reactions require 5 mol%-20 mol% of photocatalyst and have relatively long reaction times. Therefore, developing a small-molecule organic photocatalyst with high catalytic activity, short reaction time, and low catalyst dosage to achieve alcohol oxidation under mild and environmentally friendly conditions is a pressing technical challenge in this field. Summary of the Invention

[0007] In view of this, the present invention aims to provide a quinoline derivative with high catalytic activity, short reaction time and low catalyst dosage. Compared with common commercial photocatalysts, this type of catalyst is simple to synthesize, easy to modify in structure, and has good stability. It can be excited in the visible light range and has a high excited-state reduction potential. Therefore, it has significant advantages in the oxidation reaction of alcohols. It can achieve efficient and selective catalytic oxidation of alcohols under air conditions with low catalyst dosage to obtain the corresponding ketones or acids.

[0008] Furthermore, the present invention also provides a method for preparing the above-mentioned quinoline derivative.

[0009] Furthermore, the present invention also provides an application of the above-mentioned quinoline derivative in the catalytic oxidation of alcohols to ketones or carboxylic acids.

[0010] To achieve the above objectives, the present invention adopts the following technical solution:

[0011] In a first aspect, the present invention provides a quinoline derivative having a structure as shown in Formula I:

[0012]

[0013] Wherein, R is a halogen or aryl group;

[0014] X is either hydrogen or alkoxy;

[0015] Y is an alkyl, halogen, amino, or alkoxy group.

[0016] In one alternative embodiment, the aryl group is a substituted or unsubstituted phenyl group.

[0017] In one alternative embodiment, when X is an alkoxy group, the alkoxy group contains 1-6 carbon atoms.

[0018] In one alternative embodiment, when Y is an alkyl group, the alkyl group is a C1-C10 alkyl group.

[0019] In one alternative embodiment, when Y is a halogen, the halogen is fluorine, chlorine, bromine, or iodine.

[0020] In an alternative embodiment, when Y is an amino group, the amino group is NR1R2, wherein R1 and R2 are each independently selected from H or C1-C3 alkyl groups.

[0021] In one alternative embodiment, when Y is an alkoxy group, the alkoxy group contains 1-6 carbon atoms.

[0022] In one alternative embodiment, the substituted phenyl group contains at least one electron-donating or electron-withdrawing group.

[0023] In one alternative embodiment, the electron-withdrawing group is at least one of halogen, cyano, and carbonyl.

[0024] In one alternative embodiment, the electron-donating group is at least one of alkyl, alkoxy, and amino groups.

[0025] In one alternative embodiment, when the electron-withdrawing group is a halogen, the halogen is fluorine, chlorine, bromine, or iodine.

[0026] In one optional embodiment, when the electron-withdrawing group is a carbonyl group, the carbonyl group contains 1-6 carbon atoms, and the carbonyl group includes, but is not limited to, ketones, aldehydes, carboxylic acids, esters, and amides.

[0027] In one alternative embodiment, when the electron-donating group is an alkyl group, the alkyl group is a C1-C5 alkyl group.

[0028] In one alternative embodiment, when the electron-donating group is an alkoxy group, the alkoxy group contains 1-6 carbon atoms.

[0029] In one alternative embodiment, when the electron-donating group is an amino group, the amino group is NR1R2, wherein R1 and R2 are each independently selected from H or C1-C3 alkyl groups.

[0030] In one alternative embodiment, the quinoline derivative has the following structure:

[0031]

[0032] Secondly, the present invention provides a method for preparing the above-mentioned quinoline derivative, wherein when R is a substituted or unsubstituted phenyl group, the method includes method 1 or method 2, wherein:

[0033] Method 1 includes the following steps:

[0034] (1) Compound II reacts with an oxidizing agent to give compound III;

[0035] (2) Compound III reacts with a cyaniding reagent to give compound IV;

[0036] (3) Compound IV reacts with arylboronic acid to give the compound shown in Formula I;

[0037]

[0038] Method 2 includes the following steps:

[0039] (1) Compound II reacts with arylboronic acid to give compound V;

[0040] (2) Compound V reacts with an oxidizing agent to give compound VI;

[0041] (3) Compound VI reacts with a cyaniding reagent to give a compound as shown in Formula I;

[0042]

[0043] When R is a halogen, method 3 is used, including the following steps:

[0044] (1) Compound II reacts with an oxidizing agent to give compound III;

[0045] (2) Compound III reacts with a cyaniding reagent to give compound I;

[0046]

[0047] In compound II, Z is fluorine, chlorine, bromine, or iodine.

[0048] In an optional embodiment, in step (1) of method 1, the oxidant is at least one of 3-chloroperoxybenzoic acid, H2O2, and NaClO.

[0049] In an alternative embodiment, in step (1) of method 1, the reaction further includes using a solvent, the solvent being at least one of dichloromethane, ethyl acetate, and 1,2-dichloroethane.

[0050] In an alternative embodiment, in step (1) of method 1, the molar ratio of compound II to the oxidant is 1:1-5.

[0051] In one alternative implementation, in step (1) of method 1, the reaction is carried out at room temperature for 5-20 hours.

[0052] In an alternative embodiment, in step (2) of method 1, the molar ratio of compound III to the cyaniding agent is 1:1-5.

[0053] In an alternative embodiment, in step (2) of method 1, the cyaniding agent is trimethylsilane cyano.

[0054] In one alternative implementation, in step (2) of method 1, the reaction temperature is 80℃-150℃ and the reaction time is 2h-10h.

[0055] In an optional embodiment, in step (3) of method 1, the arylboronic acid is a substituted or unsubstituted phenylboronic acid; the substituted phenylboronic acid contains at least one electron-withdrawing group or electron-donating group; the electron-withdrawing group is at least one of halogen, cyano, and carbonyl; the electron-donating group is at least one of alkyl, alkoxy, and amino; preferably, when the electron-withdrawing group is a halogen, the halogen is fluorine, chlorine, bromine, or iodine; and / or, when the electron-withdrawing group is a carbonyl, the carbonyl contains 1-6 carbon atoms; and / or, when the electron-donating group is an alkyl, the alkyl is C1-C5 alkyl; and / or, when the electron-donating group is an alkoxy, the alkoxy contains 1-6 carbon atoms; and / or, when the electron-donating group is an amino, the amino is NR1R2, wherein R1 and R2 are each independently selected from H or C1-C3 alkyl.

[0056] In an optional embodiment, in step (3) of method 1, the reaction further includes a catalyst and an alkaline reagent, wherein the catalyst is a tetra-triphenylphosphine palladium, or a complex of palladium acetate or palladium chloride with a ligand, wherein the ligand is at least one of tri-n-butylphosphine, triphenylphosphine, and tricyclohexylphosphine, and when it is a complex, the ligand is in excess, based on the amount of metallic palladium.

[0057] In an optional embodiment, in step (3) of method 1, the alkaline reagent is at least one of K2CO3, Cs2CO3, Na2CO3, and CsF.

[0058] In an alternative embodiment, in step (3) of method 1, the reaction further includes the use of a solvent, which is a mixed solution of toluene, ethanol and water in a volume ratio of 1-5:1:0.1-1.

[0059] In an optional embodiment, in step (3) of method 1, the molar ratio of compound IV, the arylboronic acid, the catalyst and the basic reagent is 1:1-8:0.01-0.4:2-12.

[0060] In one alternative implementation, in step (3) of method 1, the reaction temperature is 60°C-140°C and the reaction time is 5h-24h.

[0061] In an optional embodiment, in step (1) of method 2, the arylboronic acid is a substituted or unsubstituted phenylboronic acid; the substituted phenylboronic acid contains at least one electron-withdrawing group or electron-donating group; the electron-withdrawing group is at least one of halogen, cyano, and carbonyl; the electron-donating group is at least one of alkyl, alkoxy, and amino; preferably, when the electron-withdrawing group is a halogen, the halogen is fluorine, chlorine, bromine, or iodine; and / or, when the electron-withdrawing group is a carbonyl, the carbonyl contains 1-6 carbon atoms, and the carbonyl includes, but is not limited to, ketones, aldehydes, carboxylic acids, esters, and amides; and / or, when the electron-donating group is an alkyl, the alkyl is C1-C5 alkyl; and / or, when the electron-donating group is an alkoxy, the alkoxy contains 1-6 carbon atoms; and / or, when the electron-donating group is an amino, the amino is NR1R2, wherein R1 and R2 are each independently selected from H or C1-C3 alkyl.

[0062] In an alternative embodiment, in step (1) of method 2, the reaction further includes a catalyst and a basic reagent, wherein the catalyst is a tetra-triphenylphosphine palladium, or a complex of palladium acetate or palladium chloride with a ligand, wherein the ligand is at least one of tri-n-butylphosphine, triphenylphosphine, and tricyclohexylphosphine.

[0063] In an optional embodiment, in step (1) of method 2, the alkaline reagent is at least one of K2CO3, Cs2CO3, and Na2CO3.

[0064] In an alternative embodiment, in step (1) of method 2, the reaction further includes the use of a solvent, which is a mixed solution of tetrahydrofuran, methanol and water in a volume ratio of 1:0.2-1:0.1-1.

[0065] In an optional embodiment, in step (1) of method 2, the molar ratio of compound II, the arylboronic acid, the catalyst and the basic reagent is 1:1-8:0.01-0.4:2-12.

[0066] In one alternative implementation, in step (1) of method 2, the reaction temperature is 60°C-120°C and the reaction time is 1-5 days.

[0067] In an optional embodiment, in step (2) of method 2, the oxidant is at least one of 3-chloroperoxybenzoic acid, H2O2, and NaClO.

[0068] In an alternative embodiment, in step (2) of method 2, the reaction further includes using a solvent, the solvent being at least one of dichloromethane, ethyl acetate, and 1,2-dichloroethane.

[0069] In an alternative embodiment, in step (2) of method 2, the molar ratio of compound V to the oxidant is 1:1-5.

[0070] In one alternative implementation, in step (2) of method 2, the reaction temperature is room temperature and the reaction time is 15h-20h.

[0071] In an alternative embodiment, in step (3) of method 2, the molar ratio of compound VI to the cyaniding agent is 1:1-5.

[0072] In an alternative embodiment, in step (3) of method 2, the cyaniding agent is at least one of trimethylsilane cyano.

[0073] In one alternative implementation, in step (3) of method 2, the reaction temperature is 80℃-150℃ and the reaction time is 3h-10h.

[0074] In an optional embodiment, in step (1) of method 3, the oxidant is at least one of 3-chloroperoxybenzoic acid, H2O2, and NaClO.

[0075] In an alternative embodiment, in step (1) of method 3, the reaction further includes using a solvent, the solvent being at least one of dichloromethane, ethyl acetate, and 1,2-dichloroethane.

[0076] In an alternative embodiment, in step (1) of method 3, the molar ratio of compound II to the oxidant is 1:1-5.

[0077] In an alternative implementation, in step (1) of method 3, the reaction is carried out at room temperature for 5-20 hours.

[0078] In an alternative embodiment, in step (2) of method 3, the molar ratio of compound III to the cyaniding agent is 1:1-5.

[0079] In an alternative embodiment, in step (2) of method 3, the cyaniding agent is trimethylsilane cyano.

[0080] In one alternative embodiment, in step (2) of method 3, the reaction temperature is 80℃-150℃ and the reaction time is 2h-10h.

[0081] In an optional implementation, after any step of method 1, method 2, or method 3 has been completed, a purification step is further included:

[0082] After the reaction is complete, the reaction mixture is extracted, the organic layers are combined, dried, concentrated, and the crude product is purified by column chromatography to obtain the target product. The eluent used is petroleum ether and ethyl acetate in a volume ratio of 1-10:1, or ethyl acetate:methanol in a volume ratio of 20:1, or petroleum ether.

[0083] Thirdly, the present invention also provides the application of the above-mentioned quinoline derivatives, after protonation, as photocatalysts in the catalytic oxidation of alcohols to ketones or carboxylic acids.

[0084] Fourthly, the present invention provides a method for oxidizing alcohols, comprising the following steps:

[0085] Under ultraviolet or visible light conditions, in the presence of photocatalysts and oxidants, alcohols are oxidized to produce ketones or carboxylic acids;

[0086] The photocatalyst is a protonated product of the aforementioned quinoline derivative.

[0087] In one alternative embodiment, the oxidant is air or oxygen.

[0088] In one alternative embodiment, the oxidation reaction is carried out in a photoreactor with an electrical power of 5W-60W.

[0089] In one alternative embodiment, the molar ratio of the alcohol to the photocatalyst is 10-200:1.

[0090] In one alternative embodiment, the oxidation method further includes using a solvent, said solvent being at least one of ethyl acetate, dichloromethane, dichloroethane, dimethyl sulfoxide, chlorobenzene, acetonitrile, and water.

[0091] In one optional implementation, the light wavelength is 360-500 nm and the reaction time is 2h-24h.

[0092] In one alternative embodiment, the solvent is chlorobenzene and acetonitrile in a volume ratio of 0.1-10:1.

[0093] In one alternative embodiment, the alcohol is oxidized to a carboxylic acid when it is a primary alcohol, or oxidized to a ketone when it is a secondary alcohol.

[0094] Compared with the prior art, the technical solution of the present invention has the following advantages:

[0095] 1. The quinoline derivatives provided by this invention, through the conjugation effect of the cyano group and the quinoline ring, enable the absorption range of the quinoline derivatives to be within the visible or ultraviolet light range, thus meeting the basic requirements of visible light photocatalysis. Simultaneously, the ortho position of quinoline N is relatively reactive and readily participates in the reaction; the cyano group occupies this reaction site to ensure the stability of the compound. Furthermore, the quinoline derivatives of this invention possess a high excited-state reduction potential, and after protonation, can achieve highly efficient and selective catalytic oxidation of alcohols under air conditions with low dosage.

[0096] 2. The method for preparing quinoline derivatives provided by this invention uses commercially available compound II as raw material, and the target product can be obtained by sequential oxidation, cyanation and alkylation reactions or alkylation followed by oxidation and cyanation reactions. The yield is in the medium to high range and it is applicable to a variety of substituent groups. The purification process is simple and fast, and it is a highly efficient synthetic process worthy of promotion.

[0097] 3. The quinoline derivatives provided by this invention, after protonation, can be used as photocatalysts to catalyze the oxidation of alcohols to ketones or carboxylic acids. Compared with common commercial photocatalysts, this type of catalyst has better stability, can be excited in the visible light range, has a high excited-state reduction potential, and can efficiently and selectively catalyze the oxidation of alcohols to the corresponding ketones or acids under air conditions with a low catalyst dosage. This invention avoids the use of strong oxidants and transition metal catalysts, is green and efficient, economical and practical, and clean and environmentally friendly, exhibiting significant advantages in catalytic activity. Detailed Implementation

[0098] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0099] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0100] This invention provides a novel photocatalyst based on a quinoline derivative and its application in the selective oxidation of alcohols. The preparation method of the quinoline derivative of this invention includes method 1, method 2, or method 3.

[0101] Method 1 includes the following steps: (1) Compound II reacts with an oxidizing agent to obtain NO oxide III of quinoline, with a yield of 71%-80%; the oxidizing agent is at least one of 3-chloroperoxybenzoic acid, H2O2, NaClO, and potassium peroxymonosulfonate; the solvent is at least one of dichloromethane, ethyl acetate, and 1,2-dichloroethane; (2) NO oxide III of quinoline reacts with a cyaniding reagent to obtain compound IV, with a yield of 60%-78%; the cyaniding reagent is trimethylsilane cyano (TMSCN); (3) Compound IV reacts with arylboronic acid to undergo a cross-coupling reaction to obtain the compound shown in Formula I, with a yield of 30%-96%; the arylboronic acid is substituted or unsubstituted phenylboronic acid; the substituted phenylboronic acid contains at least one electron-withdrawing group or electron-donating group; the electron-withdrawing group is at least one of halogen, cyano, and carbonyl; the electron-donating group is at least one of alkyl, alkoxy, and amino; preferably, the electron-withdrawing group is at least one of alkyl, alkoxy, and amino groups. When the group is a halogen, the halogen is fluorine, chlorine, bromine, or iodine; and / or, when the electron-withdrawing group is a carbonyl group, the carbonyl group contains 1-6 carbon atoms; and / or, when the electron-donating group is an alkyl group, the alkyl group is C1-C5 alkyl; and / or, when the electron-donating group is an alkoxy group, the alkoxy group contains 1-6 carbon atoms; and / or, when the electron-donating group is an amino group, the amino group is NR1R2, wherein R1 and R2 are each independently selected from H or C1-C3 alkyl groups. The catalyst is a complex of tetraphenylphosphine palladium (Pd(PPh3)4), palladium acetate (Pd(OAc)2), or palladium chloride (PdCl2) with a ligand, wherein the ligand is at least one of tri-n-butylphosphine (P(n-Bu)3), triphenylphosphine (PPh3), and tricyclohexylphosphine (PCy3); the alkaline reagent is at least one of K2CO3, Cs2CO3, Na2CO3, and CsF; and the solvent is a mixed solution of toluene, ethanol, and water.

[0102]

[0103] Method 2 includes the following steps: (1) Compound II is reacted with arylboronic acid to undergo a cross-coupling reaction to obtain compound V; the arylboronic acid is a substituted or unsubstituted phenylboronic acid; the substituted phenylboronic acid contains at least one electron-withdrawing group or an electron-donating group; the electron-withdrawing group is at least one of halogen, cyano, and carbonyl; the electron-donating group is at least one of alkyl, alkoxy, and amino; preferably, when the electron-withdrawing group is a halogen, the halogen is fluorine, chlorine, bromine, or iodine; when the electron-withdrawing group is a carbonyl, the carbonyl contains 1-6 carbon atoms; and / or, and / or, when the electron-donating group is an alkyl, the alkyl is C1-C5 alkyl; and / or, when the electron-donating group is an alkoxy, the alkoxy contains 1-6 carbon atoms; and / or, when the electron-donating group is an amino, the amino is NR1R2, wherein R1 and R2 are each independently selected from H or C1-C3 alkyl. The catalyst is a complex of palladium tetraphenylphosphine, or palladium acetate (Pd(OAc)2) or palladium chloride (PdCl2) with a ligand, wherein the ligand is at least one of tri-n-butylphosphine (P(n-Bu)3), triphenylphosphine (PPh3), and tricyclohexylphosphine (PCy3); the basic reagent is at least one of K2CO3, Cs2CO3, and Na2CO3; the solvent is a mixed solution of tetrahydrofuran, methanol, and water, with a yield of 57%-80%; (2) compound Compound V reacts with an oxidizing agent to give NO oxide VI of quinoline in a yield of 70%-85%; the oxidizing agent is at least one of 3-chloroperoxybenzoic acid, H2O2, NaClO, and potassium peroxymonosulfonate; the solvent is at least one of dichloromethane, ethyl acetate, and 1,2-dichloroethane; (3) NO oxide VI of quinoline reacts with a cyaniding reagent to give a compound as shown in Formula I in a yield of 30%-71%; the cyaniding reagent is trimethylsilane cyano (TMSCN).

[0104]

[0105] Method 3 includes the following steps: (1) Compound II reacts with an oxidizing agent to obtain NO oxide III of quinoline in a yield of 71%-80%; the oxidizing agent is at least one of 3-chloroperoxybenzoic acid, H2O2, NaClO, and potassium peroxymonosulfonate; the solvent is at least one of dichloromethane, ethyl acetate, and 1,2-dichloroethane; (2) NO oxide III of quinoline reacts with a cyaniding reagent to obtain compound IV in a yield of 60%-73%; the cyaniding reagent is trimethylsilane cyano (TMSCN).

[0106]

[0107] The carbonyl group includes, but is not limited to, ketones, aldehydes, carboxylic acids, esters, and amides.

[0108] The following compounds can be prepared using the above preparation method:

[0109]

[0110] The quinoline derivatives prepared above, after being protonated, can be used as photocatalysts. They exhibit good stability, can be excited in the visible light range, have high excited-state reduction potential, and are easy to synthesize and modify. Therefore, they have significant advantages in the oxidation of alcohols. They can achieve the catalytic oxidation of alcohols with high efficiency and selectivity under air conditions with low catalyst dosage. When the alcohol is a primary alcohol, it is oxidized to a carboxylic acid, and when the alcohol is a secondary alcohol, it is oxidized to a ketone.

[0111] The present invention will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed by the present invention.

[0112] Example 1

[0113] The reaction route shown below illustrates the preparation method of the quinoline derivative provided in this embodiment, which includes the following steps:

[0114]

[0115] (1) Weigh 20 mmol of 4-bromo-7-methoxyquinoline IIa and add it to a 500 mL three-necked flask, then add 120 mL of dichloromethane (DCM) to dissolve it; weigh 34 mmol of 3-chloroperoxybenzoic acid (85% purity) and add it to a 250 mL round-bottom flask, then add 100 mL of DCM to dissolve it; under ice-water bath conditions, slowly add the above DCM solution of 3-chloroperoxybenzoic acid to the DCM solution of 4-bromo-7-methoxyquinoline, restore to room temperature, stir for 20 h, and after the reaction is complete, use 5.6 mL of... The mixture was quenched with 6M KOH aqueous solution until no more bubbles were generated. The reaction mixture was transferred to a separatory funnel, and the aqueous phase was extracted three times with dichloromethane. The combined organic phases were washed once with saturated brine, dried over anhydrous magnesium sulfate for 30 minutes, filtered through diatomaceous earth, and the resulting solution was concentrated by rotary evaporation to obtain the crude product. The crude product was separated by silica gel column chromatography (eluting agents were ethyl acetate and methanol, volume ratio 20:1) to give 3.95 g of pale yellow solid IIIa. The yield of this step was 71%.

[0116] The IIIa prepared in this step was subjected to proton and carbon NMR spectra, and the results are shown below:

[0117] 1H NMR (400MHz, CDCl3) δ8.34(d,J=6.6Hz,1H),8.09(d,J=2.6Hz,1H),8.05(d,J=9.2Hz,1H),7.42(d,J=6.6Hz,1H),7.35(dd,J=9.2,2.5Hz,1H),4.02(s,3H).

[0118] 13 C NMR (101MHz, CDCl3) δ162.6,143.6,135.8,129.2,124.4,123.0,122.1,120.2,98.8,56.3.

[0119] (2) Weigh 14 mmol IIIa and add it to a 100 mL sealed tube. Under nitrogen protection, add 51.8 mmol of trimethylsilane cyano (TMSCN). No other solvent needs to be added. React at 140 °C for 6 h. After the reaction is complete, cool to room temperature and add 52 mL of 1 M K2CO3 solution to quench the reaction until no more bubbles are produced. Dissolve the reaction mixture in dichloromethane (DCM) and transfer it to a separatory funnel. Extract the organic phase three times with water. Collect the organic phase and wash it once with saturated brine. Dry it with anhydrous magnesium sulfate for 30 minutes. After filtration through diatomaceous earth, concentrate the resulting solution by rotary evaporation to obtain the crude product. Separate the crude product by silica gel column chromatography (eluent: petroleum ether and ethyl acetate, volume ratio 10:1) to obtain 2.69 g of white solid IVa, with a yield of 73%.

[0120] The IVa prepared in this step was subjected to proton and carbon NMR spectra, and the results are shown below:

[0121] 1 H NMR (500MHz, CDCl3) δ8.12(d,J=9.5Hz,1H),7.84(s,1H),7.44(d,J=2.3Hz,1H),7.42(dd,J=9.2,2.6Hz,1H),3.99(s,3H).

[0122] 13 C NMR (101MHz, CDCl3) δ162.6,150.4,134.6,133.4,127.9,125.0,124.3,124.0,116.5,107.7,56.0.

[0123] (3) Under nitrogen atmosphere, 1.4 mmol IVa, 1.5 mmol phenylboronic acid, 0.11 mmol tetraphenylphosphine palladium, 24 mL toluene, 6 mL ethanol, and 1.4 mL 2 M K2CO3 aqueous solution were added to a 100 mL three-necked flask and refluxed at 80 °C for 12 h. After the reaction was completed, the mixture was allowed to return to room temperature. The reaction solution was diluted with ethyl acetate (EA), filtered through diatomaceous earth, and the resulting solution was concentrated by rotary evaporation to obtain the product. The product was dissolved in dichloromethane (DCM) and transferred to a separatory funnel. The organic phase was extracted three times with water, and the organic phase was collected. The organic phase was washed once with saturated brine, dried over anhydrous magnesium sulfate for 30 minutes, filtered through diatomaceous earth, and the resulting solution was concentrated by rotary evaporation to obtain the crude product. The crude product was separated by silica gel column chromatography (eluent: petroleum ether and ethyl acetate, volume ratio 10:1) to obtain 340.1 mg of pale yellow solid Ia. The yield of this step was 96%.

[0124] The IIIa prepared in this step was subjected to proton and carbon NMR spectra, and the results are shown below:

[0125] 1 H NMR (400MHz, CDCl3) δ7.85 (d, J = 9.3Hz, 1H), 7.59-7.53 (m, 3H), 7.52 (s, 1H), 7.49 (dd ,J=10.1,2.7Hz,2H),7.46(d,J=1.8Hz,1H),7.28(dd,J=9.4,2.6Hz,1H),3.99(s,3H).

[0126] 13 C NMR (101MHz, CDCl3) δ161.7,150.8,150.1,136.5,133.4,129.4,129.2,128.9,127.1,123.0,122.7,121.8,117.8,107.6,55.8.

[0127] Example 2

[0128] The reaction route shown below illustrates the preparation method of the quinoline derivative provided in this embodiment, which includes the following steps:

[0129]

[0130] (1) IVa was prepared using the same method as in Example 1.

[0131] (3) Under nitrogen atmosphere, 2 mmol IVa, 4 mmol 1,3,5-trimethylbenzene-2-boric acid, 0.2 mmol tetraphenylphosphine palladium, 32 mL toluene, 8 mL ethanol, and 2.1 mL 2M Cs2CO3 aqueous solution were added to a 100 mL three-necked flask and refluxed at 80 °C for 18 h. After the reaction was completed, the mixture was allowed to return to room temperature. The reaction solution was diluted with ethyl acetate (EA), filtered through diatomaceous earth, and the resulting solution was concentrated by rotary evaporation to obtain the product. The product was dissolved in dichloromethane (DCM) and transferred to a separatory funnel. The organic phase was extracted three times with water, and the organic phase was collected. The organic phase was washed once with saturated brine, dried over anhydrous magnesium sulfate for 30 min, filtered through diatomaceous earth, and the resulting solution was concentrated by rotary evaporation to obtain the crude product. The crude product was separated by silica gel column chromatography (eluent: petroleum ether and ethyl acetate, volume ratio 10:1) to obtain 352.1 mg of pale yellow solid Ib. The yield of this step was 58%.

[0132] The Ib prepared in this step was subjected to proton and carbon NMR spectra, and the results are shown below:

[0133] 1 H NMR (400MHz, CDCl3) δ7.50 (s, 1H), 7.38 (s, 1H), 7.33 (d, J = 9.2Hz, 1H), 7.20 (dd,J=9.3,2.4Hz,1H),7.01(s,2H),3.98(s,3H),2.38(s,3H),1.85(s,6H).

[0134] 13 C NMR (101MHz, CDCl3) δ161.9,150.6,149.9,138.5,135.6,133.8,132.5,128.5,126.6,123.6,123.2,122.3,117.9,107.6,55.8,21.1,20.1.

[0135] Example 3

[0136] The reaction route shown below illustrates the preparation method of the quinoline derivative provided in this embodiment, which includes the following steps:

[0137]

[0138] (1) IVa was prepared using the same method as in Example 1.

[0139] (2) Under nitrogen atmosphere, 3.95 mmol IVa, 7.9 mmol 2,4-difluorophenylboronic acid, 0.32 mmol tetraphenylphosphine palladium, 50 mL toluene, 18 mL ethanol, and 5.9 mL 2M K2CO3 aqueous solution were added to a 250 mL three-necked flask and refluxed at 80 °C for 18 h. After the reaction was completed, the mixture was allowed to return to room temperature. The reaction solution was diluted with ethyl acetate (EA), filtered through diatomaceous earth, and the resulting solution was concentrated by rotary evaporation to obtain the product. The product was dissolved in dichloromethane (DCM) and transferred to a separatory funnel. The organic phase was extracted three times with water, and the organic phase was collected. The organic phase was washed once with saturated brine, dried over anhydrous magnesium sulfate for 30 min, filtered through diatomaceous earth, and the resulting solution was concentrated by rotary evaporation to obtain the crude product. The crude product was separated by silica gel column chromatography (eluent: petroleum ether and ethyl acetate, volume ratio 10:1) to obtain 891.2 mg of white solid Ic. The yield of this step was 76%.

[0140] The Ic prepared in this step was subjected to proton and carbon NMR spectra, and the results are shown below:

[0141] 1 H NMR (400MHz, CDCl3) δ7.59(dd,J=9.3,2.2Hz,1H),7.51(s,2H),7.37(td,J=8.3,6.3Hz,1H),7.30(dd,J=9.4,2.5Hz,1H),7.12-7.00(m,2H),3.99(s,3H).

[0142] 13 C NMR (101MHz, CDCl3) δ161.9, 165.3-157.9 (m), 150.6, 143.1, 133.4, 132.3 (dd, J = 9.7, 4.3Hz), 126.6 (d, J = 1.7Hz), 1 23.4,122.9,122.6,120.1(dd,J=15.7,4.0Hz),117.5,112.2(dd,J=21.5,3.8Hz),107.7,104.9(t,J=25.5Hz),55.8.

[0143] Example 4

[0144] The reaction route shown below illustrates the preparation method of the quinoline derivative provided in this embodiment, which includes the following steps:

[0145]

[0146] (1) Under nitrogen atmosphere, 5 mmol of 4-bromo-7-chloroquinoline IId, 5 mmol of phenylboronic acid, 0.4 mmol of palladium acetate, 2.4 mmol of triphenylphosphine, 20 mL of tetrahydrofuran (THF), 10 mL of methanol, and 5.3 mL of 2MK2CO3 aqueous solution were added to a 250 mL three-necked flask and refluxed at 75 °C for 2 days. After the reaction was completed, the mixture was allowed to return to room temperature. The reaction solution was diluted with ethyl acetate (EA), filtered through diatomaceous earth, and the resulting solution was concentrated by rotary evaporation to obtain the product. The product was dissolved in dichloromethane (DCM) and transferred to a separatory funnel. The organic phase was extracted three times with water, and the organic phase was collected. The organic phase was washed once with saturated brine, dried over anhydrous magnesium sulfate for 30 minutes, filtered through diatomaceous earth, and the resulting solution was concentrated by rotary evaporation to obtain the crude product. The crude product was separated by silica gel column chromatography (eluent: petroleum ether and ethyl acetate, volume ratio 10:1) to obtain 683.3 mg of pale yellow solid Vd. The yield of this step was 57%.

[0147] The Vd prepared in this step was subjected to proton and carbon NMR spectra, and the results are shown below:

[0148] 1 H NMR (400MHz, CDCl3) δ8.93(d,J=4.4Hz,1H),8.17(d,J=2.1Hz,1H),7.85(d,J=9.0Hz,1H),7.56 -7.49(m,3H),7.46(dd,J=7.3,2.0Hz,2H),7.43(dd,J=9.0,2.1Hz,1H),7.32(d,J=4.4Hz,1H).

[0149] 13 C NMR (101MHz, CDCl3) δ151.0,149.1,148.6,137.5,135.3,129.5,128.7,127.6,127.4,125.2,121.5.

[0150] (2) Weigh 2 mmol Vd into a 100 mL three-necked flask and dissolve it in 10 mL of dichloromethane (DCM); weigh 4 mmol 3-chloroperoxybenzoic acid (85% purity) into a 250 mL round-bottom flask and dissolve it in 25 mL of DCM; slowly add the DCM solution of 3-chloroperoxybenzoic acid to the DCM solution of Ve in an ice-water bath, restore to room temperature, stir for 20 h, and after the reaction is complete, use 0.66 mL of DCM solution to dissolve the remaining 3-chloroperoxybenzoic acid. Quenching with 6M KOH aqueous solution until no bubbles are generated in the system, the reaction mixture is transferred to a separatory funnel, the aqueous phase is extracted three times with dichloromethane, the organic phases are combined, the organic phase is washed once with saturated brine, dried over anhydrous magnesium sulfate for 30 minutes, filtered through diatomaceous earth, and the resulting solution is concentrated by rotary evaporation to obtain the crude product. The crude product is separated by silica gel column chromatography (eluent is petroleum ether and ethyl acetate, volume ratio 1:1) to obtain 436.2 mg of off-white VId crude product solid, the yield of this step is 85%.

[0151] (3) Weigh 1.67 mmol of crude VId product and add it to a 50 mL sealed tube. Under nitrogen protection, add 3.67 mmol of trimethylsilane cyano (TMSCN) without adding other solvents. React at 140 °C for 4 h. After the reaction is complete, cool to room temperature and add 3.7 mL of 1 M K2CO3 solution to quench the reaction until no more gas is produced. Dissolve the reaction mixture in dichloromethane (DCM) and transfer it to a separatory funnel. Extract the organic phase three times with water. Collect the organic phase, wash it once with saturated brine, dry it with anhydrous magnesium sulfate for 30 minutes, filter it with diatomaceous earth, and concentrate the resulting solution by rotary evaporation to obtain the crude product. Separate the crude product by silica gel column chromatography (eluent: petroleum ether and ethyl acetate, volume ratio 5:1) to obtain 313.0 mg of white solid Id. The yield of this step is 71%.

[0152] The Id prepared in this step was subjected to proton and carbon NMR spectra, and the results are shown below:

[0153] 1 H NMR (400MHz, CDCl3) δ8.19 (d, J = 2.2Hz, 1H), 7.92 (d, J = 9.0Hz, 1H), 7.63 (s, 1H), 7.61-7.54 (m, 4H), 7.51-7.44 (m, 2H).

[0154] 13 C NMR (101MHz, CDCl3) δ150.6,149.1,137.3,135.8,134.4,130.4,129.6,129.4,129.1,127.4,125.8,123.6,117.3.

[0155] Example 5

[0156] The reaction route shown below illustrates the preparation method of the quinoline derivative provided in this embodiment, which includes the following steps:

[0157]

[0158] (1) IVa was prepared using the same method as in Example 1.

[0159] (2) Under nitrogen atmosphere, 1 mmol IVa, 2 mmol 4-methoxyphenylboronic acid, 0.08 mmol tetraphenylphosphine palladium, 24 mL toluene, 6 mL ethanol, and 5.9 mL, 3 mmol K2CO3 aqueous solution were added to a 100 mL three-necked flask. The mixture was refluxed at 80 °C for 18 h. After the reaction was completed, the mixture was allowed to return to room temperature. The reaction solution was diluted with ethyl acetate (EA), filtered through diatomaceous earth, and the resulting solution was concentrated by rotary evaporation to obtain the product. The product was dissolved in dichloromethane (DCM) and transferred to a separatory funnel. The organic phase was extracted three times with water, and the organic phase was collected. The organic phase was washed once with saturated brine, dried over anhydrous magnesium sulfate for 30 min, filtered through diatomaceous earth, and the resulting solution was concentrated by rotary evaporation to obtain the crude product. The crude product was separated by silica gel column chromatography (eluent: petroleum ether and ethyl acetate, volume ratio 10:1) to obtain 164.1 mg of white solid Ie. The yield of this step was 57%.

[0160] The Ie prepared in this step was subjected to proton and carbon NMR spectra, and the results are shown below:

[0161] 1 H NMR (400MHz, CDCl3) δ7.9 (d, J = 9.3Hz, 1H), 7.5 (d, J = 4.2Hz, 2H), 7.4-7.4 (m, 2H), 7.3-7.3 (m, 1H), 7.1-7.0 (m, 2H), 4.0 (s, 3H), 3.9 (s, 3H).

[0162] 13 C NMR (101MHz, CDCl3) δ130.9,127.2,122.9,121.9,114.5,107.7,55.9,55.6.

[0163] Example 6

[0164] The reaction route shown below illustrates the preparation method of the quinoline derivative provided in this embodiment, which includes the following steps:

[0165]

[0166] (1) IVa was prepared using the same method as in Example 1.

[0167] (2) Under nitrogen atmosphere, 1 mmol IVa, 2 mmol 3-acetylphenylboronic acid, 0.08 mmol tetraphenylphosphine palladium, 24 mL toluene, 6 mL ethanol, and 5.9 mL 3 mmol K2CO3 aqueous solution were added to a 100 mL three-necked flask and refluxed at 80 °C for 18 h. After the reaction was completed, the mixture was allowed to return to room temperature. The reaction solution was diluted with ethyl acetate (EA), filtered through diatomaceous earth, and the resulting solution was concentrated by rotary evaporation to obtain the product. The product was dissolved in dichloromethane (DCM) and transferred to a separatory funnel. The organic phase was extracted three times with water, and the organic phase was collected. The organic phase was washed once with saturated brine, dried over anhydrous magnesium sulfate for 30 min, filtered through diatomaceous earth, and the resulting solution was concentrated by rotary evaporation to obtain the crude product. The crude product was separated by silica gel column chromatography (eluent: petroleum ether and ethyl acetate, volume ratio 10:1) to obtain 202.0 mg of white solid crude product If. The yield of this step was 67%.

[0168] The If prepared in this step was subjected to proton and carbon NMR spectra, and the results are shown below:

[0169] 1 H NMR (400MHz, CDCl3) δ8.1(s,1H),8.1(s,1H),7.8(d,J=9.3Hz,1H),7.7(d,J=4.6Hz,2H),7.5(s,2H),7.3(d,J=9.5Hz,1H),4.0(s,3H),2.7(s,3H).

[0170] 13 C NMR (101MHz, CDCl3) δ137.7,137.0,133.7,129.3,129.1,129.0,126.6,107.8,,55.9,26.8.

[0171] Example 7

[0172] The reaction route shown below illustrates the preparation method of the quinoline derivative provided in this embodiment, which includes the following steps:

[0173]

[0174] (1) IVa was prepared using the same method as in Example 1.

[0175] (2) Under nitrogen atmosphere, 1 mmol IVa, 2 mmol 4-cyanobenzoboric acid, 0.1 mmol tetraphenylphosphine palladium, 24 mL toluene, 6 mL ethanol, and 1.1 mL 2M K2CO3 aqueous solution were added to a 100 mL three-necked flask and refluxed at 80 °C for 18 h. After the reaction was completed, the mixture was allowed to return to room temperature. The reaction solution was diluted with ethyl acetate (EA), filtered through diatomaceous earth, and the resulting solution was concentrated by rotary evaporation to obtain the product. The product was dissolved in dichloromethane (DCM) and transferred to a separatory funnel. The organic phase was extracted three times with water, and the organic phase was collected. The organic phase was washed once with saturated brine, dried over anhydrous magnesium sulfate for 30 min, filtered through diatomaceous earth, and the resulting solution was concentrated by rotary evaporation to obtain the crude product. The crude product was separated by silica gel column chromatography (eluent: petroleum ether and ethyl acetate, volume ratio 10:1) to obtain 85.77 mg of white solid 1 g. The yield of this step was 30%.

[0176] The If prepared in this step was subjected to proton and carbon NMR spectra, and the results are shown below:

[0177] 1 H NMR (400MHz, CDCl3) δ7.87 (d, J=7.87Hz, 2H), 7.68 (dd, J=15.01, 9.29Hz, 2H), 7.61 (d, J=7.89Hz, 1H), 7.56 (d, J = 17.71Hz, 1H), 7.50 (s, 1H), 7.33 (dd, J = 9.38, 2.60Hz, 1H), 4.01 (d, J = 4.87Hz, 3H).

[0178] 13 C NMR (101MHz, CDCl3) δ162.0,147.7,141.1,133.5,132.7,132.5,130.3,130.2,128.1,126.2,123.8,121.4,118.1,107.9,55.9.

[0179] Example 8

[0180] The reaction route shown below illustrates the preparation method of the quinoline derivative provided in this embodiment, which includes the following steps:

[0181]

[0182] (1) Weigh 20 mmol of 4-bromo-6,7-dimethoxyquinoline IIb and add it to a 500 mL three-necked flask, then add 100 mL of dichloromethane (DCM) to dissolve it; weigh 40 mmol of 3-chloroperoxybenzoic acid (85% purity) and add it to a 250 mL round-bottom flask, then add 100 mL of DCM to dissolve it; under ice-water bath conditions, slowly add the above 3-chloroperoxybenzoic acid DCM solution dropwise to the 4-bromo-6,7-dimethoxyquinoline DCM solution, restore to room temperature, stir for 20 h, and after the reaction is complete, use 5.6 mL of... Quenching with 6M KOH aqueous solution until no more bubbles are generated in the system, the reaction mixture is transferred to a separatory funnel, the aqueous phase is extracted three times with dichloromethane, the combined organic phases are washed three times with saturated brine, dried over anhydrous magnesium sulfate for 30 minutes, filtered through diatomaceous earth, and the resulting solution is concentrated by rotary evaporation to obtain the crude product. The crude product is separated by silica gel column chromatography (eluting with ethyl acetate) to give 4.07 g of pale yellow solid IIIb, with a yield of 76%.

[0183] The IIIb prepared in this step was subjected to proton and carbon NMR spectra, and the results are shown below:

[0184] 1H NMR (400MHz, CDCl3) δ8.2(d,J=6.6Hz,1H),8.0(s,1H),7.4(d,J=6.6Hz,1H),7.2(s,1H),4.0(s,3H),4.0(s,3H).

[0185] 13 C NMR (101MHz, CDCl3) δ154.1,152.3,138.3,134.1,125.1,122.7,118.2,105.6,99.6,56.9,56.4.

[0186] (2) Weigh 15.2 mmol IIIb into a 250 mL sealed tube. Under nitrogen protection, add 60.0 mmol trimethylsilane cyano (TMSCN) without adding other solvents. React at 140 °C for 6 h. After the reaction is complete, cool to room temperature and add 52 mL of 1 M K2CO3 solution to quench the reaction until no more bubbles are produced. Dissolve the reaction mixture in dichloromethane (DCM) and transfer it to a separatory funnel. Extract the organic phase three times with water. Collect the organic phase, wash it once with saturated brine, dry it with anhydrous magnesium sulfate for 30 minutes, filter it with diatomaceous earth, and concentrate the resulting solution by rotary evaporation to obtain the crude product. Separate the crude product by silica gel column chromatography (eluent: petroleum ether and ethyl acetate, volume ratio 3:1) to obtain 3.42 g of white solid IVb, with a yield of 78%.

[0187] The IVb prepared in this step was subjected to proton and carbon NMR spectra, and the results are shown below:

[0188] 1H NMR (400MHz, CDCl3) δ7.8(s,1H),7.4(s,1H),7.4(s,1H),4.1(s,3H),4.1(s,3H).

[0189] 13C NMR (101MHz, CDCl3) δ154.5,132.0,125.7,125.3,108.4,104.1,56.7,56.6.

[0190] (3) Under nitrogen atmosphere, 1.0 mmol IVb, 1.1 mmol phenylboronic acid, 0.08 mmol tetraphenylphosphine palladium, 2.0 mmol K2CO3, 24 mL toluene, 6 mL ethanol, and 1.0 mL ultrapure water were added to a 100 mL three-necked flask and refluxed at 110 °C for 16 h. After the reaction was completed, the mixture was allowed to return to room temperature. The reaction solution was diluted with ethyl acetate (EA), filtered through diatomaceous earth, and the resulting solution was concentrated by rotary evaporation to obtain the product. The product was dissolved in dichloromethane (DCM) and transferred to a separatory funnel. The organic phase was extracted three times with water, and the organic phase was collected. The organic phase was washed once with saturated brine, dried over anhydrous magnesium sulfate for 30 minutes, filtered through diatomaceous earth, and the resulting solution was concentrated by rotary evaporation to obtain the crude product. The crude product was separated by silica gel column chromatography (eluent: petroleum ether and ethyl acetate, volume ratio 4:1) to obtain 228.0 mg of pale yellow solid Ih. The yield of this step was 79%.

[0191] The IIIa prepared in this step was subjected to proton and carbon NMR spectra, and the results are shown below:

[0192] 1H NMR (400MHz, CDCl3) δ7.6-7.5(m,7H),7.2(s,1H),4.1(s,3H),3.9(s,3H).

[0193] 13C NMR (101MHz, CDCl3) δ153.7,152.2,147.9,146.5,129.2,129.2,129.1,123.8,122.6,108.4,103.0,56.5,56.2.

[0194] Example 9

[0195] The reaction route shown below illustrates the preparation method of the quinoline derivative provided in this comparative example, which includes the following steps:

[0196]

[0197] (1) Weigh 4 mmol of 4-chloro-7-methoxyquinoline IIe and add it to a 250 mL three-necked flask, then add 40 mL of dichloromethane (DCM) to dissolve it; weigh 8 mmol of 3-chloroperoxybenzoic acid (85% purity) and add it to a 100 mL round-bottom flask, then add 40 mL of DCM to dissolve it; under ice-water bath conditions, slowly add the above 3-chloroperoxybenzoic acid DCM solution dropwise to the 4-chloro-7-methoxyquinoline DCM solution, and after restoring to room temperature, stir the reaction for 20 h. After the reaction is completed, use 1.6 mL of... Quenching with 6M KOH aqueous solution until no bubbles are generated in the system, the reaction mixture is transferred to a separatory funnel, the aqueous phase is extracted three times with dichloromethane, the combined organic phases are washed once with saturated brine, dried over anhydrous magnesium sulfate for 30 minutes, filtered through diatomaceous earth, and the resulting solution is concentrated by rotary evaporation to obtain the crude product. The crude product is separated by silica gel column chromatography (eluent: petroleum ether and ethyl acetate, volume ratio 1:1) to give 674.7 mg of pale yellow solid IIIe. The yield of this step is 80%.

[0198] The IIIe prepared in this step was subjected to proton and carbon NMR spectra, and the results are shown below:

[0199] 1 H NMR (400MHz, CDCl3) δ8.42(d,J=6.6Hz,1H),8.10(dd,J=5.8,3.3Hz,2H),7.37(dd,J=9.3,2.3Hz,1H),7.23(d,J=6.7Hz,1H),4.02(s,3H).

[0200] 13 C NMR (101MHz, CDCl3) δ162.6,143.6,135.8,130.3,126.6,123.1,122.7,118.6,98.9,56.2.

[0201] (2) Weigh 3.16 mmol of IIIe and add it to a 50 mL sealed tube. Under nitrogen protection, add 6.95 mmol of trimethylsilane cyano (TMSCN) without adding other solvents. React at 140 °C for 3 h. After the reaction is complete, cool to room temperature and add 7 mL of 1 M K2CO3 solution to quench the reaction until the system is stable. Dissolve the reaction mixture in dichloromethane (DCM) and transfer it to a separatory funnel. Extract the organic phase three times with water. Collect the organic phase and wash it once with saturated brine. Dry it with anhydrous magnesium sulfate for 30 minutes. After filtration through diatomaceous earth, concentrate the resulting solution by rotary evaporation to obtain the crude product. Separate the crude product by silica gel column chromatography (eluent: petroleum ether and ethyl acetate, volume ratio 10:1) to obtain 413.7 mg of white solid IVe. The yield of this step is 60%.

[0202] The IVe prepared in this step was subjected to proton and carbon NMR spectra, and the results are shown below:

[0203] 1 H NMR (400MHz, CDCl3) δ8.16(d,J=9.1Hz,1H),7.65(s,1H),7.46(d,J=2.5Hz,1H),7.43(dd,J=9.1,2.5Hz,1H),3.99(s,3H).

[0204] 13 C NMR (101MHz, CDCl3) δ162.6,150.9,143.7,133.5,125.3,124.1,122.6,121.5,116.8,107.7,56.0.

[0205] Experimental Example 1

[0206] The preparation method of protonated photocatalyst is as follows:

[0207] Taking Ic-H as an example: 236.8 mg Ic (0.8 mmol) and 382 μL HBF4 (2.4 mmol, 40% fluoroboric acid aqueous solution) were weighed and placed in a 50 mL round-bottom flask. Then, 10 mL of dichloromethane and 5 mL of acetonitrile were added as a mixed solvent. After dissolution, the mixture was stirred and reacted for 1 h. After the reaction was completed, the crude product was concentrated by rotary evaporation. The crude product was dried in a vacuum oven at 40 °C for 4 h to obtain 230.5 mL of bright yellow solid Ic-H, with a yield of 75%.

[0208] The bright yellow solid Ic-H prepared in this step was subjected to proton and carbon nuclear magnetic resonance (NMR) spectra, and the results are shown below:

[0209] 1 H NMR(400MHz,DMSO)δ7.90(d,J=1.7Hz,1H),7.66-7.55(m,3H),7.51(td,J=9.7,2 .3Hz,1H),7.41(dt,J=9.3,2.2Hz,1H),7.33(td,J=8.5,4.3Hz,1H),3.96(s,3H).

[0210] 13C NMR (101MHz, DMSO) δ 162.0, 161.5 (ddd, J = 407.6, 249.2, 12.3Hz), 150.2, 143.3, 133.5 (dd, J = 10.1, 4.3Hz), 133.3, 127. 2,123.8,123.3,122.8,120.3(dd,J=15.9,3.7Hz),118.0,112.9(dd,J=21.6,3.6Hz),108.0,105.1(t,J=26.2Hz),56.4

[0211] The specific reaction formula is as follows:

[0212]

[0213] The quinoline-derived organic small molecule photocatalysts prepared in the above examples were used to catalyze the selective oxidation of alcohols. Using 0.5 mmol VIIa as the reaction substrate, a protonated photocatalyst was used. The light source wavelength was 405 nm, the electric power was 10 W, and the reaction was carried out in air for 6 h to prepare VIIIa. The reaction effects of different photocatalysts were investigated, and the yield was analyzed by gas chromatography. The results are shown in Table 1.

[0214] The specific reaction formula is as follows:

[0215]

[0216] Table 1. Effects of different photocatalysts on oxidation reaction

[0217] catalyst Ia Ib Ic Id Ie If Ig Ih IVe Dawn Fluorenone Yield (%) 58 50 87 58 62 54 87 55 70 39 40

[0218] As can be seen from the table above, the catalyst prepared by this invention can effectively catalyze the selective oxidation of alcohols. Using Ic and Ig as photocatalysts, the highest yield of VIIa to VIIIa was achieved, at 87%.

[0219] Using 0.5 mmol VIIa as the reaction substrate and 0.5% fluorenone as the photocatalyst, with a light source wavelength of 405 nm and an electric power of 10 W, the reaction was carried out in air for 6 h to prepare VIIIa with a yield of 40%.

[0220] Using 0.5 mmol VIIa as the substrate and 0.5% eosin as the photocatalyst, with a light source wavelength of 405 nm and an electrical power of 10 W, the reaction was carried out in air for 6 h to prepare VIIIa with a yield of 39%.

[0221] Experimental Example 2

[0222] Using protonated Ic-H as a photocatalyst, selective oxidation reactions of alcohols with different types were tested.

[0223] VIIIb: Weigh 0.5 mmol VIIb and 0.0025 mmol Ic-H into a 20 mL quartz tube, then add 0.5 mL chlorobenzene and 0.5 mL acetonitrile as a mixed solvent. After dissolving, place the tube in a 395 nm, 10 W photoreactor and stir under air for 12 h. After the reaction is complete, transfer the product to a 50 mL pistol flask and concentrate by rotary evaporation to obtain the crude product. Separate the crude product by silica gel column chromatography (petroleum ether: ethyl acetate = 10:1) to obtain a pale yellow liquid VIIIb (GC yield 86%).

[0224] The specific reaction formula is as follows:

[0225]

[0226] VIIIc: Weigh 0.5 mmol VIIc and 0.0025 mmol Ic-H into a 20 mL quartz tube, then add 0.5 mL chlorobenzene and 0.5 mL acetonitrile as a mixed solvent. After dissolving, place the tube in a 395 nm, 10 W photoreactor and stir for 12 h under air. After the reaction is complete, transfer the product to a 50 mL pistol flask and concentrate by rotary evaporation to obtain the crude product. Separate the crude product by silica gel column chromatography (petroleum ether: ethyl acetate = 10:1) to obtain 74.7 mg of pale yellow liquid VIIIc, with a yield of 80%.

[0227] The pale yellow liquid VIIIc prepared in this step was subjected to proton and carbon NMR spectra, and the results are shown below:

[0228] 1 H NMR (400MHz, CDCl3) δ8.04 (d, J = 8.1Hz, 2H), 7.71 (d, J = 8.1Hz, 2H), 2.63 (s, 3H).

[0229] 13 C NMR (101MHz, CDCl3) δ196.9, 139.7, 134.4 (q, J = 32.6Hz, 1C), 128.6 (2C), 125.6 (q, J = 3.7Hz, 2C), 123.6 (q, J = 272.5Hz, 1C), 26.7.

[0230] The specific reaction formula is as follows:

[0231]

[0232] VIIId: Weigh 0.5 mmol of VIId and 0.0025 mmol of Ic-H into a 20 mL quartz tube, then add 0.5 mL of chlorobenzene and 0.5 mL of acetonitrile as a mixed solvent. After dissolving, place the tube in a 395 nm, 10 W photoreactor and stir for 12 h under air. After the reaction is complete, transfer the product to a 50 mL pistol flask and concentrate by rotary evaporation to obtain the crude product. Separate the crude product by silica gel column chromatography (petroleum ether: ethyl acetate = 5:1) to obtain 91.9 mg of white solid VIIId, with a yield of 94%.

[0233] The pale yellow liquid VIIId prepared in this step was subjected to proton and carbon NMR spectra, and the results are shown below:

[0234] 1 H NMR (400MHz, CDCl3) δ8.06-8.01(m,2H),7.71-7.67(m,2H),7.63(dd,J=7.0,1.6Hz,2H),7.51-7.44(m,2H),7.43-7.37(m,1H),2.64(s,3H).

[0235] 13 C NMR (101MHz, CDCl3) δ197.8,145.8,139.9,135.9,129.0,128.9,128.3,127.3,127.2,26.7.

[0236] The specific reaction formula is as follows:

[0237]

[0238] VIIIe: Weigh 0.5 mmol VIIe and 0.0025 mmol Ic-H into a 20 mL quartz tube, add 0.5 mL chlorobenzene and 0.5 mL acetonitrile as a mixed solvent, dissolve, and place in a 395 nm, 10 W photoreactor. Stir and react for 12 h under air. After the reaction is complete, transfer the product to a 50 mL pistol flask and concentrate by rotary evaporation to obtain the crude product. Separate the crude product by silica gel column chromatography (petroleum ether: ethyl acetate = 5:1) to obtain 54 mg of pale yellow liquid VIIIe, with a yield of 74%.

[0239] The pale yellow liquid VIIIe prepared in this step was subjected to proton and carbon NMR spectra, and the results are shown below:

[0240] 1 H NMR (400MHz, CDCl3) δ7.88 (dd, J=8.6, 1.4Hz, 2H), 7.46-7.38 (m, 2H), 2.58 (s, 3H).

[0241] 13 C NMR (101MHz, CDCl3) δ196.9,139.6,135.4,129.7,128.9,26.6.

[0242] The specific reaction formula is as follows:

[0243]

[0244] VIIIf: Weigh 0.5 mmol VIIf and 0.0025 mmol Ic-H into a 20 mL quartz tube, then add 0.5 mL chlorobenzene and 0.5 mL acetonitrile as a mixed solvent. After dissolving, place the tube in a 395 nm, 10 W photoreactor and stir for 12 h under air. After the reaction is complete, transfer the product to a 50 mL pistol flask and concentrate by rotary evaporation to obtain the crude product. Separate the crude product by silica gel column chromatography (petroleum ether: ethyl acetate = 5:1) to obtain 58.9 mg of white solid VIIIf, with a yield of 69%.

[0245] The white solid VIIIf prepared in this step was subjected to proton and carbon NMR spectra, and the results are shown below:

[0246] 1 H NMR (400MHz, CDCl3) δ8.46(s,1H),8.03(d,J=8.6Hz,1H),7.96(d,J=8.0Hz,1H),7.88(dd,J=8.3,5.6Hz,2H),7.64-7.51(m,2H),2.72(s,3H).

[0247] 13 C NMR (101MHz, CDCl3) δ198.2,135.6,134.5,132.5,130.2,129.6,128.5,128.4,127.8,126.8,123.9,26.7.

[0248] The specific reaction formula is as follows:

[0249]

[0250] VIIIg: 0.5 mmol VIIg and 0.0025 mmol Ic-H were placed in a 20 mL quartz tube, followed by the addition of 0.5 mL chlorobenzene and 0.5 mL acetonitrile as a mixed solvent. After dissolution, the mixture was placed in a 395 nm, 10 W photoreactor and stirred for 12 h under air. After the reaction was complete, the product was transferred to a 50 mL pistol flask and concentrated by rotary evaporation to obtain the crude product. The crude product was separated by silica gel column chromatography (petroleum ether: ethyl acetate = 6:1) to give 51.2 mg of white solid VIIIg, with a yield of 58%.

[0251] The white solid VIIIg prepared in this step was subjected to proton and carbon NMR spectra, and the results are shown below:

[0252] 1 H NMR (400MHz, CDCl3) δ7.90 (d, J = 8.1Hz, 2H), 7.47 (d, J = 8.1Hz, 2H), 2.58 (s, 3H), 1.34 (s, 9H).

[0253] 13 C NMR (101MHz, CDCl3) δ197.9,156.8,134.6,128.3(2C),125.5(2C),35.1,31.1(3C),26.6.

[0254] The specific reaction formula is as follows:

[0255]

[0256] VIIIh: Weigh 0.5 mmol of VIIh and 0.0025 mmol of Ic-H into a 20 mL quartz tube, then add 0.5 mL of chlorobenzene and 0.5 mL of acetonitrile as a mixed solvent. After dissolving, place the tube in a 395 nm, 10 W photoreactor and stir for 12 h under air. After the reaction is complete, transfer the product to a 50 mL pistol flask and concentrate by rotary evaporation to obtain the crude product. Separate the crude product by silica gel column chromatography (petroleum ether: ethyl acetate = 5:1) to obtain 34.8 mg of colorless liquid VIIIh, with a yield of 52%.

[0257] The colorless liquid VIIIh prepared in this step was subjected to proton and carbon NMR spectra, and the results are shown below:

[0258] 1 H NMR (400MHz, CDCl) 3 )δ7.95(d,J=8.3Hz,2H),7.35(d,J=8.0Hz,2H),2.67(s,3H),2.50(s,3H).

[0259] 13 C NMR (101MHz, CDCl) 3 )δ197.9,143.9,134.7,129.3,128.4,26.5,21.6.

[0260] The specific reaction formula is as follows:

[0261]

[0262] VIIIi: Weigh 0.5 mmol of VIIi and 0.0025 mmol of Ic-H into a 20 mL quartz tube, then add 0.5 mL of chlorobenzene and 0.5 mL of acetonitrile as a mixed solvent. After dissolving, place the tube in a 395 nm, 10 W photoreactor and stir for 12 h under air. After the reaction is complete, transfer the product to a 50 mL pistol flask and concentrate by rotary evaporation to obtain the crude product. Separate the crude product by silica gel column chromatography (petroleum ether: ethyl acetate = 5:1) to obtain 72 mg of white solid VIIIi, with a yield of 73%.

[0263] The colorless liquid VIIIi prepared in this step was subjected to proton and carbon NMR spectra, and the results are shown below:

[0264] 1 H NMR (400MHz, CDCl3) δ8.23(t,J=1.9Hz,1H),7.96(dt,J=7.7,1.4Hz,1H),7.85-7.78(m,1H),7.69-7.60(m,2H),7.60-7.37(m,4H),2.68(s,3H).

[0265] 13 C NMR (101MHz, CDCl3) δ146.4,141.5,141.1,129.0,128.8,127.4,127.2,126.3,124.3,124.3,77.2,70.5,25.3.

[0266] The specific reaction formula is as follows:

[0267]

[0268] VIIIj: Weigh 0.5 mmol of VIIj and 0.0025 mmol of Ic-H into a 20 mL quartz tube, then add 0.5 mL of chlorobenzene and 0.5 mL of acetonitrile as a mixed solvent. After dissolving, place the tube in a 395 nm, 10 W photoreactor and stir for 12 h under air. After the reaction is complete, transfer the product to a 50 mL pistol flask and concentrate by rotary evaporation to obtain the crude product. Separate the crude product by silica gel column chromatography (petroleum ether: tetrahydrofuran: acetic acid = 3:1:0.09) to obtain 48.7 mg of pale yellow solid VIIIj, with a yield of 49%.

[0269] The pale yellow solid VIIIj prepared in this step was subjected to proton and carbon NMR spectra, and the results are shown below:

[0270] 1 H NMR (400MHz, DMSO) δ8.02(d,J=8.0Hz,2H),7.80(d,J=8.0Hz,2H),7.73(d,J=7.7Hz,2H),7.50(t,J=7.5Hz,2H),7.42(t,J=7.3Hz,1H).

[0271] 13 C NMR (101MHz, DMSO) δ167.6,144.8,139.5,130.4(2C),130.1,129.6(4C),128.8,127.4,127.3.

[0272] The specific reaction formula is as follows:

[0273]

[0274] VIIIk: Weigh 0.5 mmol of VIIk and 0.0025 mmol of Ic-H into a 20 mL quartz tube, then add 0.5 mL of chlorobenzene and 0.5 mL of acetonitrile as a mixed solvent. After dissolving, place the tube in a 405 nm, 10 W photoreactor and stir for 12 h under air. After the reaction is complete, transfer the product to a 50 mL pistol flask and concentrate by rotary evaporation to obtain the crude product. Wash the crude product with ethyl acetate to obtain a pale yellow solid VIIIk, with a yield of 87%.

[0275] The pale yellow solid VIIIk prepared in this step was subjected to proton nuclear magnetic resonance spectroscopy, and the results are shown below:

[0276] 1 H NMR (400MHz, DMSO) δ8.04 (d, J = 8.5 Hz, 1H), 7.53 (d, J = 8.5 Hz, 1H).

[0277] The specific reaction formula is as follows:

[0278]

[0279] VIIIl: Weigh 0.5 mmol of VIIl and 0.015 mmol of Ic-H into a 20 mL quartz tube, then add 0.1 mL of dimethyl sulfoxide and 0.9 mL of acetonitrile as a mixed solvent. After dissolving, place the tube in a 405 nm, 10 W photoreactor and stir for 12 h under air. After the reaction is complete, transfer the product to a 50 mL pistol flask and concentrate by rotary evaporation to obtain the crude product. Separate the crude product by silica gel column chromatography (petroleum ether: ethyl acetate = 10:1) to obtain a colorless liquid VIIIl with a GC yield of 98%.

[0280] The colorless liquid VIIIl prepared in this step was subjected to 1H NMR spectroscopy, and the results are shown below:

[0281] 1 H NMR (400MHz, CDCl3) δ2.4-2.3(m,4H),1.9(tdd,J=7.21,5.16,2.15Hz,4H),1.5(p,J=5.84Hz,4H),1.4-1.3(m,2H).

[0282] The specific reaction formula is as follows:

[0283]

[0284] For unsubstituted 1-phenylethanol (VIIb), acetophenone (VIIIb) was obtained in 86% yield. For substituted acetophenones with electron-withdrawing functional groups, such as trifluoromethyl (VIIIc), para-phenyl (VIIId), and chloro-substituted (VIIIe), high isolated yields of 80%, 94%, and 74%, respectively were obtained; meta-phenyl (VIIIi) also showed a 73% yield. Naphthyl-1-ethanol (VIIIf), with a strongly conjugated benzyl ring structure, yielded a moderate isolated yield of 69%. The reaction was also tolerant to electron-donating functional groups, such as tert-butyl (VIIIg) and methyl (VIIIh), with yields of 58% and 52%, respectively. In addition to the oxidation of secondary benzyl alcohol, we also explored the oxidation of substituted benzyl alcohol, such as benzyl alcohol derivatives (VIIj, VIIk), to obtain substituted benzoic acids (VIIIj, VIIIk) in moderate to excellent yields of 49% and 87%, respectively. In this invention, different substituents have a significant impact on the properties of the compound. Compared with VIIIb, VIIId introduces the electron-withdrawing group phenyl, which changes the reactivity of the compound. The photocatalyst may have a better catalytic effect on the substrate with the electron-withdrawing group, thus causing the yield difference.

[0285] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A quinoline derivative, characterized in that, It has the following structure: 。 2. The application of the quinoline derivative of claim 1, after protonation with HBF4, as a photocatalyst in the catalytic oxidation of alcohols to ketones or carboxylic acids.

3. A method for oxidizing an alcohol, characterized in that, Includes the following steps: Under ultraviolet or visible light conditions, in the presence of photocatalysts and oxidants, alcohols are oxidized to produce ketones or carboxylic acids; The photocatalyst is the quinoline derivative of claim 1 protonated with HBF4.

4. The oxidation method according to claim 3, characterized in that, The oxidant is air or oxygen; And / or, the oxidation reaction is carried out in a photoreactor, the photoreactor having an electrical power of 5W-60W; And / or, the molar ratio of the alcohol to the photocatalyst is 10-200:1; And / or, the oxidation method further includes using a solvent, said solvent being at least one of ethyl acetate, dichloromethane, dichloroethane, dimethyl sulfoxide, chlorobenzene, acetonitrile, and water.

5. The oxidation method according to claim 4, characterized in that, The light wavelength is 360-500nm, and the reaction time is 2h-24h; And / or, the solvent is chlorobenzene and acetonitrile in a volume ratio of 0.1-10:1; And / or, if the alcohol is a primary alcohol, it is oxidized to a carboxylic acid, or if the alcohol is a secondary alcohol, it is oxidized to a ketone.

Images