Photoelectrosynthesis of ketones

Abstract

A photoelectric synthesis method for ketone compounds, the present invention relates to the field of organic photoelectric synthesis technology. The present invention solves the technical problem that existing reaction technologies are difficult to achieve in-situ activation of aromatic formic acid and direct coupling with hydrocarbons to prepare ketone compounds. The present invention continuously irradiates the reaction system and passes a constant current, uses carboxylic acid and hydrocarbons as reactants, forms chlorine radicals through an iron catalyst, and the chlorine radical intermediates extract hydrogen from the hydrocarbons to obtain an alkyl radical. At the same time, an acyl nickel compound intermediate is formed at the cathode, and then the intermediate captures the alkyl radical, and a reduction elimination process occurs to obtain a ketone product. This reaction uses the electrons provided by the current in the system as a cheap and clean oxidant, avoiding the use of an external oxidant, and the reaction operation is simple and the conditions are mild. The ketone compounds prepared by the present invention are used in the field of treatment of neurodegenerative diseases.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of organic photoelectric synthesis, and particularly relates to a method for preparing a ketone compound. BACKGROUND

[0002] Ketone compounds exist widely in drugs, natural products and agricultural products, and synthesis of the ketone compounds is an important topic in chemical research. In particular, ketone drugs are very effective in the treatment of neurodegenerative diseases, for example, Tolcapone is a clinical drug for treating Parkinson's disease.

[0003] Carboxylic acid compounds are important building blocks for constructing high-value-added organic molecules, and are also bulk chemicals that are easy to obtain. Some attractive existing synthesis routes of ketones are formed by a reaction of Grignard reagent and carboxylic acid and derivatives thereof, metal catalysis, photochemistry and peroxide oxidation. Although the corresponding ketone compounds can be effectively obtained, there are still some inherent shortcomings, such as the need to use an equivalent amount of oxidizing agent or reducing agent, harsh reaction conditions, cumbersome post-processing, the use of organic metal reagents to a certain extent limits the substrate universality and functional group diversity, and sometimes pre-activated carboxylic acid derivatives are needed, and the method is not simple and efficient. Therefore, it is still a topic to be studied to develop a green and simple synthesis method for directly synthesizing ketone compounds by directly activating carbon-hydrogen compounds and carboxylic acid. Therefore, it is particularly important to use simple carboxylic acid and carbon-hydrogen compounds to realize intermolecular coupling to synthesize ketones under mild conditions. SUMMARY

[0004] The present application solves the technical problem that the existing reaction technology cannot realize in-situ activation of aromatic carboxylic acid and direct coupling of carbon-hydrogen compounds to prepare ketone compounds, and provides a photoelectric synthesis method of ketone compounds. By means of photoelectric chemical synthesis strategy, the present application continuously performs light irradiation and passes in a constant current in the reaction system, uses simple carboxylic acid and carbon-hydrogen compounds as reactants, forms a chlorine free radical through a ligand to metal charge transfer process of an iron catalyst after being excited by light at an anode, the chlorine free radical intermediate performs hydrogen abstraction on the carbon-hydrogen compound to obtain an alkyl free radical, at the same time, oxidation addition process of a nickel catalyst and an acid anhydride generated by in-situ activation of carboxylic acid occurs at a cathode to form an acyl nickel compound intermediate, then the intermediate captures the alkyl free radical, and then reduction elimination process occurs to obtain a ketone product, and at the same time, the catalytic cycle of the nickel catalyst is completed through the change of valence.

[0005] A photoelectric synthesis method of a ketone compound is specifically performed according to the following steps:

[0006] I. placing an anode electrode and a cathode electrode in a quartz tube, adding a carboxylic acid compound, a hydrocarbon compound, diethyl dicarbonate, an iron catalyst, a nickel catalyst, a ligand, a base and LiCl in an inert gas atmosphere, and then adding an ultradry solvent, and sealing the system;

[0007] The carboxylic acid compound is benzoic acid, 4-chlorobenzoic acid, 4-fluorobenzoic acid, 4-methylbenzoic acid, 2-methylbenzoic acid, 3-phenylpropionic acid, cyclohexylcarboxylic acid or ketoprofen;

[0008] The ligand is 4,4'-di-tert-butyl-2,2'-bipyridine;

[0009] II. continuously irradiating the sealed system of step I under light irradiation with a wavelength of 390-395 nm, while continuously supplying a constant current and stirring to obtain a crude product;

[0010] III. removing the solvent from the crude product obtained in step II by reduced pressure distillation, and then separating and purifying the product by thin layer chromatography, to obtain the ketone compound.

[0011] Further, the hydrocarbon compound in step I is cyclopentane, cyclohexane, norbornane, tetraethylsilane, trimethylacetonitrile, toluene, 4-chlorotoluene, 4-cyanotoluene, 4-methyltoluene or cyclopentanone.

[0012] Further, the base in step I is sodium carbonate.

[0013] Further, the ultradry solvent in step I is ultradry acetonitrile.

[0014] Further, the iron catalyst in step I is ferrous chloride tetrahydrate.

[0015] Further, the nickel catalyst in step I is nickel perchlorate hexahydrate.

[0016] Further, the use amount ratio of the carboxylic acid compound to the ultradry solvent is 0.2 mmol:2 mL; the use amount ratio of the hydrocarbon compound to the ultradry solvent is 2 mmol:2 mL; the use amount ratio of diethyl dicarbonate to the ultradry solvent is 0.4 mmol:2 mL; the use amount ratio of the iron catalyst to the ultradry solvent is 0.02 mmol:2 mL; the use amount ratio of the nickel catalyst to the ultradry solvent is 0.03 mmol:2 mL; the use amount ratio of the ligand to the ultradry solvent is 0.02 mmol:2 mL; the use amount ratio of LiCl to the ultradry solvent is 0.4 mmol:2 mL; and the use amount ratio of the base to the ultradry solvent is 0.2 mmol:2 mL.

[0017] Further, the anode electrode in step I is a carbon felt electrode, and the cathode electrode is a carbon felt electrode.

[0018] Further, the constant current of step two is controlled to be 4mA, the temperature of the condensing pump connected to the photo-reactor is 16 DEG C, and the continuous power-on and light irradiation time is 12 hours; and the reaction progress is monitored by TLC.

[0019] Further, the solvent used in the thin layer chromatography separation and purification of step three is a mixed solvent of petroleum ether and ethyl acetate in a volume ratio of 30:1.

[0020] The reaction of the present application is as follows:

[0021]

[0022] The ketone compound prepared by the present application is an aryl ketone compound or an alkyl ketone compound.

[0023] The reaction mechanism of the present application is shown in the following figure: Figure 3

[0024] Initially, the process starts from Fe(III) complex (A), which generates its excited state (B) through photoexcitation, and the excited state [FeCl4] - Catalyst generates a ligand to metal charge transfer (LMCT) process to generate a chlorine radical, which will have a hydrogen abstraction reaction with an alkane to form an active carbon-centered radical intermediate (D), and [FeCl3] - At the anode, it is oxidized to recover [FeCl4] - The cycle is completed. At the same time, the Ni(II) catalyst precursor is reduced at the cathode to form a Ni(0) species (E), and the intermediate E is further oxidatively added with an anhydride to form an acyl Ni(II) species (F), and the carbon-centered radical is captured by the Ni(II) intermediate F to form a Ni(III) species (G), followed by a reductive elimination process to obtain the target ketone product, forming a Ni(I) species (H), which is reduced at the cathode to regenerate the active Ni(0) intermediate E to complete the cycle.

[0025] The present application has the following advantages:

[0026] Compared with the prior art, the present application synthesizes ketone compounds by a simple, green and efficient method, which has the following advantages:

[0027] (1) The electrons provided by the current in the reaction system are used as a cheap and clean oxidant, avoiding the use of an external oxidant, and the reaction operation is simple and the conditions are mild.

[0028] ​(2) The carboxylic acid compound, hydrocarbon compound, diethyl pyrocarbonate, iron catalyst, nickel catalyst, ligand, base, LiCl and super dry solvent used in the reaction system are simple, cheap and commercially available compounds, and the carbon felt electrode used is also a relatively cheap electrode sheet, so that the reaction system is simple and economical.

[0029] (3) The reaction system substrate has a wide application range and can be used to synthesize various aryl or alkyl ketone compounds. The reaction substrate can include polysubstituted carboxylic acid compounds, cycloalkane compounds, silane compounds, nitrile compounds and aryl or alkyl ketone compounds with different substituents.

[0030] The ketone compound prepared by the method can be used in the field of treatment of neurodegenerative diseases. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 is the ketone compound (4-1) obtained in Example 1 1 H NMR spectrum;

[0032] Figure 2 is the ketone compound (4-1) obtained in Example 1 13 C NMR spectrum;

[0033] Figure 3 is the reaction mechanism diagram of the present application. DETAILED DESCRIPTION

[0034] Embodiment I: The photoelectric synthesis method of the ketone compound is carried out according to the following steps:

[0035] I. Place an anode electrode and a cathode electrode in a quartz tube, add a carboxylic acid compound, a hydrocarbon compound, diethyl pyrocarbonate, an iron catalyst, a nickel catalyst, a ligand, a base and LiCl in an inert gas atmosphere, and then add a super dry solvent. The system is sealed.

[0036] The carboxylic acid compound is benzoic acid, 4-chlorobenzoic acid, 4-fluorobenzoic acid, 4-methylbenzoic acid, 2-methylbenzoic acid, 3-phenylpropionic acid, cyclohexyl carboxylic acid or ketoprofen;

[0037] The ligand is 4,4'-di-tert-butyl-2,2'-bipyridine;

[0038] II. The sealed system in step I is continuously irradiated under light with a wavelength of 390-395 nm, and a constant current is continuously supplied while stirring to obtain a crude product.

[0039] III. The crude product obtained in step II is subjected to reduced pressure distillation to remove the solvent, and then thin layer chromatography is used for separation and purification. The obtained product is the ketone compound.

[0040] Specific embodiment two: the difference between this embodiment and specific embodiment one is that the hydrocarbon in step one is cyclopentane, cyclohexane, norbornane, tetraethylsilane, trimethylacetonitrile, toluene, 4-chlorotoluene, 4-cyanotoluene, 4-methyltoluene or cyclopentanone. The others are the same as specific embodiment one.

[0041] Specific embodiment three: the difference between this embodiment and specific embodiment one or two is that the base in step one is sodium carbonate. The others are the same as specific embodiment one or two.

[0042] Specific embodiment four: the difference between this embodiment and one of specific embodiments one to three is that the super dry solvent in step one is super dry acetonitrile. The others are the same as one of specific embodiments one to three.

[0043] Specific embodiment five: the difference between this embodiment and one of specific embodiments one to four is that the iron catalyst in step one is ferrous chloride tetrahydrate. The others are the same as one of specific embodiments one to four.

[0044] Specific embodiment six: the difference between this embodiment and one of specific embodiments one to five is that the nickel catalyst in step one is nickel perchlorate hexahydrate. The others are the same as one of specific embodiments one to five.

[0045] Specific embodiment seven: the difference between this embodiment and one of specific embodiments one to six is that the ratio of the use amount of the carboxylic acid compound to the super dry solvent in step one is 0.2 mmol:2 mL; the ratio of the use amount of the hydrocarbon to the super dry solvent is 2 mmol:2 mL; the ratio of the use amount of diethyl pyrocarbonate to the super dry solvent is 0.4 mmol:2 mL; the ratio of the use amount of the iron catalyst to the super dry solvent is 0.02 mmol:2 mL; the ratio of the use amount of the nickel catalyst to the super dry solvent is 0.03 mmol:2 mL; the ratio of the use amount of the ligand to the super dry solvent is 0.02 mmol:2 mL; the ratio of the use amount of LiCl to the super dry solvent is 0.4 mmol:2 mL; the ratio of the use amount of the base to the super dry solvent is 0.2 mmol:2 mL. The others are the same as one of specific embodiments one to six.

[0046] Specific embodiment eight: the difference between this embodiment and one of specific embodiments one to seven is that the anode electrode in step one is a carbon felt electrode and the cathode electrode is a carbon felt electrode. The others are the same as one of specific embodiments one to seven.

[0047] Specific embodiment nine: the difference between this embodiment and one of specific embodiments one to eight is that the constant current in step two is 4 mA, the temperature of the condensation pump connected to the photochemical reactor is 16°C, and the continuous power supply and light irradiation time is 12 hours; TLC is used to monitor the reaction progress. The others are the same as one of specific embodiments one to eight.

[0048] Specific embodiment ten: different from one of the specific embodiments one to nine is that the solvent used in the thin layer chromatography separation and purification in step three is a mixed solvent of petroleum ether and ethyl acetate in a volume ratio of 30:1. The others are the same as one of the specific embodiments one to nine.

[0049] The content of the present application is not limited to the above-mentioned embodiments, and the combination of one or several specific embodiments can also achieve the purpose of the present application.

[0050] Example 1:

[0051] The photoelectric synthesis method of the ketone compound in this embodiment is specifically carried out according to the following steps:

[0052] I. Two carbon felt electrodes are placed in a 10 mL quartz tube, and 0.2 mmol of benzoic acid, 2 mmol of cyclohexane, 0.4 mmol of diethyl pyrocarbonate, 0.02 mmol of FeCl 2. 4H2O, 0.03 mmol of Ni(ClO4) 2. 6H2O, 0.04 mmol of 4,4'-di-tert-butyl-2,2'-bipyridine, 0.4 mmol of Na2CO3 and 0.4 mmol of LiCl, and 2 mL of ultradry acetonitrile solvent are added, and the system is sealed;

[0053] II. The sealed system in step I is continuously irradiated under 390-395 nm light, and a constant current of 4 mA is continuously supplied. The temperature of the condensation pump connected with the photochemical reactor is 16°C, and the stirring time is 12 h. The reaction progress is monitored by TLC, and the crude product is obtained;

[0054] III. The crude product obtained in step II is subjected to vacuum distillation to remove the solvent, and then thin layer chromatography separation and purification are carried out to obtain the product, which is identified as an aryl ketone compound (4-1) by nuclear magnetic hydrogen spectrum, carbon spectrum and mass spectrum, and its structural formula is:

[0055]

[0056] The purity is 99% and the yield is 66%. The nuclear magnetic data analysis is as follows: 1 H NMR (400 MHz, Chloroform-d) δ 7.94 (d, J = 7.8 Hz, 2H), 7.57-7.49 (m, 1H), 7.45 (t, J = 7.1 Hz, 2H), 3.26 (tt, J = 11.5, 3.3 Hz, 1H), 1.91-1.82 (m, 4H), 1.77-1.69 (m, 1H), 1.45-1.34 (m, 2H), 1.44-1.33 (m, 2H), 1.32-1.28 (m, 1H).

[0057] 13 C NMR (101 MHz, Chloroform-d) δ 204.01, 136.38, 132.81, 128.65, 45.67, 29.48, 26.03, 25.92.

[0058] Example 2:

[0059] The photoelectric synthesis method of the ketone compound is specifically carried out according to the following steps:

[0060] I. Two carbon felt electrodes are placed in a 10 mL quartz tube, and 0.2 mmol of 4-chlorobenzoic acid, 2 mmol of cyclohexane, 0.4 mmol of diethyl pyrocarbonate, 0.02 mmol of FeCl 2. 4H2O, 0.03 mmol of Ni(ClO4) 2. 6H2O, 0.04 mmol of 4,4'-di-tert-butyl-2,2'-bipyridine, 0.4 mmol of Na2CO3 and 0.4 mmol of LiCl, and 2 mL of ultradry acetonitrile solvent are added, and the system is sealed;

[0061] II. The sealed system in step I is continuously irradiated under 390-395 nm light, and a constant current of 4 mA is continuously supplied. The temperature of the condensation pump connected to the photochemical reactor is 16°C. The reaction is stirred for 12 h, and the progress of the reaction is monitored by TLC to obtain a crude product;

[0062] III. The crude product obtained in step II is subjected to vacuum distillation to remove the solvent, and then thin layer chromatography is used for separation and purification to obtain a product, which is identified as an aryl ketone compound (4-2) by nuclear magnetic hydrogen spectrum, carbon spectrum and mass spectrum, and the structural formula is:

[0063]

[0064] The purity is 99% and the yield is 50%. The nuclear magnetic data analysis is as follows: 1 H NMR (400 MHz, CDCl3) δ 7.92-7.85 (m, 2H), 7.46-7.40 (m, 2H), 3.20 (td, J = 11.1, 5.6 Hz, 1H), 1.89-1.82 (m, 4H), 1.80-1.68 (m, 1H), 1.55-1.33 (m, 5H).

[0065] 13 C NMR (101 MHz, CDCl3) δ 202.73, 139.19, 134.65, 129.78, 128.96, 45.69, 29.42, 25.96, 25.86.

[0066] Example 3

[0067] The photoelectric synthesis method of the ketone compound is carried out according to the following steps:

[0068] I. Two carbon felt electrodes are placed in a 10 mL quartz tube, and 0.2 mmol of 3-phenylpropionic acid, 2 mmol of cyclohexane, 0.4 mmol of diethyl pyrocarbonate, 0.02 mmol of FeCl 2. 4H2O, 0.03 mmol of Ni(ClO4) 2. 6H2O, 0.04 mmol of 4,4'-di-tert-butyl-2,2'-bipyridine, 0.4 mmol of Na2CO3 and 0.4 mmol of LiCl, and 2 mL of ultradry acetonitrile solvent are added, and the system is sealed;

[0069] II. The sealed system of step I is continuously irradiated under 390-395 nm light, and a constant current of 4 mA is continuously supplied. The temperature of the condensation pump connected to the photochemical reactor is 16°C. The reaction is stirred for 12 h, and the progress of the reaction is monitored by TLC. The crude product is obtained;

[0070] III. The crude product obtained in step II is subjected to vacuum distillation to remove the solvent, and then thin layer chromatography is used for separation and purification to obtain the product, which is identified as an alkyl ketone compound (5-1) by nuclear magnetic hydrogen spectrum, carbon spectrum and mass spectrum, and its structural formula is:

[0071]

[0072] The purity is 99% and the yield is 38%. The nuclear magnetic data analysis is as follows: 1 H NMR (400 MHz, CDCl3) δ 7.27 (dd, J = 8.7, 5.1 Hz, 2H), 7.23-7.13 (m, 3H), 2.88 (td, J = 7.7, 2.8 Hz, 2H), 2.76 (td, J = 7.5, 2.9 Hz, 2H), 2.31 (tt, J = 11.1, 3.3 Hz, 1H), 1.86-1.72 (m, 4H), 1.70-1.60 (m, 1H), 1.33-1.18 (m, 5H).

[0073] 13 C NMR (101 MHz, CDCl3) δ 203.66, 143.53, 133.83, 129.33, 128.46, 45.57, 29.54, 26.04, 25.95, 21.66.

[0074] Example 4

[0075] The photoelectric synthesis method of the ketone compound is specifically performed according to the following steps:

[0076] One, two carbon felt electrodes are placed in a 10 mL quartz tube, 0.2 mmol of cyclohexyl formic acid, 2 mmol of cyclohexane, 0.4 mmol of diethyl pyrocarbonate, 0.02 mmol of FeCl 2. 4H2O, 0.03 mmol of Ni(ClO4) 2. 6H2O, 0.04 mmol of 4,4'-di-tert-butyl-2,2'-bipyridine, 0.4 mmol of Na2CO3 and 0.4 mmol of LiCl, and 2 mL of ultradry acetonitrile solvent are added, and the system is sealed;

[0077] Two, the sealed system in step one is continuously irradiated under 390-395 nm light, while a constant current of 4 mA is continuously supplied, the temperature of the condensation pump connected with the photochemical reactor is 16°C, and stirring is performed for 12 h, and the reaction progress is monitored by TLC to obtain a crude product;

[0078] Three, the crude product obtained in step two is subjected to vacuum distillation to remove the solvent, and then thin layer chromatography is used for separation and purification to obtain a product, which is identified as an alkyl ketone compound (5-2) by nuclear magnetic hydrogen spectrum, carbon spectrum and mass spectrum, and the structural formula is:

[0079]

[0080] The purity is 99% and the yield is 32%; the nuclear magnetic data analysis is: 1 H NMR (400 MHz, Chloroform-d) δ 2.49 (t, J = 10.5 Hz, 2H), 1.79-1.76 (m, 8H), 1.69-1.66 (m, 2H), 1.38-1.16 (m, 10H).

[0081] 13 C NMR (101 MHz, Chloroform-d) δ δ 217.17, 49.20, 28.62, 25.91, 25.77.

[0082] Example 5:

[0083] The photoelectric synthesis method of the ketone compound is specifically performed according to the following steps:

[0084] One, two carbon felt electrodes are placed in a 10 mL quartz tube, 0.2 mmol of cyclohexyl formic acid, 2 mmol of cyclohexane, 0.4 mmol of diethyl pyrocarbonate, 0.02 mmol of FeCl 2. 4H2O, 0.03 mmol of Ni(ClO4)2. 6H2O, 0.04 mmol 4,4'-di-tert-butyl-2,2'-bipyridine, 0.4 mmol Na2CO3 and 0.4 mmol LiCl, and then 2 mL of ultrapure acetonitrile solvent was added, and the system was sealed;

[0085] II. The sealed system of step I was continuously irradiated under 390-395 nm light, while a constant current of 4 mA was continuously supplied, and the temperature of the condensing pump connected to the photochemical reactor was 16°C. The reaction was stirred for 12 h, and the progress of the reaction was monitored by TLC. The crude product was obtained.

[0086] III. The crude product obtained in step II was subjected to vacuum distillation to remove the solvent, and then thin layer chromatography was used for separation and purification to obtain the product, which was identified as an aryl ketone compound (4-3) by nuclear magnetic hydrogen spectrum, carbon spectrum and mass spectrum, and its structural formula was:

[0087]

[0088] The purity was 99%, and the yield was 52%. The nuclear magnetic data analysis was as follows: 1 H NMR (400 MHz, CDCl3) δ 8.04-7.87 (m, 2H), 7.60-7.49 (m, 1H), 7.49-7.39 (m, 2H), 3.72 (p, J = 7.9 Hz, 1H), 2.02-1.83 (m, 4H), 1.81-1.57 (m, 4H).

[0089] 13 C NMR (101 MHz, CDCl3) δ 202.91, 136.96, 132.79, 128.57, 128.53, 46.40, 30.03, 26.38.

[0090] Example 6:

[0091] The photoelectric synthesis method of the ketone compound in this example was carried out according to the following steps:

[0092] I. Two carbon felt electrodes were placed in a 10 mL quartz tube, and 0.2 mmol benzoic acid, 0.4 mmol norbornane, 0.4 mmol diethyl pyrocarbonate, 0.02 mmol FeCl 2. 4H2O, 0.03 mmol Ni(ClO4) 2. 6H2O, 0.04 mmol 4,4'-di-tert-butyl-2,2'-bipyridine, 0.4 mmol Na2CO3 and 0.4 mmol LiCl, and then 2 mL of ultrapure acetonitrile solvent was added, and the system was sealed;

[0093] II. The closed system of step I was continuously irradiated at 390-395 nm, while a constant current of 4 mA was continuously supplied, and the temperature of the condenser pump connected to the photochemical reactor was 16°C. The reaction was stirred for 12 h, and the progress of the reaction was monitored by TLC. The crude product was obtained;

[0094] III. The crude product obtained in step II was subjected to vacuum distillation to remove the solvent, and then was separated and purified by thin layer chromatography. The product was identified as an aryl ketone compound (4-4) by nuclear magnetic hydrogen spectrum, carbon spectrum and mass spectrum, and its structural formula was:

[0095]

[0096] The purity was 99%, and the yield was 36%. The nuclear magnetic data analysis was as follows: 1 H NMR (400 MHz, CDCl3) δ 7.99-7.94 (m, 2H), 7.57-7.51 (m, 1H), 7.47-7.43 (m, 2H), 3.22 (dd, J = 9.0, 5.5 Hz, 1H), 2.53-2.52 (m, 1H), 2.39-2.32 (m, 1H), 2.06-1.99 (m, 1H), 1.68-1.54 (m, 2H), 1.52-1.38 (m, 3H), 1.35-1.26 (m, 1H), 1.19-1.11 (m, 1H).

[0097] 13 C NMR (101 MHz, CDCl3) δ 201.48, 136.61, 132.71, 128.55, 128.53, 77.31, 49.56, 41.07, 36.34, 36.25, 33.72, 29.81, 29.09.

[0098] Example 7:

[0099] The photoelectric synthesis method of the ketone compound in this example was specifically performed according to the following steps:

[0100] I. Two carbon felt electrodes were placed in a 10 mL quartz tube, and 0.2 mmol of 3-phenylpropionic acid, 2 mmol of p-chlorotoluene, 0.4 mmol of diethyl pyrocarbonate, 0.02 mmol of FeCl3, 0.02 mmol of FeCl2, 0.04 mmol of 4,4′-dibenzyl-2,2′-bipyridine, 0.4 mmol of Na2CO3 and 0.4 mmol of LiCl were added under an inert gas atmosphere, and then 2 mL of ultradry acetonitrile solvent was added. The system was closed. 2. 4H2O, 0.03 mmol of Ni(ClO4) 2. 6H2O, 0.04 mmol of 4,4′-dibenzyl-2,2′-bipyridine, 0.4 mmol of Na2CO3 and 0.4 mmol of LiCl, and then 2 mL of ultradry acetonitrile solvent was added. The system was closed.

[0101] II. The closed system of step I was continuously irradiated at 390-395 nm, while a constant current of 4 mA was continuously supplied, and the temperature of the condenser pump connected to the photochemical reactor was 16°C. The stirring was continued for 12 h, and the progress of the reaction was monitored by TLC. The crude product was obtained;

[0102] III. The solvent of the crude product obtained in step II was removed by vacuum distillation, and the product was separated and purified by thin layer chromatography. The compound (5-3) was identified as an alkyl ketone compound by nuclear magnetic hydrogen spectrum, carbon spectrum and mass spectrum, and its structural formula was:

[0103]

[0104] The purity was 99%, and the yield was 45%. The nuclear magnetic data analysis was as follows: 1 H NMR (400 MHz, CDCl3) δ 7.27 (dd, J = 8.1, 6.3 Hz, 4H), 7.24-7.18 (m, 1H), 7.14 (d, J = 7.5 Hz, 2H), 7.08 (d, J = 8.0 Hz, 2H), 3.63 (s, 2H), 2.89 (t, J = 7.4 Hz, 2H), 2.78 (t, J = 7.4 Hz, 2H).

[0105] 13 C NMR (101 MHz, CDCl3) δ 206.94, 140.83, 133.07, 132.50, 130.86, 128.92, 128.61, 128.42, 126.28, 49.54, 43.74, 29.84.

[0106] Example 8:

[0107] The photoelectric synthesis method of the ketone compound in this example was specifically performed according to the following steps:

[0108] I. Two carbon felt electrodes were placed in a 10 mL quartz tube, and 0.2 mmol of 3-phenylpropionic acid, 2 mmol of chloro neopentane, 0.4 mmol of diethyl pyrocarbonate, 0.02 mmol of FeCl 2. 4H2O, 0.03 mmol of Ni (ClO4) 2. 6H2O, 0.04 mmol of 4,4'-di-tert-butyl-2,2'-bipyridine, 0.4 mmol of Na2CO3 and 0.4 mmol of LiCl were added, and 2 mL of ultradry acetonitrile solvent was added. The system was closed;

[0109] 2. The closed system in step 1 was continuously irradiated under 390-395 nm light while continuously passing a 4 mA constant current. The temperature of the condensation pump connected to the photoreactor was set at 16°C. The reaction was stirred for 12 h and the reaction progress was monitored by TLC to obtain a crude product.

[0110] 3. The crude product obtained in step 2 was subjected to reduced pressure distillation to remove the solvent, and then separated and purified by thin layer chromatography to obtain a product, which was identified as a ketone compound (5-4) by nuclear magnetic resonance spectroscopy, carbon spectrum and mass spectrometry, and its structural formula is:

[0111]

[0112] The purity is 99% and the yield is 35%. The NMR data analysis is as follows: 1 H NMR (400MHz, CDCl3) δ7.29-7.25(m,2H),7.20-7.16(m,3H),3.53(s,2H),2.87(t,J=7.6Hz,2H),2.72(t,J=7.6Hz,2H),2.44(s,2H),1.06(s,6H).

[0113] 13 C NMR (101MHz, CDCl3) δ209.02,141.07,128.57,128.41,126.18,54.63,49.79,46.07,35.45,29.73,25.69.

[0114] Example 9:

[0115] This embodiment provides a photoelectric synthesis method of ketone compounds, which is specifically carried out according to the following steps:

[0116] First, place two carbon felt electrodes in a 10 mL quartz tube and add 0.2 mmol ketoprofen, 2 mmol cyclohexane, 0.4 mmol diethyl pyrocarbonate, and 0.02 mmol FeCl in an inert gas atmosphere. 2. 4H2O, 0.03mmol Ni(ClO4) 2. 6H2O, 0.04mmol 4,4′-di-tert-butyl-2,2′bipyridine, 0.4mmol Na2CO3 and 0.4mmol LiCl, and then 2mL of ultra-dry acetonitrile solvent were added, and the system was sealed;

[0117] 2. The closed system in step 1 was continuously irradiated under 390-395 nm light while continuously passing a 4 mA constant current. The temperature of the condensation pump connected to the photoreactor was set at 16°C. The reaction was stirred for 12 h and the reaction progress was monitored by TLC to obtain a crude product.

[0118] III. The crude product obtained in step II was subjected to vacuum distillation to remove the solvent, and then was separated and purified by thin layer chromatography to obtain a product, which was identified as a ketone compound (5-5) by nuclear magnetic hydrogen spectrum, carbon spectrum and mass spectrum, and its structural formula is:

[0119]

[0120] The purity is 99%, and the yield is 30%; and the nuclear magnetic data analysis is as follows: 1 H NMR (400 MHz, CDCl3) δ 7.82-7.77 (m, 2H), 7.70-7.65 (m, 2H), 7.61 (t, J = 7.4 Hz, 1H), 7.53-7.40 (m, 4H), 4.01 (q, J = 6.9 Hz, 1H), 2.50-2.39 (m, 1H), 1.86-1.84 (m, 1H), 1.80-1.73 (m, 1H), 1.70-1.67 (m, 2H), 1.55-1.48 (m, 1H), 1.40 (d, J = 7.0 Hz, 3H), 1.35-1.23 (m, 3H), 1.18-1.11 (m, 2H).

[0121] 13 C NMR (101 MHz, CDCl3) δ 213.48, 196.68, 141.11, 138.13, 137.53, 132.67, 131.84, 130.15, 129.74, 128.99, 128.83, 128.41, 50.83, 49.80, 29.35, 28.36, 25.88, 25.77, 25.37, 18.36.

[0122] The above-described embodiments are only a preferred scheme of the present application, and do not limit the present application in any form. Other variants and modifications can be made without departing from the technical scheme recited in the claims.

Claims

1. A photoelectric synthesis method of ketone compounds, characterized in that The method is specifically carried out in the following steps:

1. Place an anode electrode and a cathode electrode in a quartz tube, add a carboxylic acid compound, a hydrocarbon compound, diethyl pyrocarbonate, an iron catalyst, a nickel catalyst, a ligand, a base, and LiCl under an inert gas atmosphere, then add an ultra-dry solvent, and seal the system; The ligand is 4,4'-di-tert-butyl-2,2'-bipyridine; 2. Continuously irradiate the closed system in step 1 under light at a wavelength of 390-395 nm while continuously passing a constant current and stirring to obtain a crude product; 3. The crude product obtained in step 2 is subjected to reduced pressure distillation to remove the solvent, and then separated and purified by thin layer chromatography to obtain the ketone compound; The hydrocarbon compound in step 1 is cyclopentane, cyclohexane, norbornane, trimethylacetonitrile, toluene, 4-chlorotoluene, 4-cyanotoluene, 4-methyltoluene or cyclopentanone; The iron catalyst in step 1 is ferrous chloride tetrahydrate; The nickel catalyst in step 1 is nickel perchlorate hexahydrate; Step 2: Control the constant current to 4 mA; The general reaction formula of step 2 is: ； Chemical formula (1) and chemical formula (2) are carboxylic acid compounds, and chemical formula (3) is a hydrocarbon compound; The carboxylic acid compound is benzoic acid, 4-chlorobenzoic acid, 4-fluorobenzoic acid, 4-methylbenzoic acid, 2-methylbenzoic acid, 3-phenylpropionic acid, cyclohexanecarboxylic acid or ketoprofen.

2. The photoelectric synthesis method of ketone compounds according to claim 1, characterized in that The base in step 1 is sodium carbonate.

3. The photoelectric synthesis method of ketone compounds according to claim 1, characterized in that The ultra-dry solvent in step 1 is ultra-dry acetonitrile.

4. The photoelectric synthesis method of ketone compounds according to claim 1, characterized in that The amount ratio of the carboxylic acid compound to the ultra-dry solvent in step 1 is 0.2 mmol: 2 mL; the amount ratio of the hydrocarbon to the ultra-dry solvent is 2 mmol: 2 mL; the amount ratio of diethyl pyrocarbonate to the ultra-dry solvent is 0.4 mmol: 2 mL; the amount ratio of the iron catalyst to the ultra-dry solvent is 0.02 mmol: 2 mL; the amount ratio of the nickel catalyst to the ultra-dry solvent is 0.03 mmol: 2mL; the amount ratio of the ligand to the ultra-dry solvent is 0.02 mmol: 2 mL; the amount ratio of LiCl to the ultra-dry solvent is 0.4 mmol: 2 mL; and the amount ratio of the base to the ultra-dry solvent is 0.2mmol: 2 mL.

5. The photoelectric synthesis method of ketone compounds according to claim 1, characterized in that In step 1, the anode electrode is a carbon felt electrode, and the cathode electrode is a carbon felt electrode.

6. The photoelectric synthesis method of ketone compounds according to claim 1, characterized in that Step 2: Control the temperature of the condensation pump connected to the photoreactor to 16°C, and continuously power on and illuminate for 12 hours; monitor the reaction progress using TLC.

7. The photoelectric synthesis method of ketone compounds according to claim 1, characterized in that The solvent used for the thin layer chromatography separation and purification in step 3 is a mixed solvent of petroleum ether and ethyl acetate in a volume ratio of 30:1.

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