Microwave-assisted preparation method of alpha-carbonyl fluoride

Abstract

The invention discloses a microwave-assisted preparation method of alpha-carbonyl fluoride, and relates to the field of preparation of related products of pharmacy, agriculture, material science and the like, in particular to a preparation method for introducing fluorine atoms to the alpha position of alpha-carbonyl bromide and preparing an alpha-carbonyl fluorine compound. According to the alpha-carbonyl fluorine compound disclosed by the invention, a target product can be rapidly obtained in a microwave synthesizer at a high yield under normal pressure, the preparation method of the alpha-carbonyl fluorine compound is simple, the yield is excellent, and a new thought is provided for fluorination reaction.

Description

Technical Field

[0001] This invention belongs to the field of pharmaceutical, materials science, and agricultural product preparation technology, specifically relating to a microwave-assisted method for preparing α-carbonyl fluorides. Background Technology

[0002] In the pharmaceutical field, organofluorine compounds can treat conditions including cancer, hyperlipidemia, hyperglycemia, and depression. Introducing fluorine atoms or fluorine-containing groups at specific positions in organic molecules can alter their physiological activity, often used to improve the bioactivity and stability of drugs. In the field of pesticides for insect control and weeding, fluorine compounds exhibit advantages such as high activity, low toxicity, and environmental friendliness, making them a key area of ​​development in the global pesticide industry. Currently, hundreds of fluorine-containing insecticides, fungicides, herbicides, and plant growth regulators have been developed and applied. Since 2019, the development of 5G has driven the development of new fluoropolymer materials. Fluoropolymers possess numerous advantages over conventional polymers due to the low polarizability, strong electronegativity, and small van der Waals radius of fluorine atoms. These advantages include excellent heat resistance, chemical corrosion resistance, weather resistance, solvent resistance, low flammability, high light transmittance, and low friction. Based on these superior properties, fluoropolymers play a crucial role not only in the transformation and upgrading of traditional industries but also in strategic emerging fields such as new energy and energy conservation and environmental protection. There are several practical examples of methods for introducing fluorine atoms into molecules. Literature (Chemical Communications, 2016, vol. 52) reports the use of pyridine, tetrabutylammonium fluoride, 1,4-dioxane, and water at 80°C for 24 hours, yielding a product (II) similar to that of the present invention with a yield of 89%. Literature (Journal of Fluorine Chemistry, 2016, vol. 181) reports the use of pyrrolidine-onium bis(fluorosulfonyl)imide, tetrahydrofuran, under inert gas protection, reflux, and a reaction time of 24 hours, yielding a product (II) similar to that of the present invention with a yield of 90%. Literature (Organic Letters, 2021, vol. 23) reports the use of potassium fluoride, a nickel catalyst containing heavy metals, water, tert-butanol, and a reaction time of 90°C for 4 hours, yielding a product (II) similar to that of the present invention with a yield of 92%. The aforementioned methods suffer from drawbacks such as long reaction times, complex catalysts, and limited applicability. Therefore, a new method is needed that is faster, has higher yields, simpler catalytic systems, and wider applicability. Currently, systematic research is lacking on a green, efficient, and rapid method for introducing fluorine atoms into molecules using inorganic fluoride CsF as a fluorine source under microwave conditions. Summary of the Invention

[0003] The main objective of this invention is to provide a microwave-assisted method for preparing α-carbonyl fluorides, which can effectively solve the problems in the background art.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] A microwave-assisted method for preparing α-carbonyl fluorides involves mixing an α-carbonyl bromide compound with CsF, 18-crown ether-6, and PEG200, and then reacting the mixture in a microwave reactor at a specific power and temperature to obtain an α-carbonyl fluoride compound in yield of 65-95%. The structural formula I of the α-carbonyl fluoride compound is as follows:

[0006]

[0007] Furthermore, the compound shown in Formula I is selected from any one of the structures shown in Formulas II to V below, with the specific structural formulas as follows: II: 2-fluoroarylacetaldehyde (ketone):

[0008]

[0009] III: 2-Fluoro-2-arylacetone:

[0010]

[0011] IV: N-aryl-2-fluoropropionamide:

[0012]

[0013] V: N-aryl-2-fluorophenylacetamide:

[0014]

[0015] In II, R3 = H, Cl, Br; R4 = H, CH3; in III, R5 = H, CH3O, CH3CH2; R6 = H, Cl, F; in IV, R7 = Cl, CH3O; and in V, R8 = H, Cl, CH3O.

[0016] Furthermore, the microwave power range is 60-160W.

[0017] Furthermore, the temperature range is 100℃-150℃.

[0018] Furthermore, the reaction time is 15-20 minutes.

[0019] Furthermore, compound I was prepared using compound VI, namely α-carbonyl bromide, as a starting material.

[0020]

[0021] Furthermore, the preparation method of compound II is as follows: α-carbonyl bromide and cesium fluoride are reacted at 105 °C with PEG200 and 18-crown ether-6 under normal pressure at 80 W microwave for 15 min. After the reaction is completed, the temperature is gradually reduced to room temperature, a small amount of water is added to quench the reaction, and the mixture is extracted with ethyl acetate and saturated brine. The organic phase is concentrated and purified by column chromatography with a volume ratio of n-hexane:ethyl acetate = 20:1 to obtain a yellow oily liquid with a yield of 85-93%.

[0022] Furthermore, the preparation method of compound III is as follows: 110 °C, PEG200, 18-crown ether-6, α-carbonyl bromide and cesium fluoride were reacted under ambient pressure with microwave at 80 W for 15 min. After the reaction was completed, the temperature was gradually reduced to room temperature, a small amount of water was added to quench the reaction, ethyl acetate and saturated brine were used for extraction, the organic phase was concentrated, and purified by column chromatography with a volume ratio of n-hexane:ethyl acetate = 20:1 to obtain a yellow oily liquid with a yield of 68-78%.

[0023] Furthermore, the preparation method of compound IV is as follows: α-carbonyl bromide and cesium fluoride are reacted at 105 °C with PEG200 and 18-crown ether-6 under normal pressure at 80 W microwave for 15 min. After the reaction is completed, the temperature is gradually reduced to room temperature. A small amount of water is added to quench the reaction. The mixture is extracted with ethyl acetate and saturated brine, the organic phase is concentrated, and purified by column chromatography with a volume ratio of n-hexane:ethyl acetate = 7:1 to obtain a white solid with a yield of 75-83%.

[0024] Further, the preparation method of compound V is as follows: α-carbonyl bromide and cesium fluoride were reacted at 105℃, PEG200, and 18-crown ether-6 under normal pressure at 80W microwave for 15 min. After the reaction was completed, the temperature was gradually reduced to room temperature. A small amount of water was added to quench the reaction. The mixture was extracted with ethyl acetate and saturated brine, and the organic phase was concentrated. The organic phase was purified by column chromatography with a volume ratio of n-hexane:ethyl acetate of 7:1 to obtain a yellow oily liquid with a yield of 70-78%.

[0025] The principle of this invention:

[0026] This invention utilizes the property of microwaves to change the dipole moment of molecules, causing the OH groups in the PEG200 reagent to be adsorbed and encapsulated with cesium ions by microwaves, and causing 18-crown ether-6 to encapsulate fluoride ions, thereby serving as a stable phase transfer catalyst to prepare new α-carbonyl fluorides.

[0027] Compared with the prior art, the present invention has the following beneficial effects.

[0028] 1) This invention is the first to prepare a variety of novel α-carbonyl fluorides using microwave catalysis.

[0029] 2) The preparation method of the present invention is simple, the reaction is rapid, and the post-processing is simple.

[0030] 3) This invention has wide applicability, high yield, and excellent practical value. Attached Figure Description

[0031] Figure 1 This describes the reaction process for synthesizing compound I from compound IV of the present invention;

[0032] Figure 2 The molecular structural formula of compound I of this invention is shown below;

[0033] Figure 3 The molecular structural formula of compound II of this invention is shown below;

[0034] Figure 4 The molecular structural formula of compound III of this invention is shown below;

[0035] Figure 5 The molecular structural formula of compound IV of this invention is shown below;

[0036] Figure 6 The molecular structural formula of compound V of this invention is shown below. Detailed Implementation

[0037] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0038] Example

[0039] Specific Implementation Method 1: The structure I of the α-carbonyl fluorinated substance in this implementation method is as follows:

[0040]

[0041] In specific implementation method two, the compound prepared in this implementation method is selected from any one of the structures shown in formulas II to V below, and the specific molecular structure is as follows:

[0042] II: 2-Fluoroacetaldehyde (ketone):

[0043]

[0044] III: 2-Fluoro-2-arylacetone:

[0045]

[0046] IV: N-aryl-2-fluoropropionamide:

[0047]

[0048] V: N-aryl-2-fluorophenylacetamide:

[0049]

[0050] In II, R3 = H, Cl, Br; R4 = H, CH3; in III, R5 = H, CH3O, CH3CH2; R6 = H, Cl, F; in IV, R7 = Cl, CH3O; and in V, R8 = H, Cl, CH3O.

[0051] In specific implementation method three, the preparation method of 2-fluoroarylacetaldehyde (ketone) II prepared in this embodiment is as follows: at 105°C, in a PEG200, 18-crown ether-6 system, 2-bromo-acetophenone and cesium fluoride are reacted under microwave conditions of 80W for 15 minutes. After the reaction is completed, the mixture is gradually restored to room temperature, a small amount of water is added to quench the reaction, and the mixture is extracted with ethyl acetate and saturated brine. The organic phase is concentrated and purified by column chromatography with a volume ratio of n-hexane:ethyl acetate = 20:1 to obtain a yellow oily product of 2-fluoro-acetophenone with a yield of 85-93%.

[0052] Specific Embodiment Four: The preparation method of 2-fluoro-2-arylacetophenone III prepared in this embodiment is as follows: At 105°C, in a PEG200, 18-crown ether-6 system, 2-bromo-2-phenylacetophenone and cesium fluoride are reacted under microwave conditions of 80W for 15 minutes. After the reaction is completed, the mixture is gradually restored to room temperature, a small amount of water is added to quench the reaction, and the mixture is extracted with ethyl acetate and saturated brine. The organic phase is concentrated and purified by column chromatography with a volume ratio of n-hexane:ethyl acetate = 20:1 to obtain a yellow oily product of 2-fluoro-2-phenylacetophenone with a yield of 68-78%.

[0053] Specific Embodiment Five: The preparation method of N-aryl-2-fluoropropionamide IV prepared in this embodiment is as follows: At 105°C, in a PEG200, 18-crown ether-6 system, 2-bromo-2-phenylacetophenone and cesium fluoride are reacted under microwave conditions of 80W for 15 minutes. After the reaction is completed, the temperature is gradually reduced to room temperature, a small amount of water is added to quench the reaction, ethyl acetate and saturated brine are used for extraction, the organic phase is concentrated, and column chromatography is performed with a volume ratio of n-hexane:ethyl acetate = 7:1 to obtain 2-fluoro-N-(4-phenyl)propionamide white solid with a yield of 75-83%.

[0054] Specific Implementation Method Six: The preparation method of N-aryl-2-fluorophenylacetamide V prepared in this implementation method is as follows: At 105°C, in a PEG200, 18-crown ether-6 system, 2-bromo-N-methyl-N,2-diphenylacetamide and cesium fluoride are reacted under microwave conditions of 80W for 15 minutes. After the reaction is completed, the temperature is gradually reduced to room temperature, a small amount of water is added to quench the reaction, ethyl acetate and saturated brine are used for extraction, the organic phase is concentrated, and column chromatography is performed with a volume ratio of n-hexane:ethyl acetate = 7:1 to obtain a yellow oily substance of 2-fluoro-N-methyl-N,2-diphenylacetamide with a yield of 70-78%.

[0055] The embodiments of the present invention will be described in detail below. The following embodiments are implemented based on the technical solution of the present invention, and detailed implementation schemes and specific operation processes are given. However, the protection scope of the present invention is not limited to the following embodiments.

[0056] Example 1:

[0057] This embodiment describes a method for preparing 2-fluoroacetophenone, which is carried out according to the following steps:

[0058] At room temperature, 0.5 mmol of 2-bromoacetophenone, 1.5 mmol of 18-crown ether-6, 1.5 mmol of cesium fluoride, and an appropriate amount of PEG200 as solvent were added to a 10 mL thick-walled glass tube and placed in a microwave reactor. The microwave power was adjusted to 80 W, the reaction temperature to 105°C, and the reaction was carried out at atmospheric pressure for 15 min. After the reaction was completed and cooled, the reaction was monitored using thin-layer chromatography (n-hexane:ethyl acetate = 20:1). The reaction was quenched with a small amount of water. The ethyl acetate was extracted with saturated brine, and the organic phase was concentrated. The solution was then wet-coated with 300-400 mesh silica gel powder. The mobile phase ratio was n-hexane:ethyl acetate = 20:1, yielding a yellow oily liquid with a yield of 88%. The structural data of 2-fluoroacetophenone are: 1 H NMR (300MHz, CDCl3) δ7.95-7.87(m,2H),7.65(t,J=7.4Hz,1H),7.52(t,J=7.6Hz,2H),5.55(d,J=46.9Hz,2H). 13 C NMR (75MHz, CDCl3) δ193.53,193.33,134.12,128.92,127.84,84.75,82.33.

[0059] Example 2: This example describes the preparation method of 2-fluoro-4-chloroacetophenone. All experimental conditions and processing methods are the same as in Example 1, except that 2-bromoacetophenone is replaced with 2-bromo-4-chloroacetophenone. The final product yield is 90%. The structural data of 2-fluoro-4-chloroacetophenone are: 1H NMR (300MHz, CDCl3) δ7.88 (d, J = 8.4Hz, 2H), 7.50 (d, J = 8.8Hz, 2H), 5.51 (d, J = 46.9Hz, 2H). 13 C NMR (75MHz, CDCl3) δ192.52,192.31,135.33,135.15,134.10,130.28,128.06,125.99,84.77,82.33.

[0060] Example 3: This example describes the preparation method of 2-fluoro-4-bromoacetophenone. All experimental conditions and processing methods are the same as in Example 1, except that 2-bromoacetophenone is replaced with 2-bromo-4-bromoacetophenone. The final product yield is 89%. The structural data of 2-fluoro-4-bromoacetophenone are: 1 H NMR (300MHz, CDCl3) δ7.86-7.76 (m, 2H), 7.67 (d, J = 7.9Hz, 2H), 5.68-5.34 (d, J = 46.9Hz, 2H). 13 C NMR (75MHz, CDCl3) δ196.94,196.67,134.56,134.86,133.59,130.22,128.04,127.35,92.90,92.86.

[0061] Example 4: This example describes the preparation method of 2-fluoro-4-chlorophenylacetone. All experimental conditions and processing methods are the same as in Example 1, except that 2-bromoacetophenone is replaced with 2-bromo-4-chlorophenylacetone. The final product yield is 91%. The structural data of 2-fluoro-4-chlorophenylacetone are: 1 H NMR (300MHz, CDCl3) δ7.97(s,1H),7.87(d,J=7.9Hz,1H),7.58(ddd,J=8.0,2.1,1.1Hz, 1H), 7.44 (t, J=7.9Hz, 1H), 5.65 (dq, J=48.5, 6.8Hz, 1H), 1.67 (dd, J=24.1, 6.8Hz, 3H). 13 C NMR (75MHz, CDCl3)δ

[0062] 195.94,195.67,135.56,135.03,133.66,130.02,129.04,127.08,91.68,89.29,18.27,17.97.

[0063] Example 5: This example describes the preparation method of 2-fluoro-2-phenylacetophenone. All experimental conditions and processing methods are the same as in Example 1, except that 2-bromoacetophenone is replaced with 2-bromo-2-phenylacetophenone. The final product yield is 78%. The structural data of 2-fluoro-2-phenylacetophenone are: 1 H NMR (300MHz, CDCl3) δ7.97 (d, J = 7.7Hz, 2H), 7.53 (dd, J = 10.4, 6.6Hz, 3H), 7.48-7.37 (m, 5H), 6.55 (d, J = 48.6Hz, 1H). 13 C NMR (75MHz, CDCl3) δ194.41,194.12,134.38,134.12,134.01,133.78,129.67,129.63,129.10,129.06,128.70,127.44,127.37,95.17,92.71.

[0064] Example 6: Preparation of 2-fluoro-1-(4-methylphenyl)-2-phenylethane-1-one. All experimental conditions and processing methods were the same as in Example 1, except that 2-bromoacetophenone was replaced with 2-bromo-1-(4-methylphenyl)-2-phenylethane-1-one. The final product yield was 75%. The structural data of 2-fluoro-1-(4-methylphenyl)-2-phenylethane-1-one are: 1 H NMR (300MHz, CDCl3) δ7.85 (s, 2H), 7.50 (d, J = 5.9Hz, 2H), 7.40 (dd, J = 5.1, 1.9Hz, 3H), 7.23 (d, J = 8.0Hz, 2H), 6.52 (d, J = 48.7Hz, 1H), 2.39 (s, 3H). 13 C NMR (75MHz, CDCl3) δ193.93,193.65,144.82,134.57,134.30,131.44,129. 57,129.54,129.39,129.18,129.04,127.42,127.35,95.09,92.64,21.74.

[0065] Example 7: Preparation of 2-fluoro-1-(4-ethylphenyl)-2-phenylethane-1-one. All experimental conditions and processing methods were the same as in Example 1, except that 2-bromoacetophenone was replaced with 2-bromo-1-(4-ethylphenyl)-2-phenylethane-1-one. The final product yield was 78%. The structural data of 2-fluoro-1-(4-ethylphenyl)-2-phenylethane-1-one are: 1H NMR (300MHz, CDCl3) δ7.90 (d, J = 8.3Hz, 2H), 7.57-7.47 (m, 2H), 7.40 (d, J = 7.4Hz, 3H), 7. 26(d,J=8.3Hz,2H), 6.54(d,J=48.7Hz,1H), 2.68(q,J=7.6Hz,2H), 1.24(t,J=7.6Hz,3H). 13 C NMR (75MHz, CDCl3) δ193.93,193.65,150.94,134.59,134.32,131.63,129.60, 129.56,129.29,129.07,128.23,127.47,127.40,95.07,92.63,28.99,15.02.

[0066] Example 8: Preparation of 2-fluoro-1-(4-methoxyphenyl)-2-phenylethane-1-one. All experimental conditions and processing methods were the same as in Example 1, except that 2-bromoacetophenone was replaced with 2-bromo-1-(4-methoxyphenyl)-2-phenylethane-1-one. The final product yield was 72%. The structural data of 2-fluoro-1-(4-methoxyphenyl)-2-phenylethane-1-one are: 1 H NMR (300MHz, CDCl3) δ7.97(d,J=9.0Hz,2H),7.50(d,J=5.8Hz,2H),7.40(d,J=7.1Hz,3H),6.91(d,J=8.7Hz,2H),6.49(d,J=48.8Hz,1H),3.84(s,3H). 13 CNMR (75MHz, CDCl3) δ192.81,192.53,163.96,134.83,134.57,131.50,129.50,129.01,127.22,126.89,95.16,92.70,55.48.

[0067] Example 9: Preparation of 2-fluoro-2-(4-chlorophenyl)acetophenone. All experimental conditions and processing methods were the same as in Example 1, except that 2-bromoacetophenone was replaced with 2-bromo-2-(4-chlorophenyl)acetophenone. The final product yield was 69%. The structural data of 2-fluoro-2-(4-chlorophenyl)acetophenone are: 1 H NMR (300MHz, CDCl3) δ7.91 (dd, J=8.5, 1.8Hz, 2H), 7.55-7.36 (m, 7H), 6.46 (d, J=48.6Hz, 1H). 13C NMR (75MHz, CDCl3) δ193.39,193.09,140.33,134.12,133.85,132.25,132. 23,130.58,130.53,129.76,129.72,129.06,127.19,127.11,95.44,92.97.

[0068] Example 10: Preparation of 2-fluoro-2-(4-fluorophenyl)acetophenone. All experimental conditions and processing methods were the same as in Example 1, except that 2-bromo-acetophenone was replaced with 2-bromo-2-(4-fluorophenyl)acetophenone. The final product yield was 73%. The structural data of 2-fluoro-2-(4-fluorophenyl)acetophenone are: 1 H NMR (300MHz, CDCl3) δ8.01 (dd, J = 8.8, 5.4Hz, 2H), 7.54-7.37 (m, 5H), 7.11 (t, J = 8.6Hz, 2H), 6.47 (d, J = 48.7Hz, 1H). 13 C NMR (75MHz, CDCl3) δ192.99,192.70,167.66,164.26,134.26,134.00,132.03,131.99,1 31.91,131.86,129.70,129.67,129.14,127.16,127.08,116.08,115.79,95.45,92.98.

[0069] Example 11: This example describes the preparation method of 2-fluoro-N-(4-chlorophenyl)propionamide, carried out according to the following steps: At room temperature, 0.4 mmol of 2-bromo-N-(4-chlorophenyl)propionamide, 0.6 mmol of 18-crown ether-6, 1.2 mmol of cesium fluoride, and an appropriate amount of PEG200 as solvent were added to a 10 mL thick-walled glass tube, placed in a microwave reactor, and the microwave power was adjusted to 80 W. The reaction temperature was 105°C, and the reaction was carried out at atmospheric pressure for 15 min. After the reaction was completed and cooled, the reaction was monitored using thin-layer chromatography (n-hexane:ethyl acetate = 7:1). The reaction was quenched with a small amount of water. The ethyl acetate was extracted with saturated brine, and the organic phase was concentrated. The solution was then wet-coated with 300-400 mesh silica gel powder. The mobile phase ratio was n-hexane:ethyl acetate = 7:1, yielding a white solid with a yield of 80%. The structural data of 2-fluoro-N-(4-chlorophenyl)propionamide are: 1 H NMR (300MHz, CDCl3)δ

[0070] 8.03(s,1H),7.55(d,J=8.9Hz,2H),7.33(d,J=8.9Hz,2H),5.13(dq,J=49.4,6.8Hz,1H),1.68(dd,J=24.9,6.8Hz,3H). 13 C NMR (75MHz, CDCl3) δ168.77,168.53,135.26,129.97,129.15,121.20,90.10,87.65,18.52,18.24.

[0071] Example 12: This example describes the preparation method of 2-fluoro-N-(4-methoxyphenyl)propionamide. All experimental conditions and processing methods are the same as in Example 11, except that 2-bromo-N-(4-chlorophenyl)propionamide is replaced with 2-bromo-N-(4-methoxyphenyl)propionamide. The product yield is 78%. The structural data of the product 2-fluoro-N-(4-methoxyphenyl)propionamide are: 1 H NMR (300MHz, CDCl3) δ7.98 (s, 1H), 7.48 (d, J = 9.0Hz, 2H), 6.88 (d, J = 9.0Hz, 2H), 5.11 (dq, J = 49.5, 6.8Hz, 1H), 3.80 (s, 3H), 1.67 (dd, J = 24.9, 6.8Hz, 3H). 13 C NMR (75MHz, CDCl3) δ168.57,168.33,156.78,129.77,121.79,114.19,90.14,87.70,55.46,18.61,18.33.

[0072] Example 13: This example describes the preparation method of 2-fluoro-N-(3,4,5-methoxyphenyl)propionamide. All experimental conditions and processing methods are the same as in Example 11, except that 2-bromo-N-(4-chlorophenyl)propionamide is replaced with 2-fluoro-N-(3,4,5-methoxyphenyl)propionamide. The product yield is 75%. The structural data of the product 2-fluoro-N-(3,4,5-methoxyphenyl)propionamide are as follows: 1 H NMR (300MHz, CDCl3) δ7.95 (s, 1H), 6.89 (s, 2H), 5.12 (dq, J = 49.3, 6.8Hz, 1H), 3.85 (d, J = 11.0Hz, 9H), 1.68 (dd, J = 24.9, 6.8Hz, 3H). 13C NMR (75MHz, CDCl3) δ168.66,168.42,153.39,135.08,132.78,97.56,90.10,87.65,60.97,56.12,18.54,18.26.

[0073] Example 14: This example describes the preparation method of 2-fluoro-N-(4-chloro-phenyl)-2-phenyl-acetamide. All experimental conditions and processing methods are the same as in Example 11, except that 2-bromo-N-(4-chlorophenyl)propionamide is replaced with 2-bromo-N-(4-chloro-phenyl)-2-phenyl-acetamide. The product yield is 69%. The structural data of the product 2-fluoro-N-(4-chloro-phenyl)-2-phenyl-acetamide are: 1 H NMR (300MHz, CDCl3) δ8.23 (s, 1H), 7.60-7.48 (m, 4H), 7.48-7.41 (m, 3H), 7.33 (d, J = 8.9Hz, 2H), 5.91 (d, J = 48.4Hz, 1H). 13 CNMR (75MHz, CDCl3) δ166.64,166.36,135.18,134.33,134.08,130.15,129.70,129.17,128.84,126.57,121.29,93.09,90.59.

[0074] Example 15: This example describes the preparation method of 2-fluoro-N-(4-methoxy-phenyl)-2-phenyl-acetamide. All experimental conditions and processing methods are the same as in Example 11, except that 2-bromo-N-(4-chlorophenyl)propionamide is replaced with 2-bromo-N-(4-methoxy-phenyl)-2-phenyl-acetamide. The product yield is 72%. The structural data of the product 2-fluoro-N-(4-methoxy-phenyl)-2-phenyl-acetamide are: 1 H NMR (300MHz, CDCl3) δ8.14 (s, 1H), 7.60-7.36 (m, 7H), 6.90 (d, J = 12.4Hz, 2H), 5.90 (d, J = 48.6Hz, 1H), 3.82 (s, 3H). 13 CNMR (75MHz, CDCl3) δ183.53,156.92,129.71,129.53,128.75,126.71,121.81,114.25,93.14,90.63,55.48.

[0075] Example 16: This example describes the preparation method of 2-fluoro-N-methyl-N,2-diphenylacetamide. All experimental conditions and processing methods are the same as in Example 11, except that 2-bromo-N-(4-chlorophenyl)propionamide is replaced with 2-bromo-N-methyl-N,2-diphenylacetamide. The product yield is 73%. The structural data of the product 2-fluoro-N-methyl-N,2-diphenylacetamide are: 1 H NMR (300MHz, CDCl3) δ7.43-7.30(m,5H),7.13(d,J=7.1Hz,2H),6.97(s,2H),5.71(d,J=48.2Hz,1H),3.29(s,3H). 13 C NMR (75MHz, CDCl3) δ167.93,167.58,141.78,141.74,134.61,134.34,129. 79,129.56,129.52,128.51,127.93,127.88,127.82,89.45,87.10,37.88.

[0076] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A microwave-assisted method for preparing α-carbonyl fluorides, characterized in that: This method involves mixing an α-carbonyl bromide compound with CsF, 18-crown ether-6, and PEG200, and then reacting the mixture in a microwave reactor at a specific power and temperature to obtain an α-carbonyl fluorine compound in yield of 65–95%. The structural formula I of the α-carbonyl fluorine compound is: Wherein, structural formula I represents the selected structures as follows: II: 2-Fluoroacetaldehyde (ketone): III: 2-Fluoro-2-arylacetone: IV: N-aryl-2-fluoropropionamide: V: N-aryl-2-fluorophenylacetamide: In II, R3 = H, Cl, Br; R4 = H, CH3; in III, R5 = H, CH3O, CH3CH2; R6 = H, Cl, F; in IV, R7 = Cl, CH3O; and in V, R8 = H, Cl, CH3O.

2. The method for preparing microwave-assisted α-carbonyl fluoride according to claim 1, characterized in that: The microwave power range is 60-160W.

3. The method for preparing microwave-assisted α-carbonyl fluoride according to claim 1, characterized in that; The temperature range is 100℃-150℃.

4. The method for preparing microwave-assisted α-carbonyl fluoride according to claim 3, characterized in that: The reaction time is 15-20 minutes.

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