Method for preparing < 18 > O labeled ketone by catalyzing deoxidation of alcohol through pyrane salt

Abstract

The invention discloses a method for preparing 18O-labeled ketone by catalyzing alcohol deoxidation through pyrane salt, and belongs to the technical field of organic synthesis. According to the process disclosed by the invention, the tertiary benzyl alcohol is taken as a raw material, the triphenyl pyran salt is taken as a catalyst, H218O is taken as a 18O source under the irradiation of visible light, and the 18O-labeled ketone can be obtained at a relatively high yield. According to the method, acid and high-temperature conditions are not needed, meanwhile, residues of transition metal are avoided, a novel low-cost organic photocatalyst is adopted, alcohol can be catalyzed to be oxidized into ketone under mild reaction conditions, and meanwhile 18O labeling is carried out.

Description

Technical Field

[0001] The invention belongs to the technical field of organic synthesis, and specifically relates to a method for preparing alcohol by deoxygenation catalyzed by pyrylium salt. 18 O-labeled ketone method. Background Art

[0002] The oxidation of alcohols to carbonyl compounds is an important reaction in organic synthesis. Generally speaking, primary alcohols and secondary alcohols are easily oxidized to ketones in the presence of strong oxidants. With the development of electrocatalytic synthesis chemistry, primary alcohols and secondary alcohols can be synthesized into ketones under electrooxidation. Chem. Eur. J. 2024, 30, e202402986; J. Org. Chem. 2024, 89, 15864).

[0003] However, for tertiary alcohols, it is a major challenge to synthesize ketones under green and mild conditions by cleaving the CC bond. In addition to Knowles's realization of the photocatalytic oxidation of methoxy-substituted aromatic tertiary alcohols to ketones ( J. Am. Chem. Soc. 2016, 138, 10794), current strategies all require transition metals and equivalent oxidants ( Chin. Chem. Lett. 2023, 34, 108454; Chin. Chem. Lett. 2024, 35, 108835). Given the important role of isotope labeling in chemistry, biology, and medicinal chemistry, commercially available H2 18 O, the development of a green and mild synthesis of 18-O isotope labeled ketones has important research value. Summary of the invention

[0004] The object of the present invention is to provide a method for preparing alcohol by deoxygenation catalyzed by pyrylium salt 18 The method for labeling ketone with O is specifically achieved by the following technical solution: Preparation of alcohol deoxygenation catalyzed by pyrylium salt 18 O-labeling of ketones with tertiary benzyl alcohols As raw materials, triaryl pyryl salt As a photocatalyst, oxidation to ketones occurs simultaneously under visible light irradiation. 18 O mark.

[0005] Furthermore, the raw materials The R1, R2, and R3 groups are various substituted aryl, heteroaryl, or alkyl groups.

[0006] Furthermore, the triaryl pyryl salt is a triphenyl pyryl salt .

[0007] Furthermore, the amount of photocatalyst added is 5%-20% by mole of the raw material.

[0008] Furthermore, the reaction was carried out in an air atmosphere using acetonitrile as solvent.

[0009] Furthermore, the visible light is white light, blue light or sunlight.

[0010] Further, 18 O source is H2 18 O.

[0011] The synthetic route of the present invention is as follows:

[0012] Typical reactions are as follows:

[0013] The beneficial effects of the present invention are: The present invention has mild conditions, does not require acid and high temperature conditions, and avoids the residue of transition metals. It uses low-cost organic photocatalysts to directly oxidize stable and easy-to-synthesize alcohols into ketones. 18 O mark. DETAILED DESCRIPTION

[0014] In order to make the purpose, technical scheme and advantages of the present invention clearer, the technical scheme of the present invention will be clearly and completely described below in conjunction with the embodiments. If the specific conditions are not specified in the embodiments, they are carried out according to the conventional conditions or the conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments is not specified, they are all conventional products that can be purchased commercially.

[0015] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0016] The photocatalyst triphenylpyrylium salt used in the present invention is synthesized by the following method:

[0017] The synthesis was carried out according to the literature and repeated experiments. The specific steps are as follows: In a 100 mL distillation flask, add a magnetic stirrer, then add chalcone (21.0 g, 100 mmol) weighed on an analytical balance, add 20 mL of DCE (1,2-dichloroethane) in air, then add acetophenone (6.1 g, 50 mmol) with a syringe, and stir the mixture on a magnetic stirrer until dissolved. After setting up the reflux device, preheat to 110 °C, then draw HBF4 solution (about 20 mL, 100 mmol) with a syringe, carefully add it dropwise to the distillation flask, and then react for 1.5 h. After the reaction is completed, cool to room temperature and spin dry part of the solvent, add about 80 mL of Et2O solution, stir for 20 min, filter, wash with 20 mL of Et2O, and dry to obtain a light yellow solid.

[0018] The raw material benzyl alcohol used in the present invention is synthesized by the following method:

[0019] According to the literature (Cicco L., Rodríguez-Álvarez MJ, Perna FM, García-Álvarez J., Capriati V..Green Chem., 2017, 19, 3069–3077), the specific steps are as follows: (1) Synthesis steps of secondary alcohols: First, prepare a dry round-bottom flask equipped with a magnetic stirrer, add the reaction raw materials ketone (1.0 equivalent) and methanol (0.8 mmol / mL) into the round-bottom flask, stir and cool it at 0 °C for about 15 minutes, then slowly add sodium borohydride (1.01 equivalent) into the solution, stir the mixture for 14 hours, and warm the reaction solution to room temperature. After the reaction is completed, quench the reaction with H2O (2 mL / mmol). Extract the aqueous phase with EA three times, wash the combined organic phase with brine, and finally dry the combined organic phase with anhydrous MgSO4, and concentrate the solution under reduced pressure to obtain the desired product.

[0020] (2) Synthesis steps of tertiary alcohol: First, prepare a dry reaction bottle with a branch tube, plug the upper end with a rubber stopper, connect the branch tube to a nitrogen device, place the reaction bottle in an ice-water bath, keep it at 0 °C, keep the N2 atmosphere in the reaction bottle, then add the raw material ketone (1.0 equivalent) and anhydrous tetrahydrofuran (1.0 mmol / mL) into the reaction container (if the raw material ketone is solid, we can add the ketone to the reaction bottle first and then connect the device); then use a syringe to draw the Grignard reagent (1.5 equivalents) from the rubber stopper and slowly add it dropwise to the reaction liquid, stir the mixture overnight, and at the same time, warm the reaction liquid to room temperature. After the reaction is completed, quench the reaction with an aqueous solution of ammonium chloride, extract the aqueous phase with EA three times, then dry the mixed liquid with anhydrous MgSO4, monitor the position of the product point by thin layer chromatography, and finally purify it by silica gel column chromatography to obtain the desired product.

[0021] Example 1 Weigh the photocatalyst triphenylpyrylium salt (7.9 mg, 0.01 mmol) and add it to the reaction tube. Add 2 mL of ultra-dry acetonitrile in an air atmosphere. Then carefully add (39.6 mg, 0.2 mmol), and then H2 18 O (120.0 mg, 6 mmol), then placed under two 18 W white light lamps and reacted at room temperature for 6 h. Dry loading, column chromatography (300-400 mesh chromatography silica gel) to obtain the product 24.4 mg, yield 78%, 18 O labeling rate was 88%. 1 H NMR (400 MHz, Chloroform- d ) δ 7.90 (d, J = 8.4 Hz, 2H), 7.44 (d, J = 8.5 Hz, 2H),2.60 (s, 3H). Example 2 Weigh the photocatalyst triphenylpyrylium salt (7.9 mg, 0.01 mmol) and add it to the reaction tube. Add 2 mL of ultra-dry acetonitrile in an air atmosphere. Then carefully add (45.6 mg, 0.2 mmol), and then H2 18 O (120.0 mg, 6 mmol), then placed under two 18 W white light lamps and reacted at room temperature for 6 h. Dry loading, column chromatography (300-400 mesh silica gel) to obtain the product 36.6 mg, yield 92%, 18 O labeling rate 90%. 1 H NMR (400 MHz, Chloroform-d ) δ 7.8 (d, J = 8.4 Hz, 2H), 7.6 (d, J = 6.9 Hz, 2H), 2.6 (s, 3H). Example 3 Weigh the photocatalyst triphenylpyrylium salt (7.9 mg, 0.01 mmol) and add it to the reaction tube. Add 2 mL of ultra-dry acetonitrile in an air atmosphere. Then carefully add (39.6 mg, 0.2 mmol), and then H2 18 O (120.0 mg, 6 mmol), then placed under two 18 W white light lamps and reacted at room temperature for 6 h. Dry loading, column chromatography (300-400 mesh silica gel) to obtain the product 31.6 mg, yield 93%, 18 O labeling rate was 93%. 1 H NMR (400 MHz, Chloroform- d ) δ 7.9 (d, J = 8.2 Hz, 2H), 7.4 (d, J = 8.2 Hz, 2H), 3.0 (q, J = 7.3Hz, 2H), 1.2 (t, J = 7.2 Hz, 3H). Example 4 Weigh the photocatalyst triphenylpyrylium salt (7.9 mg, 0.01 mmol) and add it to the reaction tube. Add 2 mL of ultra-dry acetonitrile in an air atmosphere. Then carefully add (36.0 mg, 0.2 mmol), and then H2 18 O (120.0 mg, 6 mmol), then placed under two 18 W white light lamps and reacted at room temperature for 6 h. Dry loading, column chromatography (300-400 mesh chromatography silica gel) to obtain the product 24.9 mg, yield 69%, 18 O labeling rate was 94%. 1 H NMR (400 MHz, Chloroform- d ) δ 8.1 (s, 1H), 7.8 (d, J = 7.9 Hz, 1H), 7.7 (d, J = 8.6Hz, 1H), 7.4 (td, J= 7.8, 3.0 Hz, 1H), 2.6 (s, 3H), 2.2 (s, 1H), 1.6 (s, 6H). Example 5 Weigh the photocatalyst triphenylpyrylium salt (7.9 mg, 0.01 mmol) and add it to the reaction tube. Add 2 mL of ultra-dry acetonitrile in an air atmosphere. Then carefully add (33.8 mg, 0.2 mmol), and then H2 18 O (120.0 mg, 6 mmol), then placed under two 18 W white light lamps and reacted at room temperature for 6 h. Dry loading, column chromatography (300-400 mesh silica gel) to obtain the product 18.5 mg, yield 66%, 18 O labeling rate is 85%. 1 H NMR (400 MHz, Chloroform- d ) δ 3.02 (q, J = 7.2 Hz, 2H), 1.23 (t, J = 7.3 Hz, 3H). Example 6 Weigh the photocatalyst triphenylpyrylium salt (7.9 mg, 0.01 mmol) and add it to the reaction tube. Add 2 mL of ultra-dry acetonitrile in an air atmosphere. Then carefully add (48.0 mg, 0.2 mmol), and then H2 18 O (120.0 mg, 6 mmol), then placed under two 18 W white light lamps and reacted at room temperature for 6 h. Dry loading, column chromatography (300-400 mesh silica gel) to obtain the product 40.1 mg, yield 94%, 18 O labeling rate was 89%. 1 H NMR (400 MHz, Chloroform- d ) δ 7.8 (d, J = 8.5 Hz, 2H), 7.6 (d, J = 8.6 Hz, 2H), 3.0 (q, J = 7.2Hz, 2H), 1.2 (t, J = 7.2 Hz, 3H). Example 7 Weigh the photocatalyst triphenylpyrylium salt (7.9 mg, 0.01 mmol) and add it to the reaction tube. Add 2 mL of ultra-dry acetonitrile in an air atmosphere. Then carefully add (56.4 mg, 0.2 mmol), and then H2 18 O (120.0 mg, 6 mmol), then placed under two 18 W white light lamps and reacted at room temperature for 6 h. Dry loading, column chromatography (300-400 mesh chromatography silica gel) to obtain the product 30.7 mg, yield 72%, 18 O labeling rate is 91%. 1 HNMR (400 MHz, Chloroform- d ) δ 7.9 (d, J = 8.1 Hz, 2H), 7.4 (d, J = 8.2 Hz, 2H),2.9 (t, J = 7.5 Hz, 2H), 1.7 (m, J = 9.0, 8.1 Hz, 2H), 1.4 – 1.3 (m, 4H), 0.9 (t, J = 7.1 Hz, 3H). Example 8 Weigh the photocatalyst triphenylpyrylium salt (7.9 mg, 0.01 mmol) and add it to the reaction tube. Add 2 mL of ultra-dry acetonitrile in an air atmosphere. Then carefully add (48.4 mg, 0.2 mmol), and then H2 18 O (120.0 mg, 6 mmol), then placed under two 18 W white light lamps and reacted at room temperature for 6 h. Dry loading, column chromatography (300-400 mesh silica gel) to obtain the product 40.6 mg, yield 84%, 18 O labeling rate was 89%.

[0022] Example 9 Weigh the photocatalyst triphenylpyrylium salt (7.9 mg, 0.01 mmol) and add it to the reaction tube. Add 2 mL of ultra-dry acetonitrile in an air atmosphere. Then carefully add (54.0 mg, 0.2 mmol), and then H2 18 O (120.0 mg, 6 mmol), then placed under two 18 W white light lamps and reacted at room temperature for 6 h. Dry loading, column chromatography (300-400 mesh chromatography silica gel) to obtain the product 44.7 mg, yield 92%, 18 O labeling rate was 84%.

[0023] Example 10 Weigh the photocatalyst triphenylpyrylium salt (7.9 mg, 0.01 mmol) and add it to the reaction tube. Add 2 mL of ultra-dry acetonitrile in an air atmosphere. Then carefully add (54.8 mg, 0.2 mmol), and then H2 18 O (40.0 mg, 2 mmol), then placed under two 18 W white light lamps and reacted at room temperature for 6 h. Dry loading, column chromatography (300-400 mesh silica gel) to obtain the product 34.9 mg, yield 95%, 18 O labeling rate 60%. 1 H NMR (400 MHz, Chloroform- d ) δ 7.84 – 7.76 (m, 4H), 7.61 – 7.55 (m, 2H), 7.47 (t, J = 7.7 Hz,4H). Embodiment 11 Weigh the photocatalyst triphenylpyrylium salt (7.9 mg, 0.01 mmol) and add it to the reaction tube. Add 2 mL of ultra-dry acetonitrile in an air atmosphere. Then carefully add (38.4 mg, 0.2 mmol), and then H2 18 O (40.0 mg, 2 mmol), then placed under two 18 W white light lamps and reacted at room temperature for 6 h. Dry loading, column chromatography (300-400 mesh silica gel) to obtain the product 19.1 mg, yield 64%, 18 O labeling rate 80%. 1 H NMR (400 MHz, Chloroform- d ) δ 8.01 – 7.86 (m, 2H), 7.55 (t, J = 7.3 Hz, 1H), 7.50 – 7.41 (m,2H), 2.95 (t, J = 7.3 Hz, 2H), 1.78 (h, J = 7.4 Hz, 2H), 1.01 (t, J = 7.4 Hz, 3H). Example 12 Weigh the photocatalyst triphenylpyrylium salt (7.9 mg, 0.01 mmol) and add it to the reaction tube. Add 2 mL of ultra-dry acetonitrile in an air atmosphere. Then carefully add (54.0 mg, 0.2 mmol), and then H218 O (40.0 mg, 2 mmol), then placed under two 18 W white light lamps and reacted at room temperature for 6 h. Dry loading, column chromatography (300-400 mesh silica gel) to obtain the product 20.7 mg, yield 76%, 18 O labeling rate 80%. 1 H NMR (400 MHz, Chloroform- d ) δ 7.97 (d, J = 8.2 Hz, 2H), 7.60 – 7.51 (m, 1H), 7.46 (t, J = 7.8Hz, 2H), 3.01 (q, J = 7.3 Hz, 2H), 1.23 (t, J = 7.2 Hz, 3H). Embodiment 13 Weigh the photocatalyst triphenylpyrylium salt (7.9 mg, 0.01 mmol) and add it to the reaction tube. Add 2 mL of ultra-dry acetonitrile in an air atmosphere. Then carefully add (49.2 mg, 0.2 mmol), and then H2 18 O (40.0 mg, 2 mmol), then placed under two 18 W white light lamps and reacted at room temperature for 6 h. Dry loading, column chromatography (300-400 mesh silica gel) to obtain the product 22.4 mg, yield 68%, 18 O labeling rate was 77%. 1 H NMR (400 MHz, Chloroform- d ) δ 7.96 (d, J = 7.7 Hz, 2H), 7.55 (t, J = 7.5 Hz, 1H), 7.45 (t, J =7.6 Hz, 2H), 2.96 (t, J = 7.5 Hz, 2H), 1.73 (q, J = 7.4 Hz, 2H), 1.41 (q, J = 7.6Hz, 2H), 0.95 (t, J = 7.5 Hz, 3H). Embodiment 14 Weigh the photocatalyst triphenylpyrylium salt (7.9 mg, 0.01 mmol) and add it to the reaction tube. Add 2 mL of ultra-dry acetonitrile in an air atmosphere. Then carefully add (57.6 mg, 0.2 mmol), and then H2 18 O (30.0 mg, 1.5 mmol), then placed under two 18 W white light lamps and reacted at room temperature for 6 h. Dry loading, column chromatography (300-400 mesh chromatography silica gel) to obtain the product 30.0 mg, yield 76%, 18 O labeling rate was 76%. 1 H NMR (400 MHz, Chloroform- d ) δ 8.1 – 7.9 (m, 2H), 7.5 (q, J = 6.2, 5.0 Hz, 1H), 7.5– 7.4 (m, 2H), 7.4 – 7.2 (m, 5H), 4.3 (s, 2H). Embodiment 15 Weigh the photocatalyst triphenylpyrylium salt (7.9 mg, 0.01 mmol) and add it to the reaction tube. Add 2 mL of ultra-dry acetonitrile in an air atmosphere. Then carefully add (50.8 mg, 0.2 mmol), and then H2 18 O (120.0 mg, 6 mmol), then placed under two 18 W white light lamps and reacted at room temperature for 12 h. Dry loading, column chromatography (300-400 mesh silica gel) to obtain the product 42.9 mg, yield 95%, 18 O labeling rate was 79%. 1 H NMR (400 MHz, Chloroform- d ) δ 7.9 (d, J = 8.8 Hz, 2H), 7.6 (d, J = 6.2 Hz, 2H), 2.7 – 2.5 (m,1H), 1.3 – 1.2 (m, 2H), 1.1 – 1.0 (m, 2H). Example 16 Weigh the photocatalyst triphenylpyrylium salt (7.9 mg, 0.01 mmol) and add it to the reaction tube. Add 2 mL of ultra-dry acetonitrile in an air atmosphere. Then carefully add (27.2 mg, 0.2 mmol), and then H2 18O (120.0 mg, 6 mmol), then placed under two 18 W white light lamps and reacted at room temperature for 12 h. Dry loading, column chromatography (300-400 mesh silica gel) to obtain the product 16.6 mg, yield 68%, 18 O labeling rate was 89%.

[0024] Embodiment 17 Weigh the photocatalyst triphenylpyrylium salt (7.9 mg, 0.01 mmol) and add it to the reaction tube. Add 2 mL of ultra-dry acetonitrile in an air atmosphere. Then carefully add (67.6 mg, 0.2 mmol), and then H2 18 O (120.0 mg, 6 mmol), then placed under two 18 W white light lamps and reacted at room temperature for 12 h. Dry loading, column chromatography (300-400 mesh silica gel) to obtain the product 41.5 mg, yield 67%, 18 O labeling rate was 81%. 1 H NMR (400 MHz, Chloroform- d ) δ 7.89 (d, J = 1.8 Hz, 1H), 7.83 (dd, J =7.9, 1.8 Hz, 1H), 7.37 – 7.32 (m, 2H), 7.33 – 7.25 (m, 3H), 3.03 (q, J = 7.2Hz, 2H), 2.32 (s, 3H), 1.25 (t, J = 7.2 Hz, 3H). Embodiment 18 Weigh the photocatalyst triphenylpyrylium salt (7.9 mg, 0.01 mmol) and add it to the reaction tube. Add 2 mL of ultra-dry acetonitrile in an air atmosphere. Then carefully add (39.6 mg, 0.2 mmol), and then H2 18 O (120.0 mg, 6 mmol), then placed under two 18 W white light lamps and reacted at room temperature for 12 h. Dry loading, column chromatography (300-400 mesh silica gel) to obtain the product 23.9 mg, yield 70%, 18 O labeling rate was 79%. 1 H NMR (500 MHz, DMSO- d 6) δ 8.16 (t, J= 2.0 Hz, 1H), 7.85 (tt, J = 7.3, 2.0 Hz, 2H), 7.67 (t, J =7.4 Hz, 1H), 3.41 (q, J = 8.0 Hz, 2H), 1.18 (t, J = 8.0 Hz, 3H). Embodiment 19 Weigh the photocatalyst triphenylpyrylium salt (7.9 mg, 0.01 mmol) and add it to the reaction tube. Add 2 mL of ultra-dry acetonitrile in an air atmosphere. Then carefully add (63.6 mg, 0.2 mmol), and then H2 18 O (120.0 mg, 6 mmol), then placed under two 18 W white light lamps and reacted at room temperature for 12 h. Dry loading, column chromatography (300-400 mesh silica gel) to obtain the product 43.1 mg, yield 95%, 18 O labeling rate was 88%. 1 HNMR (400 MHz, Chloroform- d ) δ 7.98 (d, J = 8.7 Hz, 2H), 7.27 (dp, J = 15.4, 7.5Hz, 5H), 6.91 (d, J = 8.8 Hz, 2H), 4.22 (s, 2H), 3.83 (s, 3H). Embodiment 20 Weigh the photocatalyst triphenylpyrylium salt (7.9 mg, 0.01 mmol) and add it to the reaction tube. Add 2 mL of ultra-dry acetonitrile in an air atmosphere. Then carefully add (50.8 mg, 0.2 mmol), and then H2 18 O (40.0 mg, 2 mmol), then placed under two 18 W white light lamps and reacted at room temperature for 12 h. Dry loading, column chromatography (300-400 mesh silica gel) to obtain the product 33.8 mg, yield 85%, 18 O labeling rate was 78%. 1 H NMR (400MHz, Chloroform- d ) δ 7.9 (d, J = 8.1 Hz, 2H), 7.4 (d, J= 8.2 Hz, 2H), 2.8 (d, J =6.8 Hz, 2H), 2.3 (dp, J = 20.7, 6.8 Hz, 1H), 1.0 (d, J = 5.4 Hz, 6H). Embodiment 21 Weigh the photocatalyst triphenylpyrylium salt (7.9 mg, 0.01 mmol) and add it to the reaction tube. Add 2 mL of ultra-dry acetonitrile in an air atmosphere. Then carefully add (50.6 mg, 0.2 mmol), and then H2 18 O (40.0 mg, 2 mmol), then placed under two 18 W white light lamps and reacted at room temperature for 12 h. Dry loading, column chromatography (300-400 mesh silica gel) to obtain the product 28.2 mg, yield 77%, 18 O labeling rate was 66%. 1 H NMR (400MHz, Chloroform- d ) δ 2.99 – 2.94 (m, 2H), 1.74 (p, J = 7.5 Hz, 2H), 1.37 (h, J =3.7 Hz, 4H), 0.91 (td, J = 6.9, 3.3 Hz, 3H). Embodiment 22 Weigh the photocatalyst triphenylpyrylium salt (7.9 mg, 0.01 mmol) and add it to the reaction tube. Add 2 mL of ultra-dry acetonitrile in an air atmosphere. Then carefully add (52.8 mg, 0.2 mmol), and then H2 18 O (120.0 mg, 6 mmol), then placed under two 18 W white light lamps and reacted at room temperature for 24 h. Dry loading, column chromatography (300-400 mesh chromatography silica gel) to obtain the product 26.8 mg, yield 57%, 18 O labeling rate was 78%. 1 H NMR (400 MHz, Chloroform- d ) δ 7.99 (d, J = 8.4 Hz, 2H), 7.74 (d, J = 8.4 Hz, 2H),3.01 (q, J= 7.2 Hz, 2H), 1.24 (t, J = 7.2 Hz, 3H). Embodiment 23 Weigh the photocatalyst triphenylpyrylium salt (7.9 mg, 0.01 mmol) and add it to the reaction tube. Add 2 mL of ultra-dry acetonitrile in an air atmosphere. Then carefully add (33.6 mg, 0.2 mmol), and then H2 18 O (120.0 mg, 6 mmol), then placed under two 18 W white light lamps and reacted at room temperature for 24 h. Dry loading, column chromatography (300-400 mesh silica gel) to obtain the product 17.0 mg, yield 55%, 18 O labeling rate was 77%. 1 H NMR (400 MHz, Chloroform- d ) δ 7.87 – 7.71 (m, 2H), 7.04 (t, J = 8.9 Hz, 1H), 2.56 (d, J = 1.4Hz, 3H), 2.31 (s, 3H). Embodiment 24 Weigh the photocatalyst triphenylpyrylium salt (7.9 mg, 0.01 mmol) and add it to the reaction tube. Add 2 mL of ultra-dry acetonitrile in an air atmosphere. Then carefully add (52.0 mg, 0.2 mmol), and then H2 18 O (120.0 mg, 6 mmol), then placed under two 18 W white light lamps and reacted at room temperature for 24 h. Dry loading, column chromatography (300-400 mesh chromatography silica gel) to obtain the product 18.8 mg, yield 60%, 18 O labeling rate was 73%. 1 H NMR (400 MHz, Chloroform- d ) δ 7.90 (d, J = 8.4 Hz, 2H), 7.44 (d, J = 8.5 Hz, 2H),2.60 (s, 3H). Embodiment 25 Weigh the photocatalyst triphenylpyrylium salt (15.8 mg, 0.02 mmol) and add it to the reaction tube. Add 2 mL of ultra-dry acetonitrile in an air atmosphere. Then carefully add (42.4 mg, 0.2 mmol), and then H2 18 O (120.0 mg, 6 mmol), then placed under two 18 W white light lamps and reacted at room temperature for 24 h. Dry loading, column chromatography (300-400 mesh chromatography silica gel) to obtain the product The gas phase yield is 70%, 18 O labeling rate was 69%.

[0025] Embodiment 26 Weigh the photocatalyst triphenylpyrylium salt (15.8 mg, 0.02 mmol) and add it to the reaction tube. Add 2 mL of ultra-dry acetonitrile in an air atmosphere. Then carefully add (45.2 mg, 0.2 mmol), and then H2 18 O (120.0 mg, 6 mmol), then placed under two 18 W white light lamps and reacted at room temperature for 24 h. Dry loading, column chromatography (300-400 mesh chromatography silica gel) to obtain the product The gas phase yield is 65%, 18 O labeling rate 65%.

[0026] Embodiment 27 Weigh the photocatalyst triphenylpyrylium salt (15.8 mg, 0.02 mmol) and add it to the reaction tube. Add 2 mL of ultra-dry acetonitrile in an air atmosphere. Then carefully add (53.6 mg, 0.2 mmol), and then H2 18 O (120.0 mg, 6 mmol), then placed under two 18 W white light lamps and reacted at room temperature for 24 h. Dry loading, column chromatography (300-400 mesh chromatography silica gel) to obtain the product 17.7 mg, yield 39%, 18 O labeling rate 70%. 1 HNMR (400 MHz, Chloroform- d ) δ 8.06 – 8.02 (m, 2H), 7.71 – 7.66 (m, 2H), 7.65 – 7.60 (m, 2H), 7.51 – 7.44 (m, 2H), 7.43 – 7.37 (m, 1H), 2.98 (t, J = 7.3 Hz,2H), 1.80 (h, J = 7.4 Hz, 2H), 1.03 (t, J = 7.4 Hz, 3H). Embodiment 28 Weigh the photocatalyst triphenylpyrylium salt (7.9 mg, 0.01 mmol) and add it to the reaction tube. Add 2 mL of ultra-dry acetonitrile in an air atmosphere. Then carefully add (67.3 mg, 0.2 mmol), and then H2 18 O (120.0 mg, 6 mmol), then placed under two 18 W white light lamps and reacted at room temperature for 6 h. Dry loading, column chromatography (300-400 mesh silica gel) to obtain the product 30.0 mg, yield 61%, 18 O labeling rate was 83%. 1 H NMR (400 MHz, Chloroform- d ) δ 7.70 (d, J = 1.8 Hz, 1H), 7.35 (d, J = 1.8 Hz, 1H), 3.18 (t, J =7.2 Hz, 2H), 2.60 (s, 3H), 1.93 (t, J = 7.2 Hz, 2H), 1.36 (s, 9H), 1.26 (s, 6H). Embodiment 29 Weigh the photocatalyst triphenylpyrylium salt (7.9 mg, 0.01 mmol) and add it to the reaction tube. Add 2 mL of ultra-dry acetonitrile in an air atmosphere. Then carefully add (70.1 mg, 0.2 mmol), and then H2 18 O (120.0 mg, 6 mmol), then placed under two 18 W white light lamps and reacted at room temperature for 6 h. Dry loading, column chromatography (300-400 mesh chromatography silica gel) to obtain the product 45.8 mg, yield 88%, 18 O labeling rate was 81%. 1 H NMR (400 MHz, Chloroform- d ) δ 7.66 (s, 1H), 7.20 (s, 1H), 2.57 (s, 3H), 2.50 (s,3H), 1.88 (dqd, J = 13.4, 6.8, 2.6 Hz, 1H), 1.64 (t, J = 13.3 Hz, 1H), 1.40 (dd, J= 13.6, 2.7 Hz, 1H), 1.33 (s, 6H), 1.27 (s, 3H), 1.07 (s, 3H), 1.00 (d, J = 6.8Hz, 3H). Embodiment 30 Weigh the photocatalyst triphenylpyrylium salt (7.9 mg, 0.01 mmol) and add it to the reaction tube. Add 2 mL of ultra-dry acetonitrile in an air atmosphere. Then carefully add (68.4 mg, 0.2 mmol), and then H2 18 O (120.0 mg, 6 mmol), then placed under two 18 W white light lamps and reacted at room temperature for 6 h. Dry loading, column chromatography (300-400 mesh chromatography silica gel) to obtain the product 41.1 mg, yield 82%, 18 O labeling rate was 34%. 1 HNMR (400 MHz, Chloroform- d ) δ 7.75 – 7.71 (m, 4H), 7.49 – 7.45 (m, 4H). Embodiment 31 Weigh the photocatalyst triphenylpyrylium salt (15.8 mg, 0.02 mmol) and add it to the reaction tube. Add 2 mL of ultra-dry acetonitrile in an air atmosphere. Then carefully add (39.6 mg, 0.2 mmol), and then H2 18 O (120.0 mg, 6 mmol), then placed under 456 nm blue light, reacted at room temperature for 12 h. Dry loading, column chromatography (300-400 mesh silica gel) to obtain the product , gas phase yield 45%, 18 O labeling rate was 66%.

[0027] Embodiment 32 Weigh the photocatalyst triphenylpyrylium salt (7.9 mg, 0.01 mmol) and add it to the reaction tube. Add 2 mL of ultra-dry acetonitrile in an air atmosphere. Then carefully add (48.0 mg, 0.2 mmol), and then H2 18 O (120.0 mg, 6 mmol), then placed under two 18 W white light lamps and reacted at room temperature for 24 h. Dry loading, column chromatography (300-400 mesh chromatography silica gel) to obtain the product , gas phase yield 27%, 18 O labeling rate was 69%.

[0028] Embodiment 33 Weigh the photocatalyst triphenylpyrylium salt (7.9 mg, 0.01 mmol) and add it to the reaction tube. Add 2 mL of ultra-dry acetonitrile in an air atmosphere. Then carefully add (39.6 mg, 0.2 mmol), and then H2 18 O (120.0 mg, 6 mmol), then placed under sunlight and reacted at room temperature for 6 h. Dry loading, column chromatography (300-400 mesh chromatography silica gel) to obtain the product 21.9 mg, yield 70%, 18 O labeling rate was 93%. 1 H NMR (400 MHz, Chloroform- d ) δ 7.90 (d, J = 8.4 Hz, 2H), 7.44 (d, J = 8.5 Hz, 2H), 2.60 (s, 3H). Embodiment 34 Weigh the photocatalyst triphenylpyrylium salt (23.8 mg, 0.03 mmol) and add it to the reaction tube. Add 6 mL of ultra-dry acetonitrile in an air atmosphere. Then carefully add (59.4 mg, 0.3 mmol), and then H2 18 O (180.0 mg, 6 mmol), the reaction solution was passed through a continuous flow reactor, and 4 mL (0.2 mmol) was collected after 2 hours under the irradiation of two 23 W white lamps. The product was obtained by dry loading and column chromatography (300-400 mesh silica gel) 26.6 mg, yield 78%, 18 O labeling rate was 61%. 1 H NMR (500 MHz, DMSO- d 6) δ 8.16 (t, J = 2.0 Hz, 1H),7.85 (tt, J = 7.3, 2.0 Hz, 2H), 7.67 (t, J = 7.4 Hz, 1H), 3.41 (q, J = 8.0 Hz, 2H),1.18 (t, J = 8.0 Hz, 3H). The embodiments described above only express several preferred embodiments of the present invention, and the descriptions thereof are relatively specific and detailed, but are not intended to limit the present invention. It should be noted that for those skilled in the art, the present invention may also have various changes and modifications, and any modifications, equivalent substitutions, improvements, etc. made within the concept and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. Preparation of alcohol deoxygenation catalyzed by pyrylium salt 18 A method for labeling a ketone with O, characterized in that Tertiary benzyl alcohol As raw materials, triaryl pyryl salt As a photocatalyst, oxidation to ketones occurs simultaneously under visible light irradiation. 18 O mark.

2. Preparation of alcohol deoxygenation catalyzed by a pyrylium salt according to claim 1 18 A method for labeling a ketone with O, characterized in that raw material The R1, R2, and R3 groups are various substituted aryl, heteroaryl, or alkyl groups.

3. Preparation of alcohol deoxygenation catalyzed by a pyrylium salt according to claim 1 18 A method for labeling a ketone with O, characterized in that The triaryl pyryl salt is a triphenyl pyryl salt .

4. Preparation of alcohol deoxygenation catalyzed by a pyrylium salt according to claim 1 18 A method for labeling a ketone with O, characterized in that The amount of photocatalyst added is 5%-20% by mole of the raw material.

5. Preparation of alcohol deoxygenation catalyzed by a pyrylium salt according to claim 1 18 A method for labeling a ketone with O, characterized in that The reaction was carried out in air atmosphere using acetonitrile as solvent.

6. Preparation of alcohol deoxygenation catalyzed by a pyrylium salt according to claim 1 18 A method for labeling a ketone with O, characterized in that The visible light is white light, blue light or sunlight.

7. Preparation of alcohol deoxygenation catalyzed by a pyrylium salt according to claim 1 18 A method for labeling a ketone with O, characterized in that 18 O source is H2 18 O.

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