Efficient preparation method of allyl ether compound

Abstract

The invention relates to a synthesis method of an allyl ether compound. According to the method, 2-methylquinoline or acetophenone derivatives are used as raw materials, a selective fluorine reagent Selectfluor is used as an accelerant, dimethyl sulfoxide and ethyl acetate or propyl acetate are used as a mixed solvent, and the allyl ether or propyl ether series derivatives are synthesized with high yield. The preparation method has the advantages of being low in cost, easy to operate, green, free of pollution and the like, and has potential industrial application prospects. The method provides a green, cheap and convenient way for preparing the allyl ether derivative by using 2-methylquinoline or acetophenone compounds as initiators.

Description

[Technical Field]

[0001] This invention relates to an efficient method for preparing allyl ether compounds, belonging to the field of organic synthesis technology. This synthetic method, for the first time, utilizes Selectfluor as a promoter and dimethyl sulfoxide as a solvent and reaction reagent to convert 2-methylquinoline or acetophenone derivatives with ethyl acetate or propyl acetate as raw materials into allyl ether compounds. It features simple operation, inexpensive raw materials, and is environmentally friendly. [Background Technology]

[0002] Ether structural fragments are frequently found in natural products, drug molecules, and functional materials; nitrogen-containing heterocycles such as quinolines, or oxygen-containing aromatic ketones, are important molecular skeletons that play a vital role in the fields of pharmaceuticals and materials. To date, reports on nitrogen-containing heterocycles or aromatic acetophenones have focused on the synthesis and modification of their alkenyl ester derivatives ([1] Zhurnnal Obshchei Khimii, 1964, 34(11), 3783-5. [2] Green Chem., 2022, 24, 5614-5619); however, there are few reports in the literature on the synthesis of novel chemical molecules of nitrogen-containing heterocycles such as quinolines and alkenyl ether derivatives of acetophenone. Among the currently known published literature, the method for synthesizing phenylacetyl alkenyl methyl ether derivatives from acetophenone with methanol and formaldehyde (International Journal of Electrochemical Science, 2024, 19, 100508.) involves two steps, requires a single reaction substrate, and is cumbersome to operate. Furthermore, there are no literature or patent reports on the synthesis of quinoline alkenyl ether derivatives. Therefore, in the field of organic synthesis technology, establishing a concise synthetic method for alkenyl ether derivatives of quinoline or acetophenone is not only completely innovative in terms of synthetic strategy, but also enriches the chemical entity types of organic molecules, which is of great significance.

[0003] We have developed a method for synthesizing allyl ether derivatives of nitrogen-containing heterocyclic compounds such as quinoline and acetophenone, using conventional solvents such as ethyl acetate or propyl acetate as the source of the ether functional groups in the target product and dimethyl sulfoxide as the source of the alkenyl group in the reaction product. With the participation of the selective fluorine reagent Selectfluor, we have achieved the first synthesis of allyl ether derivatives of nitrogen-containing heterocyclic compounds such as quinoline and acetophenone. Specifically, using substituted 2-methylquinoline or acetophenone as starting materials, a mixture of ethyl acetate (or propyl acetate) and dimethyl sulfoxide as the reaction solvent, and Selectfluor as the added promoter, we synthesized their target allyl ether derivatives in a one-pot process. This procedure does not use transition metals and features simple operation, one-pot feeding, environmental friendliness, and a broad range of reaction substrates. Furthermore, the chemical entities of nitrogen-containing heterocyclic allyl ether derivatives such as quinoline are synthesized for the first time. Currently, there are no published documents or patent applications reporting the preparation of allyl ether derivatives using 2-methyl nitrogen-containing heterocyclic compounds or acetophenone, dimethyl sulfoxide, and acetate as starting materials, and Selectfluor as the promoter. [Summary of the Invention]

[0004] This invention develops an efficient method for synthesizing nitrogen-containing heterocyclic derivatives such as quinoline or phenylacetyl alkenyl ethers using selective fluorine reagents. In this preparation method, nitrogen-containing heterocyclic derivatives such as 2-methylquinoline or acetophenone derivatives are used as raw materials, a mixed solvent of dimethyl sulfoxide and ethyl acetate or propyl acetate is used as the reaction solvent, and Selectfluor is added as a promoter. Under simple heating conditions, allyl ether derivatives are synthesized efficiently in a one-pot process.

[0005] The synthesis method of the present invention can be represented by the following reaction formula:

[0006]

[0007] Wherein R is a substituent group: hydrogen, methyl, ethyl, propyl, isopropyl, methoxy, ethoxy, propoxy, phenoxy, fluorine, chlorine, bromine, nitro, trifluoromethyl, cyano, and other functional groups.

[0008] The reactant acetate is ethyl acetate or propyl acetate.

[0009] The 2-methylquinoline of raw material I can be replaced with other nitrogen heterocycles with similar activity: 2-methylquinoxaline, 2-methyl-benzothiazole, 1-methylisoquinoline.

[0010] The invention comprises the following technical operation process: Add raw material I or II to a reaction tube, followed by the promoter Selectfluor, and equal volumes of ethyl acetate and dimethyl sulfoxide. Place the reaction tube containing this mixture in an oil bath, stir magnetically, and after the reaction is complete as monitored by TLC, cool the reaction solution to room temperature, add an appropriate amount of water, and extract three times with ethyl acetate. Collect the organic phase, add an appropriate amount of anhydrous Na2SO4 to the combined organic layer for drying, filter, concentrate the solvent under reduced pressure, and use a mixture of petroleum ether and ethyl acetate as the mobile phase. Separate the crude product using a silica gel column to obtain the target compound: allyl ethyl ether or a propyl ether derivative.

[0011] In the above technical operation process, the reaction temperature for synthesizing alkenyl ether compounds is 120℃ and the reaction time is 10h.

[0012] In the above-mentioned technical operation process, in the synthesis of alkenyl ether compounds, the equivalent molar ratio of reactant I or II to Selectfluor reagent is 1:2; 0.1 mmol of reactant I or II is mixed with 1 mL of dimethyl sulfoxide and 1 mL of ethyl acetate or propyl acetate; in the reaction of the scaled-up materials, the feed ratio remains unchanged.

[0013] Compared with existing technologies, the synthetic method of this invention has significant advantages: the synthetic operation is simple and efficient; the raw materials are low-cost, inexpensive, and readily available; the substrates are widely applicable; the reaction is highly versatile; the reaction has a wide range of applications; and the reaction conditions are mild, requiring no harsh experimental environment, which aligns with the concept of economical and green chemical synthesis and has promising application prospects. This synthetic strategy provides a viable option for preparing complex allyl ether derivatives.

Detailed Implementation Methods

[0014] The following detailed explanation of the present invention with reference to specific embodiments is not intended to limit the scope of the invention.

[0015] Example 1

[0016] In a 15 mL reaction tube, 0.1 mmol of 7-chloro-2-methylquinoline, 0.2 mmol of Selectfluor (a promoter), and 1.0 mL of ethyl acetate were added, followed by the slow addition of 1.0 mL of dimethyl sulfoxide. The reaction tube was placed in an oil bath at 120 °C and magnetically stirred for 10 h. After the reaction was complete as monitored by TLC, the reaction solution was cooled to room temperature, a suitable amount of water was added, and the mixture was extracted three times with ethyl acetate. The organic phases were collected, and the combined organic layers were dried over anhydrous Na₂SO₄. The mixture was filtered, and the solvent was concentrated under reduced pressure. Using a mixture of petroleum ether and ethyl acetate as the mobile phase, the crude product was separated by silica gel column chromatography to obtain the target compound 7-chloro-2-(1-ethoxymethylvinyl)quinoline. The product was a yellow liquid with a yield of 68%. Characterization data: 1 H NMR (400MHz, CDCl3) δ8.10 (d, J=8.7Hz, 1H), 8.06 (dd, J=8.5, 1.8Hz, 1H), 7.78 (d, J=8.1Hz, 1H), 7.72-7.51 (m, 2H) , 7.49 (td, J=7.3, 1.1Hz, 1H), 6.09 (s, 1H), 5.76 (s, 1H), 4.71 (s, 2H), 3.67 (q, J=7.0Hz, 2H), 1.27 (t, J=6.9Hz, 3H). 13 C NMR (100MHz, CDCl3) δ156.63, 147.64, 145.08, 136.10, 129.65, 129.43, 127.40 , 127.36, 126.29, 118.65, 116.95, 70.81, 66.13, 15.33.HRMS(ESI): m / z: calcd for[M+H] + C 14 H 16 NO: 214.1154, found: 214.1161.

[0017] Example 2

[0018] In a 15 mL reaction tube, 0.1 mmol of 6-fluoro-2-methylquinoline, 0.2 mmol of Selectfluor (a promoter), and 1.0 mL of ethyl acetate were added, followed by the slow addition of 1.0 mL of dimethyl sulfoxide. The reaction tube containing this mixture was placed in an oil bath at 120 °C and magnetically stirred for 10 h. After the reaction was complete as monitored by TLC, the reaction solution was cooled to room temperature, an appropriate amount of water was added, and the mixture was extracted three times with ethyl acetate. The organic phases were collected, and the combined organic layers were dried over anhydrous Na₂SO₄. The mixture was filtered, and the solvent was concentrated under reduced pressure. Using a mixture of petroleum ether and ethyl acetate as the mobile phase, the crude product was separated by silica gel column chromatography to obtain the target compound 6-fluoro-2-(1-ethoxymethylvinyl)quinoline. The product was a yellow liquid with a yield of 62%.

[0019] Example 3

[0020] In a 15 mL reaction tube, 0.1 mmol of 6-bromo-2-methylquinoline, 0.2 mmol of Selectfluor (a promoter), and 1.0 mL of ethyl acetate were added, followed by the slow addition of 1.0 mL of dimethyl sulfoxide. The reaction tube was placed in an oil bath at 120 °C and magnetically stirred for 10 h. After the reaction was complete as monitored by TLC, the reaction solution was cooled to room temperature, a suitable amount of water was added, and the mixture was extracted three times with ethyl acetate. The organic phases were collected, and the combined organic layers were dried with an appropriate amount of anhydrous Na₂SO₄. The mixture was filtered, and the solvent was concentrated under reduced pressure. Using a mixture of petroleum ether and ethyl acetate as the mobile phase, the crude product was separated by silica gel column chromatography to obtain the target compound 6-bromo-2-(1-ethoxymethylvinyl)quinoline. The product was a yellow liquid with a yield of 70%.

[0021] Example 4

[0022] In a 15 mL reaction tube, 0.1 mmol of 2,6-dimethylquinoline, 0.2 mmol of Selectfluor (a promoter), and 1.0 mL of ethyl acetate were added, followed by the slow addition of 1.0 mL of dimethyl sulfoxide. The reaction tube containing this mixture was placed in an oil bath at 120 °C and magnetically stirred for 10 h. After the reaction was complete as monitored by TLC, the reaction solution was cooled to room temperature, an appropriate amount of water was added, and the mixture was extracted three times with ethyl acetate. The organic phases were collected, and the combined organic layers were dried over anhydrous Na₂SO₄. The mixture was filtered, and the solvent was concentrated under reduced pressure. Using a mixture of petroleum ether and ethyl acetate as the mobile phase, the crude product was separated by silica gel column chromatography to obtain the target compound 6-methyl-2-(1-ethoxymethylvinyl)quinoline. The product was a yellow liquid with a yield of 65%.

[0023] Example 5

[0024] In a 15 mL reaction tube, 0.1 mmol of 2-methylquinoxaline, 0.2 mmol of Selectfluor (a promoter), and 1.0 mL of ethyl acetate were added, followed by the slow addition of 1.0 mL of dimethyl sulfoxide. The reaction tube containing this mixture was placed in an oil bath at 120 °C and magnetically stirred for 10 h. After the reaction was complete as monitored by TLC, the reaction solution was cooled to room temperature, an appropriate amount of water was added, and the mixture was extracted three times with ethyl acetate. The organic phases were collected, and the combined organic layers were dried over anhydrous Na₂SO₄. The mixture was filtered, and the solvent was concentrated under reduced pressure. Using a mixture of petroleum ether and ethyl acetate as the mobile phase, the crude product was separated by silica gel column chromatography to obtain the target compound 2-(1-ethoxymethylvinyl)quinoxaline. The product was a yellow liquid with a yield of 70%.

[0025] Example 6

[0026] In a 15 mL reaction tube, 0.1 mmol of 1-methylisoquinoline, 0.2 mmol of Selectfluor (a promoter), and 1.0 mL of ethyl acetate were added, followed by the slow addition of 1.0 mL of dimethyl sulfoxide. The reaction tube containing this mixture was placed in an oil bath at 120 °C and magnetically stirred for 10 h. After the reaction was complete as monitored by TLC, the reaction solution was cooled to room temperature, an appropriate amount of water was added, and the mixture was extracted three times with ethyl acetate. The organic phases were collected, and the combined organic layers were dried over anhydrous Na₂SO₄. The mixture was filtered, and the solvent was concentrated under reduced pressure. Using a mixture of petroleum ether and ethyl acetate as the mobile phase, the crude product was separated by silica gel column chromatography to obtain the target compound 1-ethoxymethylvinyl-isoquinoline. The product was a yellow liquid with a yield of 55%.

[0027] Example 7

[0028] In a 15 mL reaction tube, 0.1 mmol of 6-ethoxy-2-methylquinoline, 0.2 mmol of Selectfluor (a promoter), and 1.0 mL of ethyl acetate were added, followed by the slow addition of 1.0 mL of dimethyl sulfoxide. The reaction tube containing this mixture was placed in an oil bath at 120 °C and magnetically stirred for 10 h. After the reaction was complete as monitored by TLC, the reaction solution was cooled to room temperature, a suitable amount of water was added, and the mixture was extracted three times with ethyl acetate. The organic phases were collected, and the combined organic layers were dried over anhydrous Na₂SO₄. The mixture was filtered, and the solvent was concentrated under reduced pressure. Using a mixture of petroleum ether and ethyl acetate as the mobile phase, the crude product was separated by silica gel column chromatography to obtain the target compound 6-ethoxy-2-(1-ethoxymethylvinyl)quinoline. The product was a yellow liquid with a yield of 74%.

[0029] Example 8

[0030] In a 15 mL reaction tube, 0.1 mmol of 2-methylquinoline, 0.2 mmol of Selectfluor (a promoter), and 1.0 mL of ethyl acetate were added, followed by the slow addition of 1.0 mL of dimethyl sulfoxide. The reaction tube containing this mixture was placed in an oil bath at 120 °C and magnetically stirred for 10 h. After the reaction was complete as monitored by TLC, the reaction solution was cooled to room temperature, an appropriate amount of water was added, and the mixture was extracted three times with ethyl acetate. The organic phases were collected, and the combined organic layers were dried over anhydrous Na₂SO₄. The mixture was filtered, and the solvent was concentrated under reduced pressure. Using a mixture of petroleum ether and ethyl acetate as the mobile phase, the crude product was separated by silica gel column chromatography to obtain the target compound 2-(1-ethoxymethylvinyl)quinoline. The product was a yellow liquid with a yield of 80%.

[0031] Example 9

[0032] In a 15 mL reaction tube, 0.1 mmol of 2-methylbenzothiazole, 0.2 mmol of Selectfluor (a promoter), and 1.0 mL of ethyl acetate were added, followed by the slow addition of 1.0 mL of dimethyl sulfoxide. The reaction tube containing this mixture was placed in an oil bath at 120 °C and magnetically stirred for 10 h. After the reaction was complete as monitored by TLC, the reaction solution was cooled to room temperature, an appropriate amount of water was added, and the mixture was extracted three times with ethyl acetate. The organic phases were collected, and the combined organic layers were dried over anhydrous Na₂SO₄. The mixture was filtered, and the solvent was concentrated under reduced pressure. Using a mixture of petroleum ether and ethyl acetate as the mobile phase, the crude product was separated by silica gel column chromatography to obtain the target compound 2-(1-ethoxymethylvinyl)benzothiazole. The product was a yellow liquid with a yield of 75%.

[0033] Example 10

[0034] In a 15 mL reaction tube, 0.1 mmol of 2-methylquinoline, 0.2 mmol of Selectfluor (a promoter), and 1.0 mL of propyl acetate were added, followed by the slow addition of 1.0 mL of dimethyl sulfoxide. The reaction tube containing this mixture was placed in an oil bath at 120 °C and magnetically stirred for 10 h. After the reaction was complete as monitored by TLC, the reaction solution was cooled to room temperature, an appropriate amount of water was added, and the mixture was extracted three times with ethyl acetate. The organic phases were collected, and an appropriate amount of anhydrous Na₂SO₄ was added to the combined organic layers for drying. The mixture was filtered, and the solvent was concentrated under reduced pressure. Using a mixture of petroleum ether and ethyl acetate as the mobile phase, the crude product was separated by silica gel column chromatography to obtain the target compound 2-(1-propoxymethylvinyl)quinoline. The product was a yellow liquid with a yield of 68%.

[0035] Example 11

[0036] In a 15 mL reaction tube, acetophenone (0.1 mmol), Selectfluor (0.2 mmol) as a promoter, and 1.0 mL of ethyl acetate were added, followed by the slow addition of 1.0 mL of dimethyl sulfoxide. The reaction tube containing this mixture was placed in an oil bath at 120 °C and magnetically stirred for 10 h. After the reaction was complete as monitored by TLC, the reaction solution was cooled to room temperature, an appropriate amount of water was added, and the mixture was extracted three times with ethyl acetate. The organic phases were collected, and the combined organic layers were dried over anhydrous Na₂SO₄. The mixture was filtered, and the solvent was concentrated under reduced pressure. Using a mixture of petroleum ether and ethyl acetate as the mobile phase, the crude product was separated by silica gel column chromatography to obtain the target compound 2-ethoxymethyl-1-phenylpropenone. The product was a yellow liquid with a yield of 75%.

[0037] Example 12

[0038] In a 15 mL reaction tube, 0.1 mmol of 4-methylacetophenone, 0.2 mmol of Selectfluor (a promoter), and 1.0 mL of ethyl acetate were added, followed by the slow addition of 1.0 mL of dimethyl sulfoxide. The reaction tube containing this mixture was placed in an oil bath at 120 °C and magnetically stirred for 10 h. After the reaction was complete as monitored by TLC, the reaction solution was cooled to room temperature, an appropriate amount of water was added, and the mixture was extracted three times with ethyl acetate. The organic phases were collected, and the combined organic layers were dried over anhydrous Na₂SO₄. The mixture was filtered, and the solvent was concentrated under reduced pressure. Using a mixture of petroleum ether and ethyl acetate as the mobile phase, the crude product was separated by silica gel column chromatography to obtain the target compound 2-ethoxymethyl-1-p-methylphenylpropenone. The product was a yellow liquid with a yield of 62%.

[0039] Example 13

[0040] In a 15 mL reaction tube, 0.1 mmol of 4-methoxyacetophenone, 0.2 mmol of Selectfluor (a promoter), and 1.0 mL of ethyl acetate were added, followed by the slow addition of 1.0 mL of dimethyl sulfoxide. The reaction tube containing this mixture was placed in an oil bath at 120 °C and magnetically stirred for 10 h. After the reaction was complete as monitored by TLC, the reaction solution was cooled to room temperature, an appropriate amount of water was added, and the mixture was extracted three times with ethyl acetate. The organic phases were collected, and the combined organic layers were dried over anhydrous Na₂SO₄. The mixture was filtered, and the solvent was concentrated under reduced pressure. Using a mixture of petroleum ether and ethyl acetate as the mobile phase, the crude product was separated by silica gel column chromatography to obtain the target compound 2-ethoxymethyl-1-p-methoxyphenylpropenone. The product was a yellow liquid with a yield of 65%.

[0041] Example 14

[0042] In a 15 mL reaction tube, 0.1 mmol of 2-methylacetophenone, 0.2 mmol of Selectfluor (a promoter), and 1.0 mL of ethyl acetate were added, followed by the slow addition of 1.0 mL of dimethyl sulfoxide. The reaction tube containing this mixture was placed in an oil bath at 120 °C and magnetically stirred for 10 h. After the reaction was complete as monitored by TLC, the reaction solution was cooled to room temperature, an appropriate amount of water was added, and the mixture was extracted three times with ethyl acetate. The organic phases were collected, and the combined organic layers were dried over anhydrous Na₂SO₄. The mixture was filtered, and the solvent was concentrated under reduced pressure. Using a mixture of petroleum ether and ethyl acetate as the mobile phase, the crude product was separated by silica gel column chromatography to obtain the target compound 2-ethoxymethyl-1-o-methylphenylpropenone. The product was a yellow liquid with a yield of 61%.

[0043] Example 15

[0044] In a 15 mL reaction tube, 0.1 mmol of 2,4-dichloroacetophenone, 0.2 mmol of Selectfluor (a promoter), and 1.0 mL of ethyl acetate were added, followed by the slow addition of 1.0 mL of dimethyl sulfoxide. The reaction tube containing this mixture was placed in an oil bath at 120 °C and magnetically stirred for 10 h. After the reaction was complete as monitored by TLC, the reaction solution was cooled to room temperature, an appropriate amount of water was added, and the mixture was extracted three times with ethyl acetate. The organic phases were collected, and an appropriate amount of anhydrous Na₂SO₄ was added to the combined organic layers for drying. The mixture was filtered, and the solvent was concentrated under reduced pressure. Using a mixture of petroleum ether and ethyl acetate as the mobile phase, the crude product was separated by silica gel column chromatography to obtain the target compound 1-(2,4-dichlorophenyl)-2-ethoxymethylpropenone. The product was a yellow liquid with a yield of 73%.

[0045] Example 16

[0046] In a 15 mL reaction tube, 0.1 mmol of 4-nitroacetophenone, 0.2 mmol of Selectfluor (a promoter), and 1.0 mL of ethyl acetate were added, followed by the slow addition of 1.0 mL of dimethyl sulfoxide. The reaction tube containing this mixture was placed in an oil bath at 120 °C and magnetically stirred for 10 h. After the reaction was complete as monitored by TLC, the reaction solution was cooled to room temperature, an appropriate amount of water was added, and the mixture was extracted three times with ethyl acetate. The organic phases were collected, and the combined organic layers were dried over anhydrous Na₂SO₄. The mixture was filtered, and the solvent was concentrated under reduced pressure. Using a mixture of petroleum ether and ethyl acetate as the mobile phase, the crude product was separated by silica gel column chromatography to obtain the target compound 2-ethoxymethyl-1-p-nitrophenylpropenone. The product was a yellow liquid with a yield of 71%.

[0047] Example 17

[0048] In a 100 mL reaction tube, 1 mmol of 2-methylquinoline, 2 mmol of Selectfluor (a promoter), and 10 mL of ethyl acetate were added, followed by the slow addition of 10 mL of dimethyl sulfoxide. The reaction tube containing this mixture was placed in an oil bath at 120 °C and magnetically stirred for 10 h. After the reaction was complete as monitored by TLC, the reaction solution was cooled to room temperature, a suitable amount of water was added, and the mixture was extracted three times with ethyl acetate. The organic phases were collected, and an appropriate amount of anhydrous Na₂SO₄ was added to the combined organic layers for drying. The mixture was filtered, and the solvent was concentrated under reduced pressure. Using a mixture of petroleum ether and ethyl acetate as the mobile phase, the crude product was separated by silica gel column chromatography to obtain the target compound 2-(1-ethoxymethylvinyl)quinoline. The product was a yellow liquid with a yield of 78%.

[0049] The embodiments described above are merely illustrative of several implementations of the present invention and should not be construed as limiting the scope of the present invention due to their detailed descriptions. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this patent should be determined by the appended claims.

Claims

1. A method for synthesizing allyl ether compounds III and IV, characterized in that: The reaction uses Selectfluor as a promoter, 2-methylquinoline I or other nitrogen heterocyclic compounds as reactants, or acetophenone derivative II as reactants, and dimethyl sulfoxide and ethyl acetate as reaction solvents, or dimethyl sulfoxide and propyl acetate as reaction solvents. The substituent R is: hydrogen, methyl, ethyl, propyl, isopropyl, methoxy, ethoxy, propoxy, phenoxy, fluorine, chlorine, bromine, nitro, trifluoromethyl, or cyano.

2. The method for synthesizing compound III according to claim 1, wherein the other nitrogen heterocyclic compounds are: 2-methyl-quinoxaline, 2-methyl-benzothiazole, and 1-methyl-isoquinoline.

3. The method for synthesizing compounds III and IV according to claim 1, with the following synthetic scheme claimed: 0.1 mmol (1.0 equivalent) of a 2-methylquinoline derivative or an acetophenone derivative is added to a 15 mL reaction tube, followed by the addition of a promoter, Selectfluor (0.2 mmol (2.0 equivalent), 1 mL of ethyl acetate or propyl acetate, and finally, 1 mL of dimethyl sulfoxide is slowly added. The reaction can be scaled up or scaled down according to the above ratio. The reaction tube containing the mixture is placed in an oil bath at 120 °C and magnetically stirred for 10 h. After the reaction is complete as monitored by TLC, the reaction solution is cooled to room temperature, an appropriate amount of water is added, and the mixture is extracted three times with ethyl acetate. The organic phase is collected, and an appropriate amount of anhydrous Na₂SO₄ is added to the combined organic layers for drying. The mixture is filtered, and the solvent is concentrated under reduced pressure. Using a mixture of petroleum ether and ethyl acetate as the mobile phase, the crude product is separated by silica gel column chromatography to obtain allyl ethyl ether or allyl propyl ether compounds.

Images