Trifluoromethyl substituted benzofuran derivatives and preparation method thereof
A technology of benzofuran and trifluoromethyl, which is applied in the field of trifluoromethyl-substituted benzofuran derivatives and its preparation, can solve problems such as poor yield and selectivity, harsh reaction conditions, and few synthetic studies , to achieve high yield, mild synthesis conditions and simple synthesis steps
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Embodiment 1
[0020] The general structural formula is I, wherein, R 1 , R 2 , R 3 Preparation of the benzofuran derivative of H, 2-trifluoromethylbenzofuran.
[0021] Dissolve 1 mL of the compound salicylaldehyde in 10 mL of N,N-dimethylformamide, under nitrogen balloon protection, at room temperature, add 3.25 g of zinc powder, 2.8 mL of acetic anhydride, stir, and dropwise add 1, 1,1-Trichloro-2,2,2-Trifluoroethane 3.6mL, after dropwise addition, continue to react for 3 hours, add 50mL saturated ammonium chloride solution and 50mL ethyl acetate, separate liquid, extract with ethyl acetate The aqueous layer was collected and the organic phase was concentrated to obtain a dark brown liquid, which was separated and purified by flash column chromatography using petroleum ether as an eluent to obtain 1.32 g of a light brown liquid with a yield of 50%. Dissolve this compound in 5mL of N,N-dimethylformamide, add 1.68g of potassium tert-butoxide at room temperature, react for 3 hours, add 25m...
Embodiment 2
[0024] The general structural formula is I, wherein, R 1 for CH 3 , R 2 , R 3 Preparation of the benzofuran derivative 5-methyl-2-trifluoromethylbenzofuran as H.
[0025] Dissolve 1.36g of the compound 5-methyl salicylaldehyde in 10mL of N,N-dimethylformamide, under nitrogen balloon protection, at room temperature, add 3.25g of zinc powder, 3.0mL of acetic anhydride, stir, and add Add dropwise 3.6mL of 1,1,1-trichloro-2,2,2-trifluoroethane, after the dropwise addition, react for 3 hours, add 50mL of saturated ammonium chloride solution and 50mL of ethyl acetate, separate liquid, acetic acid The aqueous layer was extracted with ethyl ester, the organic phase was collected and concentrated, and the resulting brown liquid was separated and purified by flash column chromatography using petroleum ether as an eluent to obtain 1.25 g of a light brown liquid with a yield of 45%. Dissolve this compound in 5mL of N,N-dimethylformamide, add 1.57g of potassium tert-butoxide at room te...
Embodiment 3
[0028] The general structural formula is I, wherein, R 1 for Cl, R 2 , R 3 Preparation of the benzofuran derivative of H, 2-trifluoromethyl-5-chlorobenzofuran.
[0029] Dissolve 1.57g of the compound 5-chlorosalicylaldehyde in 10mL of N,N-dimethylformamide, under nitrogen balloon protection, at room temperature, add 3.51g of zinc powder, 3.7mL of acetic anhydride, stir, and dropwise add 1,1,1-Trichloro-2,2,2-Trifluoroethane 4.0mL, after the dropwise addition, react for 4 hours, add 50mL saturated ammonium chloride solution and 50mL ethyl acetate, separate liquid, ethyl acetate The aqueous layer was extracted, the organic phase was collected and concentrated, and the obtained brown liquid was separated and purified by flash column chromatography using petroleum ether as an eluent to obtain 1.31 g of a light yellow solid with a yield of 44%. Dissolve this compound in 5mL of N,N-dimethylformamide, add 1.48g of potassium tert-butoxide at room temperature, react for 3 hours, add...
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