preparation method | 1. Dissolve 10 grams of 2-methyl-3-nitrotrifluoromethyl benzene in 70 ml of methanol; under the protection of nitrogen, add 5 grams of palladium and carbon to the above solution, and replace it with hydrogen three times. Stir overnight at room temperature. Filtration, filter drying, solid product A2.6g, yield 30.37%. TLC information (PE: EA = 5: 1): raw material Rf = 0.69, product Rf = 0.30. II. Dissolve 0.5 grams of A in 22ml of acetic acid, reflux, add 4.77 grams of bromine to the mixed solution and dissolve in 15 ml of acetic acid solution. Stir for 2 hours and the reaction is complete. Pour the reaction solution into ice water, adjust PH8 ~ 9 with saturated sodium bicarbonate, extract with ethyl acetate, and purify through column. The product B is 3.2g, and the yield is 39.4%. 1H-NMR(CDCl3;400MHZ):7.382(d,1H);6.920(d,1H) 3. Dissolve B in 500ml chloroform, cool in an ice bath, add 2.65 grams of potassium acetate and 2.65 grams of acetic anhydride to the above solution in turn, remove the ice bath after 5 minutes, and naturally return to room temperature. After 1 hour, the reaction is complete. Add 3.35g isoamyl nitrite and 0.69g 18-crown ether -6, and heat and reflux overnight. The reaction is complete, chloroform is rotated, H2O: EA = 1: 1(300ml) is added to dissolve it, EA extracts the aqueous phase three times, anhydrous magnesium sulfate is dried, 324 ml MeOH and 45.81g potassium carbonate are added to the crude product, and TLC detects that there is no acetyl product. The system is concentrated and the product is obtained through the column. The product was 1.95G, and the yield was 55.36%. |