反应详情

A solution of 14 (3.0 g, 17 mmol), trifluoroacetic acid (2 ml, 28 mmol) and trifluoroacetic anhydride (4 ml, 28 mmol) in CH2Cl2 is refluxed for 15 minutes, cooled, and the mixture is poured onto ice, extracted twice with CH2Cl2 and evaporated. The mixture is chromatographed on silica gel to give 4.5 g of compound 15 (94% yield). 1H NMR [300 MHz, (CD3)2SO], a 3:2 mixture of amide conformers doubling most signals, δ 11.24 (0.8H, s, NH), 11.21 (1.2H, s, NH), 7.55-7.40 (2H, m, H5.8), 7.22 (0.6H, s, H-6), 7.20 (0.4H, s, H-6), 4.64 (0.8H, s, ArCH2N), 4.57 (1.2H, s, ArCH2N), 3.65 (2H, t, ArCH2CH2N), 2.84 (1.2H, t, ArCH2CH2N), 2.73 (0.8H, t, ArCH2CH2N), 2.06 (1.2H, s, COCH3), 2.05 (1.8H, s COCH3).

1. temperaturecooled
2. additionthe mixture is poured onto ice
3. extractionextracted twice with CH2Cl2
4. customevaporated
5. customThe mixture is chromatographed on silica gel