反应详情

4-Amino-3-methylbenzonitrile (1.94 g, 14.7 mmol) was added to a solution of 3,4-diethoxy-3-cyclobutene-1,2-dione (2.53 g, 14.9 mmol) in acetonitrile (5 mL). After refluxing the mixture for 24 h a second portion of 3,4-diethoxy-3-cyclobutene-1,2-dione (1.15 g, 6.76 mmol) was added and heating was continued for an additional 48 h. The reaction mixture was diluted with ethyl acetate (50 mL), stirred vigorously and filtered free of undissolved solid. The filtrate was chromatographed (CH3OH/CH2Cl2) to afford 0.90 g (24%) of product as a yellow solid: 1H NMR (DMSO-d6): δ 10.50 (s, 1H), 7.76-7.63 (m, 2H), 7.31 (d, 1H), 4.71 (q, 2H), 2.33 (s, 3H), 1.38 (t, 3H).

1. additionwas added
2. temperatureheating
3. filtrationfiltered free of undissolved solid
4. customThe filtrate was chromatographed (CH3OH/CH2Cl2)