反应详情

温度

25 °C

The method of Skujins and Webb, Chem. Comm. 598 (1968), was used. Squaric acid (114 mg, 1.00 mmol; Aldrich Co.) was dissolved in hot water (2 mL) and o-phenylenediamine (108 mg, 1.00 mmol; Aldrich Co.) was dissolved in warm H2SO4 (2 mL, 25% w/v). The mixture was heated at 90°-100° C. for 2-3 min, and then allowed to cool to 25° C. The dark brown precipitate was collected by vacuum filtration and washed with water (10×5 mL), ethanol (10×5 mL), acetone (10×5 mL) and ether (10×5 mL), yielding 105 mg (56.5%): mp dec.>325° C. (lit. mp dec.>330° C.; Skujins and Webb, Chem. Comm. 598 (1968)). 1H NMR (300 MHz, DMSO-d6) δ 10.002 (s, 2H, 2 NH), 6.621-6.633 (m, 2H, H-4+H-7), 6.324-6.354 (m, 2H, H-5+H-6).

1. temperatureThe mixture was heated at 90°-100° C. for 2-3 min
2. filtrationThe dark brown precipitate was collected by vacuum filtration
3. washwashed with water (10×5 mL), ethanol (10×5 mL), acetone (10×5 mL) and ether (10×5 mL)
4. customyielding 105 mg (56.5%)
5. custom>325° C. (lit. mp dec.>330° C.; Skujins and Webb, Chem. Comm. 598 (1968))