反应详情

Formic acid (2 ml) was added to a solution of amine 8a (0.10 g, 0.4 mmole) in ethyl formate (previously distilled over calcium hydride) (8 ml). The mixture was heated under reflux for 12 hours. After evaporation of the volatile substances, the residue was washed twice with ethanol and once with ethyl acetate. It was purified by column chromatography using a mixture of dichloromethane and ethanol (95:5) as eluant and, at the end, ethyl acetate, to give compound 11a (0.06 g, 58%) in the form of a white powder: melting point 221-222° C.; NMR-1H (DMSO-d6) δ 11.96 (1H, s, NH-1), 8.28 (1H, s, NH-3) 7.23 (1H, s, H-6), 6.88 (1H, d, H-4'), 6.78 (2H, s, H-2' and 6'), 2.23 (6H, s, CH3 -3' and 5'), 1.85 (3H, s, CH3 -5). Anal. C15H16N2O2S (C, H, N, S).

1. distillationpreviously distilled over calcium hydride) (8 ml)
2. temperatureThe mixture was heated
3. temperatureunder reflux for 12 hours
4. customAfter evaporation of the volatile substances
5. washthe residue was washed twice with ethanol and once with ethyl acetate
6. customIt was purified by column chromatography
7. additiona mixture of dichloromethane and ethanol (95:5) as eluant