反应详情

6.15 g (0.0193 mol) of N-[6-(n-butyl)-4H-1-benzothiopyran-4-on-3-yl]-oxamide methyl ester are stirred with a solution of 22.6 ml of 1N sodium hydroxide solution in 147 ml of ethanol and 970 ml of water for 2 hours at 70°. A small degree of cloudiness is then removed by filtration and the filtrate is acidified with hydrochloric acid, a crystalline product being precipitated. After cooling, the crystals are filtered with suction and washed first with water, then with ethanol and subsequently with ether. After drying there is obtained N-[6-(n-butyl)-4H-1-benzothiopyran-4-on-3-yl)-oxalic acid monoamide having a melting point of 208° (decomposition).

1. customA small degree of cloudiness is then removed by filtration
2. customa crystalline product being precipitated
3. temperatureAfter cooling
4. filtrationthe crystals are filtered with suction
5. washwashed first with water
6. customAfter drying there