Sodium Hydroxide → N-[6-(n-butyl)-4H-1-benzothiopyran-4-on-3-yl)-oxalic acid monoamide

Participants

Reaction Steps

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).

Provenance & Evidence