反应详情

温度

100 °C

A solution of 5.4 g. of phenylglyoxal hydrate in 25 ml. water is treated with 50 ml. of aqueous sodium bisulfite (density 1.34) at 25° C. for 45 min. A solution of 3.9 g. of aminomalonamide in 39 ml. of water is added and the reaction mixture is heated at 100° C. for 2.5 hr. The resultant yellow precipitate which forms is isolated by filtration, washed with water, dried and recrystallized from ethanol to afford 3-hydroxy-5-phenylpyrazine-2-carboxamide. This product is hydrolyzed with saturated ethanolic sodium hydroxide for 16 hrs. at 150° C. to afford 3-hydroxy-5-phenylpyrazine-2-carboxylic acid. This product is refluxed with 30 ml. of carbitolacetate for 15 min. then cooled to 250° C. and petroleum ether (bp 68° C.) added to precipitate the title compound.

1. customThe resultant yellow precipitate which forms is isolated by filtration
2. washwashed with water
3. customdried
4. customrecrystallized from ethanol