反应详情

At a bath temperature of +40° C., under argon and with exclusion of moisture, 582 mg (2.3 mmol) of 4-(2-amino-4-nitrophenylamino)benzoic acid ethyl ester is combined with 488 mg (4.8 mmol) of triethylamine in 27 ml of dry tetrahydrofuran. A solution of 659 mg (4.8 mmol) of oxalic acid ethyl ester chloride and 8 ml of dry tetrahydrofuran is added dropwise to this batch and stirred for 2 hours at room temperature. The mixture is then combined with 0.2 ml of triethylamine and 0.1 ml of oxalic acid ethyl ester chloride, and agitated for one hour at room temperature. The batch is filtered, and the filtrate is concentrated and distributed in water/ethyl acetate. The organic phase is concentrated. The residue is refluxed for 2 hours at the bath temperature in 25 ml of 1N hydrochloric acid and 25 ml of ethanol. The thus-precipitated product is suctioned off, washed with water, and dried, yielding 220 mg of 4-(6-nitro-2,3-dioxo-1,2,3,4-tetrahydroquinoxalin-1-yl)benzoic acid ethyl ester (further processed without purification).

1. stirringagitated for one hour at room temperature
2. filtrationThe batch is filtered
3. concentrationthe filtrate is concentrated
4. concentrationThe organic phase is concentrated
5. temperatureThe residue is refluxed for 2 hours at the bath temperature in 25 ml of 1N hydrochloric acid
6. washwashed with water
7. customdried