反应详情

1,2,3,4-Tetrahydro-8-methoxy-5H-[1]benzopyrano[3,4-c]pyridin-5-one (1.0 g) is dissolved in a mixture of concentrated sulfuric acid (3 ml) and water (2 ml). The resulting solution is cooled in an ice bath and concentrated nitric acid (1 ml) is added. The reaction mixture is stirred at room temperature for 20 hours. The reaction mixture is poured over ice and made basic with aqueous ammonium hydroxide solution. The product is filtered off and washed with water. Recrystallization from ethanol gave the product (535 mg), mp 200°-205° C. (dec.).

1. temperatureThe resulting solution is cooled in an ice bath
2. additionThe reaction mixture is poured over ice
3. filtrationThe product is filtered off
4. washwashed with water
5. customRecrystallization from ethanol