反应详情

温度

-5 °C

Concentrated hydrochloric acid (8 ml) is added to a stirred suspension of 9-amino-1,2,3,4-tetrahydro-8-methyl-5H-[1]benzopyrano[3,4-c]pyridin-5-one (1.5 g, 0.0065 moles) in water (5 ml). The solution is cooled to -5° C. and a solution of sodium nitrite (0.45 g, 0.0065 moles) in water (4 ml) is added dropwise. After 15 minutes the mixture is added to a solution of freshly prepared cuprous chloride (0.8 g, 0.008 moles) in 20% HCl (8 ml) and stirred for 15 minutes. The suspension is warmed on the steam bath for one hour, allowed to cool, and 10% aqueous potassium carbonate is added until the mixture is basic. The precipitate is filtered off, rinsed with water, dissolved in warm dilute hydrochloric acid, filtered, and reprecipitated by the addition of concentrated ammonium hydroxide. The precipiate is filtered off, rinsed with water, and dried. Recrystallization from ethyl acetate gave the product (0.8 g), mp 184°- 185° C.

1. temperatureThe suspension is warmed on the steam bath for one hour
2. temperatureto cool
3. filtrationThe precipitate is filtered off
4. washrinsed with water
5. dissolutiondissolved
6. temperaturein warm dilute hydrochloric acid
7. filtrationfiltered
8. customreprecipitated by the addition of concentrated ammonium hydroxide
9. filtrationThe precipiate is filtered off
10. washrinsed with water
11. customdried
12. customRecrystallization from ethyl acetate