Reaktion #1129962

Reaktionsgleichung

hydrochloric acid

sodium nitrite

1-(2-Amino-4,5-dimethoxyphenyl)ethanone

HCl

→

6,7-Dimethoxycinnolin-4-ol

Lösungsmittel

water

Reaktionsbedingungen

Aufarbeitung

1. 1
   TemperaturThe reaction mixture was then heated to 60-70° C. for four hours
2. 2
   Sonstigea yellow solid formed
3. 3
   TemperaturAfter cooling the reaction mixture to 10° C.
4. 4
   Filtrationthe solid was collected by filtration
5. 5
   Sonstigeto give a brown solution
6. 6
   Sonstige6,7-Dimethoxycinnolin-4-ol precipitated as an off-white solid, which
7. 7
   Filtrationwas filtered
8. 8
   Waschenwashed with water (3×300 mL)
9. 9
   Sonstigedried in a vacuum overnight at 50° C.

Vorschrift

1-(2-Amino-4,5-dimethoxyphenyl)ethanone (105 g, 0.538 mol) was dissolved in concentrated HCl (2000 mL, 20 mol) at ambient temperature. The solution was then cooled to 0-4° C., and sodium nitrite (37.5 g, 0.543 mol) was added dropwise over 45 minutes as a solution in water (200 mL). The reaction mixture was stirred at 0-4° C. for one hour during which time it turned dark brown and became homogenous. The reaction mixture was then heated to 60-70° C. for four hours, and a yellow solid formed. After cooling the reaction mixture to 10° C., the solid was collected by filtration. The wet solid was suspended in 1500 mL of water, and the pH was adjusted to 12 with 4N NaOH to give a brown solution, followed by adjusting the pH to 7 with concentrated hydrochloric acid (78 mL). 6,7-Dimethoxycinnolin-4-ol precipitated as an off-white solid, which was filtered, washed with water (3×300 mL), and dried in a vacuum overnight at 50° C.

Quelle