Reaktion #2075743

Reaktionsgleichung

HCl

sodium nitrite

2-Amino-3-nitrophenol

HCl

→

2-chloro-3-nitrophenol

Ausbeute 48.0%

Lösungsmittel

H2O

1,4-dioxane

H2O

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.ADDITIONwas added over a period of 3 hours to the brown solution
2. 2
   TemperaturThe temperature was maintained below 10° C. during the addition
3. 3
   Temperaturwarmed to 60° C.
4. 4
   workup.STIRRINGstirred for an additional 15 min The reaction mixture
5. 5
   Sonstigewas then brought to room temperature
6. 6
   workup.WAITleft
7. 7
   workup.STIRRINGto stir overnight
8. 8
   SonstigeThe reaction mixture was transferred to a separatory funnel
9. 9
   Extraktionextracted with ether (3×150 mL)
10. 10
    Waschenwashed with brine (1×)
11. 11
    Trocknendried (Na2SO4)
12. 12
    Filtrationfiltered
13. 13
    Einengenconcentrated
14. 14
    Sonstigeto afford the crude product (5.83 g) as a red-brown oil
15. 15
    SonstigeThe crude material was purified by flash column chromatography (1:25 ultra pure silica gel, 230-400 mesh, 40-60 mm, 60 angstroms

Vorschrift

2-Amino-3-nitrophenol B1 (5 g; 32.4 mmol) was dissolved in concentrated HCl (75 mL) and 1,4-dioxane (14.7 mL). The mixture was heated to 70° C. until most of the solids were in solution. The reaction mixture was cooled to 0° C. (ice bath), and sodium nitrite (2.23 g; 32.3 mmol) in H2O (5.4 mL) was added over a period of 3 hours to the brown solution. The temperature was maintained below 10° C. during the addition and the stirring was continued for an additional 15 min at 0° C. This diazonium intermediate was poured into a solution of Cu(I)Cl (3.8 g; 38.9 mmol) in H2O (18.5 mL) and conc. HCl (18.5 mL) at 0° C. The reaction was stirred for 15 min at 0° C., warmed to 60° C., and stirred for an additional 15 min The reaction mixture was then brought to room temperature, and left to stir overnight. The reaction mixture was transferred to a separatory funnel and extracted with ether (3×150 mL). The organic layers were combined, washed with brine (1×), dried (Na2SO4), filtered and concentrated to afford the crude product (5.83 g) as a red-brown oil. The crude material was purified by flash column chromatography (1:25 ultra pure silica gel, 230-400 mesh, 40-60 mm, 60 angstroms; 3:1 hexane/EtOAcas the solvent) to afford pure 2-chloro-3-nitrophenol C2 (48%; 2.7 g) as an orange solid.

Quelle