Reaktion #3193

Reaktionsgleichung

HBr

1,2-dimethoxy-4,5-dinitrobenzene

→

product

1,2-Dihydroxy-4,5-dinitrobenzene

Lösungsmittel

acetic acid

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturthe reaction was slowly heated to reflux
2. 2
   Extraktionextracting the aqueous phase with CHCl3 (3×150 mL) in order
3. 3
   Sonstigeto remove any organic impurities
4. 4
   ExtraktionThe dinitro catechol was extracted out of the aqueous layer with ethyl acetate (3×150 mL)
5. 5
   WaschenThe combined ethyl acetate extracts were washed with water and brine (3×100 mL)
6. 6
   Trocknendried over MgSO4
7. 7
   Einengenconcentrated to an orange residue
8. 8
   workup.ADDITIONApproximately 100 mL of dichloromethane was added to the residue
9. 9
   workup.WAITplaced in the freezer for several hours
10. 10
    SonstigeThe light yellow needles that formed
11. 11
    Filtrationwere filtered
12. 12
    Waschenwashed with dichloromethane

Vorschrift

8B, FIG. 8. In a dry 500 mL round bottom flask, 1,2-dimethoxy-4,5-dinitrobenzene (3.2 g, 0.12 mmol) 8A was stirred vigorously in 40 mL of glacial acetic acid at 30° C. Once a homogeneous solution 200 mL of 48% HBr was added to the flask and the reaction was slowly heated to reflux. The reaction was complete as indicated by TLC after 4 hours. The work up involved pouring the cooled solution into 800 mL of ice water and then extracting the aqueous phase with CHCl3 (3×150 mL) in order to remove any organic impurities. The dinitro catechol was extracted out of the aqueous layer with ethyl acetate (3×150 mL). The combined ethyl acetate extracts were washed with water and brine (3×100 mL), then dried over MgSO4 and concentrated to an orange residue. Approximately 100 mL of dichloromethane was added to the residue and then placed in the freezer for several hours. The light yellow needles that formed were filtered and washed with dichloromethane to yield 2.37 g of product (84%). 1H NMR (d6 -acetone): δ3.45 (OH), 7.42 (Ar--H); 13C NMR (d6 -acetone): δ112.44, 137.00, 149.97, EI MS M+, 200.

Quelle