2-amino-4,6-dibromophenol

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 2-Bromo-6-nitrophenol (1.506 g, 0.0057 mol, containing 2,4-di-bromo-6-nitrophenol, 18% w/w) and sodium hydrosulfite (3.05 g, 85%, 0.015 mol) were heated at reflux in ethanol/water (50 ml of a 5:1 v/v mixture). After 2 hours, the reaction mixture was diluted with water (150 ml) and extracted with dichloromethane (3×50 ml), and ethyl acetate (100 ml). The organic extracts were combined, dried over calcium sulfate, evaporated in vacuo, and purified by flash chromatography (SiO2, petrol/ether 1:1 v/v) to furnish a mixture of the title compound and 6-amino-2,4-di-bromophenol (0.600 g, of a 76:24 w/w mixture as judged by 1 H-NMR). Yield 6-amino-2-bromophenol, 43%. extracted with dichloromethane (3×50 ml), and ethyl acetate (100 ml) dried over calcium sulfate evaporated in vacuo purified by flash chromatography (SiO2, petrol/ether 1:1 v/v) to furnish

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 44.2 g. of 2-amino-4,6-dibromo-phenol were processed with 85.5 ml. of acetic anhydride keeping the temperature under 50° C. By cooling, the 2-acetylamino-4,6-dibromo-phenol separated; it was collected on a filter and crystallized from ethyl alcohol. 30 g. of pure product were obtained. M.P. = 175°-176° C. under 50° C By cooling the 2-acetylamino-4,6-dibromo-phenol separated it was collected on a filter crystallized from ethyl alcohol of pure product were obtained

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 44.2 g. of 2-amino-4,6-dibromo-phenol were processed with 85.5 ml. of acetic anhydride keeping the temperature under 50° C. By cooling, the 2-acetylamino-4,6-dibromo-phenol separated; it was collected on a filter and crystallized from ethyl alcohol. 30 g. of pure product were obtained. M.P. = 175°-176° C. under 50° C By cooling the 2-acetylamino-4,6-dibromo-phenol separated it was collected on a filter crystallized from ethyl alcohol of pure product were obtained

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of 89 g. of 2-nitro-4,6-dibromo-phenol, 270 ml. of methyl alcohol, 50ml. of 30% NaOH aqueous solution and 2,400 ml. of demineralized water was heated up to 50°-55° C., obtaining a yellow solution. To this solution, 178 g. of Na2S2O3 were added in small portions, by keeping the temperature at 50° C. The reaction mixture was then stirred for 30 minutes by keeping the temperature at 65° C. and finally for 30 minutes at room temperature. By cooling, 44.2 g. of 2-amino-4,6-dibromo-phenol were obtained, having a melting point equal to 89°-92° C. A mixture of 89 g obtaining a yellow solution at 50° C at 65° C. finally for 30 minutes at room temperature By cooling

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of 89 g. of 2-nitro-4,6-dibromo-phenol, 270 ml. of methyl alcohol, 50ml. of 30% NaOH aqueous solution and 2,400 ml. of demineralized water was heated up to 50°-55° C., obtaining a yellow solution. To this solution, 178 g. of Na2S2O3 were added in small portions, by keeping the temperature at 50° C. The reaction mixture was then stirred for 30 minutes by keeping the temperature at 65° C. and finally for 30 minutes at room temperature. By cooling, 44.2 g. of 2-amino-4,6-dibromo-phenol were obtained, having a melting point equal to 89°-92° C. A mixture of 89 g obtaining a yellow solution at 50° C at 65° C. finally for 30 minutes at room temperature By cooling

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 2-Bromo-6-nitrophenol (1.506 g, 0.0057 mol, containing 2,4-di-bromo-6-nitrophenol, 18% w/w) and sodium hydrosulfite (3.05 g, 85%, 0.015 mol) were heated at reflux in ethanol/water (50 ml of a 5:1 v/v mixture). After 2 hours, the reaction mixture was diluted with water (150 ml) and extracted with dichloromethane (3×50 ml), and ethyl acetate (100 ml). The organic extracts were combined, dried over calcium sulfate, evaporated in vacuo, and purified by flash chromatography (SiO2, petrol/ether 1:1 v/v) to furnish a mixture of the title compound and 6-amino-2,4-di-bromophenol (0.600 g, of a 76:24 w/w mixture as judged by 1 H-NMR). Yield 6-amino-2-bromophenol, 43%. extracted with dichloromethane (3×50 ml), and ethyl acetate (100 ml) dried over calcium sulfate evaporated in vacuo purified by flash chromatography (SiO2, petrol/ether 1:1 v/v) to furnish