2,5-dibromophenol

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:80.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of 2,5-dibromophenol (134) (1.26 g, 5 mmol) and 1,2-dibromoethane (135) (431 μl, 5 mmol) in 5 ml 1N NaOH was stirred at 80° C. for 40 h. After cooling down, the reaction mixture was extracted with diethyl ether. Org. phase was washed with 1 N NaOH and brine subsequently. Org. phase was dried over sodium sulfate concentrated to give 922 mg (yield 51%, purity ca 90%) 1,4-dibromo-2-(2-bromoethoxy)benzene (136) as orange-red oil which was used directly for further reaction without purification. After cooling down the reaction mixture was extracted with diethyl ether phase was washed with 1 N NaOH and brine subsequently phase was dried over sodium sulfate concentrated

Conditions: temp:80.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of 2,5-dibromophenol (134) (1.26 g, 5 mmol) and 1,2-dibromoethane (135) (431 μl, 5 mmol) in 5 ml 1N NaOH was stirred at 80° C. for 40 h. After cooling down, the reaction mixture was extracted with diethyl ether. Org. phase was washed with 1 N NaOH and brine subsequently. Org. phase was dried over sodium sulfate concentrated to give 922 mg (yield 51%, purity ca 90%) 1,4-dibromo-2-(2-bromoethoxy)benzene (136) as orange-red oil which was used directly for further reaction without purification. After cooling down the reaction mixture was extracted with diethyl ether phase was washed with 1 N NaOH and brine subsequently phase was dried over sodium sulfate concentrated

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

Procedure: 2,5-Dibromophenol (53 g) and benzyl 2-bromopropionate (48.6 g) in methyl iso-butyl ketone (250 ml) containing suspended potassium carbonate (13.8 g) was heated under reflux with stirring overnight. The mixture was cooled to 40°, 5% sodium hydroxide solution (100 ml) was added, and the mixture was stirred to dissolve the solid potassium bromide. The aqueous phase was separated with fresh methyl iso-butyl ketone (50 ml). The combined extracts were washed with water (50 ml), dried, and evaporated under reduced pressure. The residue was distilled and the benzyl (2,5-dibromophenoxy)propionate collected at 180°-185°/0.5 Torr. On cooling, the distillate solidified and had a melting point of 52° C. Compounds 1, 5, 6, 14 to 16, 18 to 20, 22 and 23 were made by a similar procedure. was heated under reflux The mixture was cooled to 40° the mixture was stirred The aqueous phase was separated with fresh methyl iso-butyl ketone (50 ml) The combined extracts were washed with water (50 ml) dried evaporated under reduced pressure The residue was distilled the benzyl (2,5-dibromophenoxy)propionate collected at 180°-185°/0.5 Torr On cooling

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

Procedure: 2,5-Dibromophenol (53 g) and benzyl 2-bromopropionate (48.6 g) in methyl iso-butyl ketone (250 ml) containing suspended potassium carbonate (13.8 g) was heated under reflux with stirring overnight. The mixture was cooled to 40°, 5% sodium hydroxide solution (100 ml) was added, and the mixture was stirred to dissolve the solid potassium bromide. The aqueous phase was separated with fresh methyl iso-butyl ketone (50 ml). The combined extracts were washed with water (50 ml), dried, and evaporated under reduced pressure. The residue was distilled and the benzyl (2,5-dibromophenoxy)propionate collected at 180°-185°/0.5 Torr. On cooling, the distillate solidified and had a melting point of 52° C. Compounds 1, 5, 6, 14 to 16, 18 to 20, 22 and 23 were made by a similar procedure. was heated under reflux The mixture was cooled to 40° the mixture was stirred The aqueous phase was separated with fresh methyl iso-butyl ketone (50 ml) The combined extracts were washed with water (50 ml) dried evaporated under reduced pressure The residue was distilled the benzyl (2,5-dibromophenoxy)propionate collected at 180°-185°/0.5 Torr On cooling

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:80.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of 2,5-dibromophenol (134) (1.26 g, 5 mmol) and 1,2-dibromoethane (135) (431 μl, 5 mmol) in 5 ml 1N NaOH was stirred at 80° C. for 40 h. After cooling down, the reaction mixture was extracted with diethyl ether. Org. phase was washed with 1 N NaOH and brine subsequently. Org. phase was dried over sodium sulfate concentrated to give 922 mg (yield 51%, purity ca 90%) 1,4-dibromo-2-(2-bromoethoxy)benzene (136) as orange-red oil which was used directly for further reaction without purification. After cooling down the reaction mixture was extracted with diethyl ether phase was washed with 1 N NaOH and brine subsequently phase was dried over sodium sulfate concentrated

Conditions: temp:80.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of 2,5-dibromophenol (134) (1.26 g, 5 mmol) and 1,2-dibromoethane (135) (431 μl, 5 mmol) in 5 ml 1N NaOH was stirred at 80° C. for 40 h. After cooling down, the reaction mixture was extracted with diethyl ether. Org. phase was washed with 1 N NaOH and brine subsequently. Org. phase was dried over sodium sulfate concentrated to give 922 mg (yield 51%, purity ca 90%) 1,4-dibromo-2-(2-bromoethoxy)benzene (136) as orange-red oil which was used directly for further reaction without purification. After cooling down the reaction mixture was extracted with diethyl ether phase was washed with 1 N NaOH and brine subsequently phase was dried over sodium sulfate concentrated

Conditions: temp:80.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of 2,5-dibromophenol (134) (1.26 g, 5 mmol) and 1,2-dibromoethane (135) (431 μl, 5 mmol) in 5 ml 1N NaOH was stirred at 80° C. for 40 h. After cooling down, the reaction mixture was extracted with diethyl ether. Org. phase was washed with 1 N NaOH and brine subsequently. Org. phase was dried over sodium sulfate concentrated to give 922 mg (yield 51%, purity ca 90%) 1,4-dibromo-2-(2-bromoethoxy)benzene (136) as orange-red oil which was used directly for further reaction without purification. After cooling down the reaction mixture was extracted with diethyl ether phase was washed with 1 N NaOH and brine subsequently phase was dried over sodium sulfate concentrated

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

Procedure: 61.6 Grams of 2,5-dibromoaniline and 250 g of 75% aqueous sulfuric acid solution were charged into a ceramic ball mill having one liter capacity. A suspension of fine particles of 2,5-dibromoaniline sulfate was prepared by a method similar to that described in Example 5. The suspension was transferred into a beaker having one liter capacity. The ceramic ball mill used was washed with 120 g of 75% aqueous sulfuric acid solution and the washings were transferred into the beaker. Diazotization of 2,5-dibromoaniline sulfate in the form of suspension of fine particles was carried out by a method similar to that described in Example 5 except that 18.2 g of sodium nitrite powder was added. Hydrolysis of 2,5-dibromobenzenediazonium sulfate was carried out by a method similar to that described in Example 5. A xylene layer was isolated from the hydrolyzed product and a crude product of 2,5-dibromophenol was obtained after the xylene was removed by distillation. The crude product of 2,5-dibromophenol was steam distilled by introducing superheated steam. After the distillate was cooled, crystallized 2,5-dibromophenol thus formed was obtained by filtration and dried. 47.3 Grams of 2,5-dibromophenol having melting point of 71°-74° C was obtained. The yield was found to be 85.0%. was prepared by a method similar to The ceramic ball mill used was washed with 120 g of 75% aqueous sulfuric acid solution Diazotization of 2,5-dibromoaniline sulfate in the form of suspension of fine particles was added Hydrolysis of 2,5-dibromobenzenediazonium sulfate