2,3-Difluoro-4-hydroxybenzonitrile

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

Procedure: A mixture of 0.12 mole of p-pentylbenzyl chloride and 20 ml of ethanol is added to a mixture of 0.1 mole of 2,3-difluoro-4-cyanophenol (prepared as in Example 1) and 0.1 mole of sodium ethoxide in 60 ml of ethanol, and the mixture is heated at the boil for 5 hours. After the ethanol has been distilled off, the reaction mixture is allowed to cool and is poured onto 15 ml of 5% aqueous sodium hydroxide solution. Working up in the customary manner gives 4-(4-pentylbenzyloxy)-2,3-difluorobenzonitrile. the mixture is heated at the boil for 5 hours After the ethanol has been distilled off to cool is poured onto 15 ml of 5% aqueous sodium hydroxide solution

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

Procedure: A mixture of 0.1 mole of trans-4-octylcyclohexanecarbonyl chloride (prepared from the carboxylic acid with oxalyl chloride in toluene) and 75 ml of methylene dichloride is added to a mixture of 0.1 mole of 2,3-difluoro-4-cyanophenol (prepared as in Example 1), 0.12 mole of pyridine, 10 mmole of 4-N,N-dimethylaminopyridine and 250 ml of methylene dichloride. After being stirred for 10 hours at room temperature, the mixture is washed with dilute hydrochloric acid, saturated sodium bicarbonate solution and water. Working up in the customary manner gives 4-(trans-4-octylcyclohexanecarbonyloxy)-2,3-difluorobenzonitrile. the mixture is washed with dilute hydrochloric acid, saturated sodium bicarbonate solution and water

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

Procedure: A mixture of 0.11 mole of dicyclohexylcarbodimide and 20 ml of toluene is added to a mixture of 0.1 mole of p-pentylbenzoic acid, 0.1 mole of 2,3-difluoro-4-cyanophenol (prepared as in Example 1), 1.5 g of 4-N,N-dimethylaminopyridine and 200 ml of toluene. After stirring for 4 hours at room temperature 0.4 g of oxalic acid is added to the mixture and stirring is continued for 30 minutes. Working up i the customary manner gives 4-(4-penylbenzoyloxy)-2,3-difluorobenzonitrile. is added to the mixture

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

Procedure: A mixture of 0.1 mole of 4-ethoxy-2,3-difluorobenzonitrile, 0.12 mole of aluminium chloride and 150 ml of toluene is heated at the boil for 2 hours. Working up in the customary manner gives the phenol in the form of a colourless solid. is heated at the boil for 2 hours

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

Procedure: A solution of 0.1 mol of 4-ethoxy-2,3-difluoro benzonitrile in 100 ml of toluene is slowly added dropwise at room temperature in the course of 30 minutes to a solution of 0.1 mol of aluminium(III) chloride in 100 ml of toluene. The mixture is subsequently heated to boiling for 5 hours and worked up as customary after cooling, m.p.: 145° C. The mixture is subsequently heated after cooling

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

Procedure: A mixture of 0.1 mol of trans-4-octylcyclohexanecarbonyl chloride (prepared from the carboxylic acid with oxalyl chloride in toluene) and 75 ml of methylene chloride is added to a mixture of 0.1 mol of 2,3-difluoro-4-cyanophenol (prepared according to Example 4), 0.12 mol of pyridine, 10 mmol of 4-N,N-dimethylaminopyridine and 250 ml of methylene chloride. After the mixture has been stirred at room temperature for 10 hours, it is washed with dilute hydrochloric acid, saturated sodium bicarbonate solution and water. Customary working up gives 4-(trans-4-octylcyclohexanecarbonyloxy)-2,3-difluorobenzonitrile. it is washed with dilute hydrochloric acid, saturated sodium bicarbonate solution and water

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

Procedure: A mixture of 0.11 mol of dicyclohexylcarbodiimide and 20 ml of toluene is added to a mixture of 0.1 mol of p-pentylbenzoic acid, 0.1 mol of 2,3-difluoro-4-cyanophenol (prepared according to Example 4), 1.5 g of 4-N,N-dimethylaminopyridine and 200 ml of toluene. After the mixture has been stirred at room temperature for 4 hours, 0.4 g of oxalic acid is added and stirring is continued for a further 30 minutes. Customary working up gives 4-(4-pentylbenzoyloxy)-2,3-difluorobenzonitrile, mp. 33° C. stirring is continued for a further 30 minutes

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

Procedure: A mixture of 2,3-difluoro-4-cyanophenol (1 g, 6.45 mmol) in water (8 mL), H2SO4 (8 mL), and acetic acid (8 mL) was refluxed for 48 hours. The solvents were removed by rotary evaporation to give a slurry which was poured onto ice. The product precipitated out of solution and filtered. The solid was washed with water and dried to give 2,3-difluoro-4-hydroxybenzoic acid (800 mg, 71%). was refluxed for 48 hours The solvents were removed by rotary evaporation to give a slurry which was poured onto ice The product precipitated out of solution filtered The solid was washed with water dried