4,5-difluoro-2-methylphenol

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

Procedure: 214 g of 4,5-difluoro-2-hydroxy-N,N-dimethylbenzylamine are initially charged in 700 ml of acetic acid in an autoclave, admixed with 50 g of palladium/activated carbon (5%) and heated with 70 bar of hydrogen to 100° C. for 26 hours. The autoclave is cooled and decompressed. The catalyst is filtered off and washed with acetic acid, and the filtrate is admixed with 3 000 ml of water. This aqueous solution is extracted three times with methyl tert-butyl ether. The combined organic phases are washed once with water and dried, and the solvent is distilled off under reduced pressure. The crude product is fractionally distilled under reduced pressure. The distillate can be further purified by crystallization. 98 g (58% of theory) of a colourless solid are obtained having a melting point of 68-70° C. and a boiling point of 78-80° C. at 13 mbar. The autoclave is cooled The catalyst is filtered off washed with acetic acid This aqueous solution is extracted three times with methyl tert-butyl ether The combined organic phases are washed once with water dried the solvent is distilled off under reduced pressure The crude product is fractionally distilled under reduced pressure The distillate can be further purified by crystallization 98 g (58% of theory) of a colourless solid are obtained

Conditions: temp:98.51; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 30 g of 4,5-difluoro-2-methylphenol are dissolved in 180 ml of trifluoroacetic acid and admixed with 57.2 g of hexamethylenetetramine in portions. On completion of addition, the reaction solution is heated to 97-100° C. for 4 hours. After cooling, first 60 ml of 50% sulphuric acid and then 300 ml of water are added dropwise, then the solution is stirred further at room temperature for 2 hours. The reaction solution is extracted three times with methyl tert-butyl ether. The combined extracts are washed once with water and dried, and the solvent is distilled off under reduced pressure. The residue is extracted repeatedly with n-hexane, the extracts are combined and the solvent is distilled off under reduced pressure. 12.5 g (33% of theory) of a bright yellow solid are obtained having a melting point of 53-56° C. On completion of addition After cooling The reaction solution is extracted three times with methyl tert-butyl ether The combined extracts are washed once with water dried the solvent is distilled off under reduced pressure The residue is extracted repeatedly with n-hexane the solvent is distilled off under reduced pressure 12.5 g (33% of theory) of a bright yellow solid are obtained

Conditions: temp:98.51; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 30 g of 4,5-difluoro-2-methylphenol are dissolved in 180 ml of trifluoroacetic acid and admixed with 57.2 g of hexamethylenetetramine in portions. On completion of addition, the reaction solution is heated to 97-100° C. for 4 hours. After cooling, first 60 ml of 50% sulphuric acid and then 300 ml of water are added dropwise, then the solution is stirred further at room temperature for 2 hours. The reaction solution is extracted three times with methyl tert-butyl ether. The combined extracts are washed once with water and dried, and the solvent is distilled off under reduced pressure. The residue is extracted repeatedly with n-hexane, the extracts are combined and the solvent is distilled off under reduced pressure. 12.5 g (33% of theory) of a bright yellow solid are obtained having a melting point of 53-56° C. On completion of addition After cooling The reaction solution is extracted three times with methyl tert-butyl ether The combined extracts are washed once with water dried the solvent is distilled off under reduced pressure The residue is extracted repeatedly with n-hexane the solvent is distilled off under reduced pressure 12.5 g (33% of theory) of a bright yellow solid are obtained

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

Procedure: 214 g of 4,5-difluoro-2-hydroxy-N,N-dimethylbenzylamine are initially charged in 700 ml of acetic acid in an autoclave, admixed with 50 g of palladium/activated carbon (5%) and heated with 70 bar of hydrogen to 100° C. for 26 hours. The autoclave is cooled and decompressed. The catalyst is filtered off and washed with acetic acid, and the filtrate is admixed with 3 000 ml of water. This aqueous solution is extracted three times with methyl tert-butyl ether. The combined organic phases are washed once with water and dried, and the solvent is distilled off under reduced pressure. The crude product is fractionally distilled under reduced pressure. The distillate can be further purified by crystallization. 98 g (58% of theory) of a colourless solid are obtained having a melting point of 68-70° C. and a boiling point of 78-80° C. at 13 mbar. The autoclave is cooled The catalyst is filtered off washed with acetic acid This aqueous solution is extracted three times with methyl tert-butyl ether The combined organic phases are washed once with water dried the solvent is distilled off under reduced pressure The crude product is fractionally distilled under reduced pressure The distillate can be further purified by crystallization 98 g (58% of theory) of a colourless solid are obtained

Conditions: temp:98.51; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 30 g of 4,5-difluoro-2-methylphenol are dissolved in 180 ml of trifluoroacetic acid and admixed with 57.2 g of hexamethylenetetramine in portions. On completion of addition, the reaction solution is heated to 97-100° C. for 4 hours. After cooling, first 60 ml of 50% sulphuric acid and then 300 ml of water are added dropwise, then the solution is stirred further at room temperature for 2 hours. The reaction solution is extracted three times with methyl tert-butyl ether. The combined extracts are washed once with water and dried, and the solvent is distilled off under reduced pressure. The residue is extracted repeatedly with n-hexane, the extracts are combined and the solvent is distilled off under reduced pressure. 12.5 g (33% of theory) of a bright yellow solid are obtained having a melting point of 53-56° C. On completion of addition After cooling The reaction solution is extracted three times with methyl tert-butyl ether The combined extracts are washed once with water dried the solvent is distilled off under reduced pressure The residue is extracted repeatedly with n-hexane the solvent is distilled off under reduced pressure 12.5 g (33% of theory) of a bright yellow solid are obtained