2,4-difluoro-1-methylbenzene

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

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

Procedure: DE-A 2,333,849 discloses that 2,4-difluorobenzaldehyde can be converted into 2,4-difluorobenzyl alcohol in a yield of 68.6% by hydrogenation over Raney nickel. Disadvantages of this process are not only the large amount of catalyst (31 g per mol) and the large amount of a solvent (1100 ml per mole) but also the unsatisfactory yield of 68.6%. These factors result in an unsatisfactory space-time yield. The aldehyde used was obtained here from the difficult-to-obtain 2,4-difluorotoluene by side-chain chlorination and subsequent hydrolysis. These factors result in an unsatisfactory space-time yield

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

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

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

Procedure: DE-A 2,333,849 discloses that 2,4-difluorobenzaldehyde can be converted into 2,4-difluorobenzyl alcohol in a yield of 68.6% by hydrogenation over Raney nickel. Disadvantages of this process are not only the large amount of catalyst (31 g per mol) and the large amount of a solvent (1100 ml per mole) but also the unsatisfactory yield of 68.6%. These factors result in an unsatisfactory space-time yield. The aldehyde used was obtained here from the difficult-to-obtain 2,4-difluorotoluene by side-chain chlorination and subsequent hydrolysis. These factors result in an unsatisfactory space-time yield

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

Procedure: DE-A 2,333,849 discloses that 2,4-difluorobenzaldehyde can be converted into 2,4-difluorobenzyl alcohol in a yield of 68.6% by hydrogenation over Raney nickel. Disadvantages of this process are not only the large amount of catalyst (31 g per mol) and the large amount of a solvent (1100 ml per mole) but also the unsatisfactory yield of 68.6%. These factors result in an unsatisfactory space-time yield. The aldehyde used was obtained here from the difficult-to-obtain 2,4-difluorotoluene by side-chain chlorination and subsequent hydrolysis. These factors result in an unsatisfactory space-time yield

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

Procedure: Chlorosulfonic acid (5.2 mL, 0.078 mol) was added dropwise to a solution of 2,4-difluorotoluene (4.00 g, 0.0312 mol) in chloroform (75 mL, 0.94 mol). The reaction was stirred 2 hours. Additional chlorosulfonic acid (3.1 mL, 0.047 mol) was added and stirring was continued for 18 hours. The reaction was evaporated to an oil and poured onto ice. The mixture was extracted two times with ethyl ether. The combined organic phase was dried over magnesium sulfate and treated with activated carbon. The mixture was filtered through diatomaceous earth and the filtrate was evaporated to give 5.31 g of light brown oil. stirring was continued for 18 hours The reaction was evaporated to an oil poured onto ice The mixture was extracted two times with ethyl ether The combined organic phase was dried over magnesium sulfate treated with activated carbon The mixture was filtered through diatomaceous earth the filtrate was evaporated

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

Procedure: Chlorosulfonic acid (5.2 mL, 0.078 mol) was added dropwise to a solution of 2,4-difluorotoluene (4.00 g, 0.0312 mol) in chloroform (75 mL, 0.94 mol). The reaction was stirred 2 hours. Additional chlorosulfonic acid (3.1 mL, 0.047 mol) was added and stirring was continued for 18 hours. The reaction was evaporated to an oil and poured onto ice. The mixture was extracted two times with ethyl ether. The combined organic phase was dried over magnesium sulfate and treated with activated carbon. The mixture was filtered through diatomaceous earth and the filtrate was evaporated to give 5.31 g of light brown oil. stirring was continued for 18 hours The reaction was evaporated to an oil poured onto ice The mixture was extracted two times with ethyl ether The combined organic phase was dried over magnesium sulfate treated with activated carbon The mixture was filtered through diatomaceous earth the filtrate was evaporated

Conditions: temp:45.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a stirred solution of 2,4-difluorotoluene (25.0 g, 195.3 mmol) in conc. H2SO4 (60 mL) was added fuming HNO3 (30 mL) drop wise at the rate that temperature was maintained between 40-50° C. over a period of 1.5 h. The reaction mixture was stirred at 40° C. for an additional 1 h. The reaction mixture was poured into ice-cold water (500 mL) and the solid precipitated was filtered and washed with water (2×50 mL). The solid residue was dissolved in EtOAc (200 mL), washed with aq. NaHCO3 (2×200 mL). The organic layer was dried over Na2SO4, filtered and evaporated in vacuo to afford 1,5-difluoro-2-methyl-3-nitrobenzene (21.0 g, 62%) as a light brown liquid. the solid precipitated was filtered washed with water (2×50 mL) The solid residue was dissolved in EtOAc (200 mL) washed with aq. NaHCO3 (2×200 mL) The organic layer was dried over Na2SO4 filtered evaporated in vacuo