2,6-Lutidine → 1,4-Difluoro-2-(isocyano(tosyl)methyl)benzene

Participants

Reaction Conditions

Reaction Steps

To a clean a dry nitrogen purged acetone boiled out 100 gallon glass lined reactor was charged, 7.9 Kg of N-[(2,5-Difluoro-phenyl)-(toluene-4-sulfonyl)-methyl]-formamide (24, moles), 16 gallons of tetrahydrofuran and 7.8 Kg of phosphorous oxychloride (51 moles). The batch was allowed to stir at 20° C. for 30 minutes and then cooled to 3.5° C. To the batch was added 15.8 Kg of 2,6-lutidine (146 moles) over 15 minutes. The reaction mixture was allowed to warm to 23° C. and was stirred for 17 hours at 23° C. The reaction was judged complete by HPLC and was charged to a 40 gallon solution of 10% sodium bicarbonate at 22° C., and the contents were allowed to stir for 30 minutes. To the batch was then added 25 gallons of ethyl acetate and the layers were separated. The water layer was backwashed with 9 gallons of ethyl acetate and the product rich ethyl acetate combined with the first wash. The product rich ethyl acetate layers were added to a 10% citric acid solution (20 gallons) and then stirred. The organic layer was checked by HPLC for 2,6 lutidine and then separated. The organic layer was washed with 10 gallons of saturated NaCl and dried over 7.9 Kg of magnesium sulfate. The drying agents were removed by filtration and the cake was washed with 4 gallons of ethyl acetate. The ethyl acetate layer was concentrated to 7 gallons under vacuum at an internal temperature of 24° C. The batch was then added to 11 gallons of IPO at 21° C. and allowed to granulate at 4° C. for 12 hours. The product was isolated via filtration and washed with 4 gallons of 5° C. IPO. The product was then dried at 34° C. for 22 hours with nitrogen bleed to recover 5.0 Kg of the title compound (66% yield).

Provenance & Evidence