Reacción #87908

Ecuación de reacción

xylene

1-(5-amino-2,4-dichlorophenyl)-4,5-dihydro-4-difluoromethyl-3-methyl-1,2,4-triazol-5(1H)-one

methanesulfonyl chloride

sodium carbonate

potassium carbonate

hydrochloric acid

water

→

N-[2,4-dichloro-5-[4-(difluoromethyl)-4,5-dihydro-3-methyl-5-oxo-1H-1,2,4-triazol-1-yl] phenyl]methanesulfonamide

Condiciones de reacción

Tratamiento posterior

1. 1
   Temperaturathe reaction mixture chilled to 10 C
2. 2
   Otrowas started into the reaction
3. 3
   Temperaturawas maintained throughout
4. 4
   Otrothe pH of the reaction to 2.0 wherein a precipitate
5. 5
   Otrowas formed
6. 6
   FiltraciónThe precipitate was collected by filtration
7. 7
   Lavadowashed with water
8. 8
   Otrodried

Procedimiento

The solid 1-(5-amino-2,4-dichlorophenyl)-4,5-dihydro-4-difluoromethyl-3-methyl-1,2,4-triazol-5(1H)-one (1.0 equiv.) was suspended in 20 equivalent of water and the reaction mixture chilled to 10 C. Vigorous stirring was commenced and 0.05 equiv of tetra-n-propylammonium chloride in 0.05 equiv of xylene was added. Using a pH meter, the of the suspension was brought to 7.8 by adding adequate quantity of 1 molar sodium carbonate aqueous solution. Simultaneous addition of 1.2 equiv methanesulfonyl chloride was started into the reaction while keeping the flow of the aqueous potassium carbonate on such that the of 7.8 was maintained throughout. After 45 minutes the reaction was complete and the suspension was replaced by a clear solution. Concentrated hydrochloric acid was added slowly to bring the pH of the reaction to 2.0 wherein a precipitate was formed. The precipitate was collected by filtration, washed with water and dried to give the N-[2,4-dichloro-5-[4-(difluoromethyl)-4,5-dihydro-3-methyl-5-oxo-1H-1,2,4-triazol-1-yl] phenyl]methanesulfonamide as a white solid (0.95 equiv and 97% purity).

Fuente