反应详情

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).

1. temperaturethe reaction mixture chilled to 10 C
2. customwas started into the reaction
3. temperaturewas maintained throughout
4. customthe pH of the reaction to 2.0 wherein a precipitate
5. customwas formed
6. filtrationThe precipitate was collected by filtration
7. washwashed with water
8. customdried