Hydrochloric Acid → 3-Methyl-5-(2,2,2-trifluoroethoxy)-1,2-thiazole-4-sulfonyl chloride

Temperature

-5 °C

5 ml of acetic acid, 6 ml of 85% phosphoric acid, and 3 ml of concentrated hydrochloric acid was added to 2.1 g of 4-amino-3-methyl-5-(2,2,2-trifluoroethoxy)isothiazole prepared in the above step (2). 2 ml of aqueous solution containing 0.77 g of sodium nitrite was added dropwise to the above mixture at -20° to -10° C. The resulted solution was stirred at -5° C. for 30 minutes and was gradually added dropwise at -10° to -5° C. into 30 ml of an acetic acid solution, which had been saturated with sulfur dioxide and had contained 0.3 g of cuprous chloride. After the completion of dropping, the resulted solution was stirred and reacted at 0° to 5° C. for an hour. After the completion of the reaction, the reaction mixture was poured into ice-cold water, and was extracted with dichloromethane, and the extracted layer was sufficiently washed with water and dried. The solvent was subjected to distillation under reduced pressure to give 1.2 g of oily 3-methyl-5-(2,2,2-trifluoroethoxy)-4-isothiazolesulfonyl chloride.

1. customprepared in the above step (2)
2. additionwas added dropwise to the above mixture at -20° to -10° C
3. stirringthe resulted solution was stirred
4. customreacted at 0° to 5° C. for an hour
5. customAfter the completion of the reaction
6. additionthe reaction mixture was poured into ice-cold water
7. extractionwas extracted with dichloromethane
8. washthe extracted layer was sufficiently washed with water
9. customdried
10. distillationThe solvent was subjected to distillation under reduced pressure

ORD record

ord-56d68516e86e43fc9efcc6cb68504536

Source dataset

uspto-grants-1988_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04790869