Water → 5-Bromo-3-(trifluoromethyl)-4-isothiazolecarboxylic acid

Temperature

0 °C

Into a 100-mL round-bottom flask, was placed 5-bromo-3-(trifluoromethyl)-1,2-thiazole-4-carbonitrile (4.2 g, 16.34 mmol, 1.00 equiv), con. H2SO4 (10 mL). This was followed by the addition of a solution of NaNO2 (1.69 g, 24.49 mmol, 1.50 equiv) in water (5 mL) dropwise with stirring at 0° C. To this was added water (25 mL) dropwise with stirring at 0° C. The resulting solution was stirred for 2 days at 20° C. The resulting solution was allowed to react, with stirring, for an additional 5 h while the temperature was maintained at 50° C. in an oil bath. The reaction progress was monitored by LCMS. The resulting solution was extracted with 3×50 mL of ethyl acetate and the organic layers combined and dried over anhydrous sodium sulfate. The solids were filtered out. The resulting mixture was concentrated under vacuum. This resulted in 4.5 g of 5-bromo-3-(trifluoromethyl)-1,2-thiazole-4-carboxylic acid as yellow crude oil. Mass spectrum (ESI, m/z): Calcd. for C5HBrF3NO2S, 273.9 (M−H). found 273.9.

1. customInto a 100-mL round-bottom flask, was placed
2. stirringwith stirring at 0° C
3. stirringThe resulting solution was stirred for 2 days at 20° C
4. customto react
5. stirringwith stirring, for an additional 5 h while the temperature
6. temperaturewas maintained at 50° C. in an oil bath
7. extractionThe resulting solution was extracted with 3×50 mL of ethyl acetate
8. dry with materialdried over anhydrous sodium sulfate
9. filtrationThe solids were filtered out
10. concentrationThe resulting mixture was concentrated under vacuum
11. customThis resulted in 4.5 g of 5-bromo-3-(trifluoromethyl)-1,2-thiazole-4-carboxylic acid as yellow crude oil

ORD record

ord-1f1bf3f383374631a27e23bf5b0c8365

Source dataset

uspto-grants-2015_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09067898B1