(4-(4-chloro-1-methyl-5-(trifluoromethyl)-1H-pyrazol-3-yl)-5-fluoro-2-nitrophenoxy)acetic acid, ethyl ester → 6-(4-chloro-1-methyl-5-(trifluoromethyl)-1H-pyrazol-3-yl)-7-fluoro-2H-1,4-benzoxazin-3(4H)-one

Participants

Reaction Conditions

Reaction Steps

A solution of 4.5 g (0.0106 mole) (4-(4-chloro-1-methyl-5-(trifluoromethyl)-1H-pyrazol-3-yl)-5-fluoro-2-nitrophenoxy)-acetic acid, ethyl ester in 75 mL acetic acid was heated to 80° C. under a nitrogen atmosphere. The heat and nitrogen were removed and 1.8 g (0.033 mole) iron powder was added in 3 portions over 5 min. The solution was stirred at 80° C. for an additional 3 hours. The solution was cooled and filtered through Celite®. The filtrate was diluted with 100 mL water and extracted three times with ethyl acetate. The ethyl acetate extracts were washed with a saturated NaHCO3 solution, dried over anhydrous MgSO4, and concentrated in vacuo. The residue was recrystallized from methylcyclohexane/ethyl acetate to give 2.95 g (80%) of 6-(4-chloro-1-methyl-5-(trifluoromethyl)-1H-pyrazol-3-yl)-7-fluoro-2H-1,4-benzoxazin-3(4H)-one as a white solid, mp 207° C.

Provenance & Evidence