Carbon Dioxide → 2,4,5-Trifluoro-3-(trifluoromethyl)benzoic acid

HRID 2073836Notes

Reaction equation

C([Li])CCC.Br[C:7]1[CH:12]=[C:11]([F:13])[C:10]([F:14])=[C:9]([C:15]([F:18])([F:17])[F:16])[C:8]=1[F:19].[C:20](=[O:22])=[O:21].C(O)(C(F)(F)F)=O>CCOCC>[F:19][C:8]1[C:9]([C:15]([F:18])([F:17])[F:16])=[C:10]([F:14])[C:11]([F:13])=[CH:12][C:7]=1[C:20]([OH:22])=[O:21]

Participants

Conditions

Temperature: -78 °C

Procedure

A solution of n-butyl lithium (2.6M in hexanes, 9.6 ml, 25 mmol) was added dropwise through an addition funnel over 15 minutes to a solution of 1-bromo-2,4,5-trifluoro-3-(trifluoromethyl)benzene (7.00 g, 25 mmol) in ether (100 ml) stirred under N2 at -78° C. After 5 minutes the mixture was rapidly blown by catheter onto a suspension of dry ice (100 g) in ether (100 ml). After 5 minutes TFA (2 ml) was added to this. When the solution had warmed up to 20° C., it was washed with diluted HCl (0.5M, 20 ml), and extracted with dilute base (0.5N, 2×50 ml). The combined basic extracts were washed with ether (25 ml), made acidic with concentrated HCl (~4 ml), and extracted with ether (3×50 ml). The combined ethereal extracts were washed with water (50 ml), saturated brine (50 ml), and dried (MgSO 4). The solvent was removed under reduced pressure to give 2,4,5-trifluoro-3-(trifluoromethyl)benzoic acid (4.21 g, 69%) as white microscopic needles; mp 87°-90° C. Nmr (CDC3) δ 11.80 (1H, br s, OH), 8.05 (1H, d of t, Jd =6 Hz, aromatic).

Workup

temperatureWhen the solution had warmed up to 20° C.
washit was washed with diluted HCl (0.5M, 20 ml)
extractionextracted
additionwith dilute base (0.5N, 2×50 ml)
washThe combined basic extracts were washed with ether (25 ml)
extractionextracted with ether (3×50 ml)
washThe combined ethereal extracts were washed with water (50 ml), saturated brine (50 ml)
dry with materialdried (MgSO 4)
customThe solvent was removed under reduced pressure

Sources & evidence

ORD record: ord-257aa5f57f3f4eadb456fa9478b49f60
Source dataset: uspto-grants-1990_04
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US04920120

Reaction notes

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