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

HRID 868510Notes

Reaction equation

HRID 868510 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

6

Reactant 4

HCID 280Carbon DioxideHCID 6422Trifluoroacetic acidHCID 142788261-Bromo-2,4,5-trifluoro-3-(trifluoromethyl)benzeneHCID 178418339Butyllithium

Product 1

HCID 142788272,4,5-Trifluoro-3-(trifluoromethyl)benzoic acidYield 69%

Reagents, catalysts & solvents 1

HCID 3283Diethyl EtherSolvent2×

Conditions

Temperature
20 °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°. After 5 minutes the rxn 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 (CDCl3) δ 11.80 (1H, br s, OH), 8.05 (1H, d of t, Jd =6 Hz, Jt =9 Hz, aromatic). IR (KBr) 1721, 1636, 1511, 1464, 1424, 1328, 1256, 1154, 928 cm-1. M⊕ 244 (56).

Workup

  1. washit was washed with diluted HCl (0.5M, 20 mL)
  2. extractionextracted
  3. additionwith dilute base (0.5N, 2×50 mL)
  4. washThe combined basic extracts were washed with ether (25 mL)
  5. extractionextracted with ether (3×50 mL)
  6. washThe combined ethereal extracts were washed with water (50 mL), saturated brine (50 mL)
  7. dry with materialdried (MgSO 4)
  8. customThe solvent was removed under reduced pressure

Sources & evidence

ORD record
ord-397b47ceeea14ad9b18995968a66682d
Source dataset
uspto-grants-1988_10
Patent number
US04780468

Reaction notes

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