Trifluoroacetic acid → (E)-2-(4,6-difluoro-1-indanylidene)acetic acid

HRID 1954867Notes

Reaction equation

HRID 1954867 reaction equation
FC(F)(F)C(O)=O.[F:8][C:9]1[CH:17]=[C:16]([F:18])[CH:15]=[C:14]2[C:10]=1[CH2:11][CH2:12][C:13]2([CH2:20][C:21]([OH:23])=[O:22])O>ClCCl>[F:8][C:9]1[CH:17]=[C:16]([F:18])[CH:15]=[C:14]2[C:10]=1[CH2:11][CH2:12]/[C:13]/2=[CH:20]\[C:21]([OH:23])=[O:22]

Participants

4

Reactant 2

HCID 6422Trifluoroacetic acidHCID 109112982-(4,6-Difluoro-1-hydroxy-1-indanyl)acetic acid

Product 1

HCID 10976722(E)-2-(4,6-difluoro-1-indanylidene)acetic acidYield 60.9%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

Trifluoroacetic acid (39.9 g, 0.35 mol) was added dropwise to a stirred, chilled (ice-methanol bath) mixture of 2-(4,6-difluoro-1-hydroxy-1-indanyl)acetic acid (11.3 g, 0.05 mol) in dichloromethane (250 mL). After 35 min. the mixture was concentrated in vacuo. Dichloromethane was added to the residue and the mixture was concentrated in vacuo. This procedure was repeated once more to give 6.4 g of crude (E)-2-(4,6-difluoro-1-indanylidene)acetic acid. Recrystallization of 0.9 g from acetone: water mixtures gave 0.15 g of (E)-2-(4,6-difluoro-1-indanylidene) acetic acid as a solid white: mp 238-239° C.; NMR (DMSO-d6): d 12.25 (br, 1H), 7.23-7.65 (m, 2H), 6.46 (t, 1H), 3.20-3.28, 2.97-3.20 (2m's, 4H); steady-state nOe: irradiation at 6.46 d, observed 21.6% nOe at 7.63 d.

Workup

  1. temperaturechilled
  2. concentrationAfter 35 min. the mixture was concentrated in vacuo
  3. additionDichloromethane was added to the residue
  4. concentrationthe mixture was concentrated in vacuo

Sources & evidence

ORD record
ord-a6e59663661743b380724392ccb99ece
Source dataset
uspto-grants-2000_09
Patent number
US06124284

Reaction notes

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