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

HRID 362820Notes

Reaction equation

HRID 362820 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 white solid: mp 238°-239° C.; NMR (DMSO-d6): d12.25 (br, 1H), 7.23-7.65 (m, 2H), 6.46 (t, 1H), 3.20-3.28, 2.97-3.20(2 m'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-a1c130c3073d4ec1a9aaa92096667493
Source dataset
uspto-grants-1999_02
Patent number
US05872118

Reaction notes

Loading…