Trifluoroacetic acid → (E)-2-(6-fluoro-1-indanylidene)acetic acid

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Reaction Steps

Trifluoroacetic acid (100 mL) was added to a stirred, chilled (ice-methanol bath) solution of 2-(6-Fluoro-1-hydroxy-1-indanyl)acetic acid (37.5 g, 0.18 mol) in dichloromethane (900 mL). After 15 min, the mixture was concentrated in vacuo to give (E)-2-(6-fluoro-1-indanylidene)acetic acid as a yellowish-tan solid (33.0 g, 95%), m.p., 203°-205° C.; NMR (DMSO-d6): d 12.05 (br s, 1H, COOH), 7.16-7.65 (m, 3H, Ar), 6.37 (t,1H, =CH), 2.94-2.98, 3.15-3.20 (2m's, 4H, 2XCH2); steady-state nOe:irradiation at 6.37 d, observed 24% nOe at 7.65 d.

Provenance & Evidence