Trifluoroacetic acid → (2E)-3-{4-[Cyclohexylidene(4-hydroxyphenyl)methyl]-2-methylphenyl}-2-propenoic acid

Participants

Reaction Steps

Trifluoroacetic acid (2.0 mL) was added dropwise to 68 (210 mg, 0.519 mmol) dissolved in CH2Cl2 (2 mL) at 0° C. The reaction mixture was stirred at RT for 3 h and the volatiles were removed under reduced pressure. The residue was chromatographed on silica gel (20:1 CH2Cl2:MeOH) and recrystallized (EtOAc:hexanes) to afford 138 mg (76%) of 69 as a pale yellow solid. 1H NMR (400 MHz, DMSO-d6): δ 1.51 (br s, 6H), 2.13 (m, 4H), 2.30 (s, 3H), 6.35 (d, J=16.0 Hz, 1H), 6.66 (d, J=8.2 Hz, 2H), 6.82-6.91 (m, 4H), 7.59 (d, J=7.9 Hz, 1H), 7.75 (d, J=16.0 Hz, 1H), 9.31 (s, 1H), 12.36 (br s, 1H). LRMS (ESI): m/z 349 (M+H)+.

Provenance & Evidence