p-Toluenesulfonic acid → HCID 66998464, compound

Participants

Reaction Steps

A mixture of 7-fluoro-2-hydroxy-2,3-dihydro-benzofuran-4-carboxylic acid ethyl ester and 7-fluoro-2-methoxy-2,3-dihydro-benzofuran-4-carboxylic acid ethyl ester (1.15 g, see above) in toluene (6.0 mL) is added dropwise to a solution of PTSA (0.25 mmol) in toluene (5.0 mL) which is heated to reflux. Heating is continued for 5 h, an additional portion of PTSA (0.25 mmol) is added and the mixture is again heated to reflux for 7 h. The solvents are removed in vacuo and the residue is purified by flash chromatography (gradient: heptane to heptane/EtOAc 95/5) to give the desired product. 1H-NMR (CDCl3): δ=7.99 (dd, J=8.3 Hz, J=4.3 Hz, 1H); 7.78 (s, 1H); 7.44 (bs, 1H); 7.10 (t, J=9.3 Hz, 1H); 4.46 (q, J=7.0 Hz, 2H); 1.47 (t, J=7.0 Hz, 3H).

Provenance & Evidence