6-Methoxy-3-(trichloromethyl)-2-benzofuran-1(3H)-one → Benzoic acid, 2-(2,2-dichloroethenyl)-5-methoxy-

Participants

Reaction Steps

A 100 mL round-bottomed flask containing a stirring bar was charged with 6-methoxy-3-(trichloromethyl)isobenzofuran-1(3H)-one (3.09 g, 10.94 mmol) and glacial acetic acid (40.0 mL). Zinc dust (2.86 g, 43.76 mmol) was added in small portions over 30 min. to the stirred reaction mixture. The reaction was left stirring at room temperature for further 30 min. and then heated at reflux for 1 h. It was filtered hot over a pad of Celite and the filtrates were diluted with water. The precipitate formed was collected by filtration and recrystallised from EtOH/H2O to give 2-(2,2-dichlorovinyl)-5-methoxybenzoic acid as white needles (1.74 g, 64%). Spectral data for this compound were consistent with those in the literature. M.p. 164-166° C. (lit. m.p. 167-168° C.); 1H NMR (400 MHz, DMSO-d6): δ=13.31 (br. s, 1H), 7.51 (d, J=8.7 Hz, 1H), 7.47-7.39 (m, 2H), 7.21 (dd, J=8.7 Hz, J=2.2 Hz, 1H), 3.82 (s, 3H).

Provenance & Evidence