Acetyl chloride → 1-(2,3-Dihydro-5-benzofuranyl)ethanone

Participants

Reaction Steps

AlCl3 (12.4 g, 93.0 mmol) was added in small portions to a stirred solution of AcCl (12.6 mL, 177.7 mmol) in dry DCM (100 mL) at −10° C. and the mixture stirred until homogeneous (15 min). The solution was added, via a cannula, to a stirred solution of 2,3-dihydro-1-benzofuran (190) (11.2 g, 93.0 mmol) in dry DCM (100 mL) at −10° C. and the solution stirred for 30 min at −10° C., and then poured into ice/cHCl (5:1 v/v, 1 L). The mixture was stirred for 2 h, extracted with DCM (3×100 mL), the combined organic fraction dried, and the solvent evaporated. The residue was purified by chromatography, eluting with a gradient (10-20%) of EtOAc/pet. ether, to give ketone 191 (14.23 g, 94%) as a white solid: mp 59-60° C. [lit. (Dun, J. P., et al., J. Med. Chem. 1986, 29, 2326-2329.) mp 60° C.]; 1H NMR δ 7.85 (d, J=1.9 Hz, 1H, H-4), 7.79 (dd, J=8.5, 1.9 Hz, 1H, H-6), 6.80 (d, J=8.5 Hz, 1H, H-7), 4.65 (t, J=8.7 Hz, 2H, H-2), 3.18 (br t, J=8.7 Hz, 2H, H-3), 2.13 (s, 3H, CH3).

Provenance & Evidence