1-Bromo-2-[(2,2-dimethoxyethyl)sulfanyl]benzene → 7-Bromobenzo[b]thiophene

Participants

Reaction Steps

To a 500 ml 3-neck flask was weighed out 15 g of polyphosphoric acid (PPA) followed by chlorobenzene (250 ml). After the mixture was heated to reflux (2-bromo-phenylsulfanyl)-acetaldehyde dimethylacetal (8.0 g in 60 ml chlorobenzene, 28.9 mmol) was added dropwise over 2.5 h via addition funnel and refluxed for an additional 24 h. After the reaction cooled it was filtered through a silica plug and concentrated to 6.04 g amber colored oil. Further purification by column chromatography (100% hexanes) afforded 5.47 g (89%) product as a clear oil: 1H NMR (300 MHz, DMSO-d6): δ 7.37 (1H, t, J=7.8 Hz), 7.63 (2H, m), 7.90 (1H, d, J=5.5 Hz), 7.94 (1H, d, J=7.9 Hz).

Provenance & Evidence