(o-Carboxyphenylthio)acetic acid → 3-Chloro-1-benzothiophene-2-carbaldehyde

Beteiligte Stoffe

Reaktionsschritte

Vilsmeier reagent was prepared via the dropwise addition of POCl3 (7.9 mL, 84 mmol) into ice-cold DMF (14 mL). A solution of 2-carboxymethylsulfanyl-benzoic acid (3.0 g, 14 mmol) in DMF (15 mL) was added dropwise to the Vilsmeier reagent. The resulting mixture was warmed to room temperature and then heated to 80° C. for 3.5 h. The reaction mixture was cooled to ambient temperature. Crushed ice was added until a bright yellow precipitate appeared. The solid was isolated by filtration. Purification by flash column chromatography (silica gel, hexanes/ethyl acetate 3:2) gave the title compound (1.87 g, 68%) as a yellow powder: 1H NMR (300 MHz, CDCl3) δ 10.36 (s, 1H), 8.03 (m, 1H), 7.86 (m, 1H), 7.59-7.53 (m, 2H).

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