Indole → 1H-Indole-1-propionic acid

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Reaction Steps

KOH (11.5 g, 0.2 mol.) was added to a solution of indole (5.0 g, 40.0 mmol.) and 3-bromopropionic acid methyl ester (4.37 ml, 40 mmol.) in DMSO (35 ml), and stirring was carried out for 24 h at RT. For working up, water (50 ml) was added to the mixture, washing was carried out with ether (5×20 ml), and the aqueous phase was adjusted to pH 4 with 1M HCl and extracted with ether (5×20 ml). The combined extracts were dried, filtered and concentrated. Chromatography with methanol yielded 3-indol-1-ylpropionic acid in a yield of 3.8 g (white solid, m.p. 54–56° C.).

Provenance & Evidence