1-Bromo-3-chloropropane → 5-Chloro-1-(3-chloropropyl)indole-3-carboxaldehyde

Participants

Reaction Steps

To a stirred mixture of powdered potassium hydroxide (85%, 2.6 g, 39 mmol) in methyl sulfoxide (20 mL) was added dropwise a solution of 5-chloroindole-3-carboxaldehyde (3.5 g, 19 mmol) in methyl sulfoxide (5 mL). The mixture was stirred for 30 min and 1-bromo-3-chloropropane (2.9 mL, 29 mmol) was added dropwise. The mixture was stirred for 1 h and partitioned between ethyl acetate (3×40 mL) and water (100 mL). The combined organic extracts were washed (water, brine), dried (sodiurn sulfate) and concentrated in vacuo. The solid residue was recrystallised (2-propanol) to give the product as a white solid (4.1 g, 82%): mp 107-108° C.; Found: C, 56.51; H, 4.26; N, 5.44%. C12H11Cl2NO requires: C, 56.27; H, 4.33; N, 5.47%.

Provenance & Evidence