Dimethylformamide → ethyl 4,6-dichloro-3-formyl-1H-indole-2-carboxylate

Participants

Reaction Conditions

Reaction Steps

Combine 2-carboethoxy-4,6-dichloroindole (10.0 g, 0.039 mol), and dimethylformamide (4.5 mL, 0.057 mol) in dichloroethane (20 mL). Add phosphoryl chloride (8.9 g, 0.058 mmol). Heat to 80° C. After 18 hours, cool the reaction mixture to ambient temperature to give a solid. Filter the solid and combine with aqueous 1 M sodium acetate solution and stir. After 18 hours, filter, rinse with water, and dry to give the title compound: mp 216-217° C.; Rf =0.24 (silica gel, 1/1 ether/hexane); 1H NMR (CDCl3) δ 10.80 (s, 1 H), 9.40 (br s, 1 H), 7.39 (s, 1 H), 7.35 (s, 1 H), 4.52 (q, 2 H, J=7.2 Hz), 1.47 (t, 3 H, J=7.1 Hz).

Provenance & Evidence