potassium hydroxide; iodine in water; N,N-dimethyl-formamide 0.5 h; Ambient temperature;

1: sulfuric acid / 24 h / Inert atmosphere; Reflux 2: N-chloro-succinimide; sodium iodide / N,N-dimethyl-formamide / 0 - 20 °C / Inert atmosphere View Scheme

potassium carbonate; tetrakis(triphenylphosphine) palladium(0) in ethanol; water; toluene 48 h; Heating / reflux;

1: ethyl 3-iodo-1H-indole-2-carboxylate With sodium hydride in tetrahydrofuran; mineral oil T=0°C; 0.75 h; Inert atmosphere; 2: benzenesulfonyl chloride in tetrahydrofuran; mineral oil T=0 - 20°C; 16 h; Inert atmosphere;