potassium carbonate in acetone 16 h; Heating / reflux;

1: tin (IV)-chloride; carbon disulfide 2: pyridine hydrochloride 3: aqueous acetic acid; bromine 4: ethanolic KOH-solution View Scheme

1: aqueous acetic acid; bromine 2: ethanolic KOH-solution View Scheme

1: pyridine hydrochloride 2: aqueous acetic acid; bromine 3: ethanolic KOH-solution View Scheme

1.1: potassium carbonate / acetone / 6 h / Reflux 2.1: hydrazine / water; diethylene glycol / 120 - 190 °C 2.2: 6 h / 120 - 130 °C 3.1: carbon disulfide / 0.5 h / Inert atmosphere; Cooling with ice 3.2: 6 h / 20 °C / Cooling with ice 4.1: ethyl mercaptan sodium salt / N,N-dimethyl-formamide / 1 h / 125 - 130 °C 5.1: bromine; acetic acid / 0.25 h 6.1: potassium carbonate / tetrahydrofuran / 0.17 h 6.2: 16 h / 40 °C View Scheme

1.1: hydrazine / water; diethylene glycol / 120 - 190 °C 1.2: 6 h / 120 - 130 °C 2.1: carbon disulfide / 0.5 h / Inert atmosphere; Cooling with ice 2.2: 6 h / 20 °C / Cooling with ice 3.1: ethyl mercaptan sodium salt / N,N-dimethyl-formamide / 1 h / 125 - 130 °C 4.1: bromine; acetic acid / 0.25 h 5.1: potassium carbonate / tetrahydrofuran / 0.17 h 5.2: 16 h / 40 °C View Scheme

1: tin (IV)-chloride; carbon disulfide 2: pyridine hydrochloride 3: aqueous acetic acid; bromine 4: ethanolic KOH-solution View Scheme