Cesium carbonate → cis-3,5-Dimethyl-1-[2-(methyloxy)-5-nitrophenyl]piperazine

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Reaction Steps

Cesium carbonate (9.77 g, 30 mmol), palladium (II) acetate (448 mg, 2 mmol) and rac-2,2′-bis(diphenylphosphino)-1,1′-binapthyl (1.87 g, 3 mmol) were stirred under an inert atmosphere in tetrahydrofuran (40 ml) for 30 minutes. 2-Bromo-4-nitroanisole (4.64 g, 20 mmol) and cis-2,6-dimethylpiperazine (6.85 g, 60 mmol) in tetrahydrofuran (20 ml) was added and the mixture heated at reflux for 24 hours. After cooling to room temperature the reaction mixture was diluted with ethyl acetate and extracted with 2N hydrochloric acid (×3). The aqueous extract was stirred with ethyl acetate and activated charcoal, filtered through celite. The aqueous component of the filtrate was separated and the pH of the solution was adjusted to pH 7 with 50% potassium hydroxide solution and the solution evaporated in vacuo to a small volume. The residue was basified to pH 10 with 50% potassium hydroxide solution and extracted with dichloromethane (×3). The combined organic extracts were washed with saturated brine, dried over anhydrous sodium sulfate and concentrated in vacuo to afford the title product (D1). MS (ES+) m/e 266 [M+H]+.

Provenance & Evidence