tert-Butyl (2R)-2-methylpiperazine-1-carboxylate → (3R)-1-(4-ethoxy-3-methoxyphenyl)-3-methylpiperazine

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

Palladium(II) acetate (0.049 g, 0.22 mmol)and (R)-(+)-2,2'-Bis(diphenylphosphino)-1,1'-binaphthyl (0.108 g, 0.17 mmol) were added to 4-bromo-1-ethoxy-2-methoxybenzene (1 g, 4.33 mmol),(R)-1-N-Boc-2-methyl piperazine (0.867 g, 4.33 mmol) and Sodium tert- butoxide (0.624 g, 6.49 mmol) in anhydrous Toluene (20 mL) under argon. The resulting solution was stirred at reflux for18 hours. The reaction was allowed to cool to room temperature and diluted with dcm (50 ml). This was washed with water (2 x 50 ml), dried over sodium sulfate, filtered and the solvent removed under reduced pressure. The crude product was dissolved in hydrochloric acid solution in methanol (4N, 20 ml) and stirred at room temprature overnight. The solvent was removed under reduced pressure.The crude product was purified by ion exchange chromatography, using an SCX column. The desired product was eluted from the column using 7M NH3/MeOH and pure fractions were evaporated to dryness to afford (R)-1-(4-ethoxy-3-methoxyphenyl)-3-methylpiperazine (0.550 g, 50.8 %) as a yellow gum.

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