Citric Acid → (2S,4R)-1-(tert-butoxycarbonyl)-4-(6-methoxy-3-methylisoquinolin-1-yloxy)pyrrolidine-2-carboxylic acid

Beteiligte Stoffe

Reaktionsschritte

N-BOC-4-hydroxy-L-proline (A; 281 mg; 1.21 mmol) was dissolved in dimethylsulfoxide (3 mL) at room temperature then potassium t-butoxide (270 mg; 2.4 mmol) was added. The resulting solution was stirred at room temperature for 2 hours, then cooled to 0° C. A solution of 1-chloro-6-methoxy-3-methylisoquinoline in dimethylsulfoxide (3 mL) was then added dropwise to the cold solution, followed by t-BuOK, and the mixture was allowed to warn to room temperature. The solution was stirred for 16 hours. The reaction mixture was acidified to pH=4 with 5% aq. citric acid. The solution was extracted with ethyl acetate and the organic phase washed with water followed by brine. The organic phase was concentrated under reduced pressure to give (2S,4R)-1-(tert-butoxycarbonyl)-4-(6-methoxy-3-methylisoquinolin-1-yloxy)pyrrolidine-2-carboxylic acid.

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