Cesium carbonate → tert-butyl 4-{3-[(3R)-3-({(1S)-3-methoxy-1-[5-(2-{[(4-methylphenyl)sulfonyl]oxy}ethoxy)pyridin-3-yl]-3-oxopropyl}carbamoyl)piperidin-1-yl]-3-oxopropyl}piperidine-1-carboxylat

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Reaction Steps

Tert-butyl 4-{3-[(3R)-3-({(1S)-1-[5-(benzyloxy)pyridin-3-yl]-3-methoxy-3-oxopropyl}carbamoyl)piperidin-1-yl]-3-oxopropyl}piperidine-1-carboxylate (example 5e, 200 mg, 0.37 mmol) was dissolved in N,N-dimethylformamide (25.3 mL). Cesium carbonate (298 mg, 0.92 mmol) and ethylene glycol bis-p-toluenesulfonate (203 mg, 0.55 mmol) were added. The mixture was stirred at room temperature for 2 hours and stored at 5° C. for 17 hours. The mixture was quenched by addition of saturated aqueous ammonium chloride solution and extracted with ethyl acetate. The combined extracts were washed with brine and dried over sodium sulfate. The solution was concentrated under reduced pressure and the residue was purified by preparative thin layer chromatography on silica gel (ethyl acetate 100%) to yield 109 mg of tert-butyl 4-{3-[(3R)-3-({(1S)-3-methoxy-1-[5-(2-{[(4-methylphenyl)sulfonyl]oxy}ethoxy)pyridin-3-yl]-3-oxopropyl}carbamoyl)piperidin-1-yl]-3-oxopropyl}piperidine-1-carboxylat.

Provenance & Evidence