1,1'-Carbonyldiimidazole → 1-[(2S,3S)-2-[(tert-Butoxycarbonyl)amino]-3-[3-[2-chloro-4-[(methylsulfonyl)amino]phenyl]-1,2,4-oxadiazol-5-yl]-1-oxobutyl]pyrrolidine

Beteiligte Stoffe

Reaktionsschritte

To a stirred solution of the product from Step B (132.0 mg, 0.44 mmol) in dichloromethane (5 mL) was added 1,1′-carbonyldiimidazole (148.0 mg, 0.91 mmol). After stirring at room temperature for 1 h, 2-chloro-N′-hydroxy-4-[(methylsulfonyl)amino]benzenecarboximidamide (Intermediate 6, 145.0 mg, 0.55 mmol) was added. After stirring at room temperature for 2 h, the reaction was quenched with saturated aqueous ammonium chloride solution. The organic phase was then dried over anhydrous sodium sulfate and concentrated in vacuo. The residue was dissolved in 10 mL of toluene and heated at 110° C. for 12 h. The toluene was removed under reduced pressure and the residue was then purified by preparative thin layer chromatography (silica gel, 30:70 hexanes/ethyl acetate) to give the desired product.

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