Potassium Iodide → 2-{[(4-tert-Butoxycarbonylamino-butyl)-(3,4-dihydro-2H-pyrano[3,2-b]pyridin-4-yl)-amino]-methyl}-benzimidazole-1-carboxylic acid tert-butyl ester

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Reaction Steps

To a solution of [4-(3,4-Dihydro-2H-pyrano[3,2-b]pyridin-4-ylamino)-butyl]-carbamic acid tert-butyl ester (329 mg, 1.02 mmol) in CH3CN (5 mL) was added N,N-diisopropylethylamine (0.28 mL, 1.63 mmol) followed by 2-chloromethyl-benzimidazole-1-carboxylic acid tert-butyl ester (328 mg, 1.23 mmol) and potassium iodide (20 mg, 0.1 mmol). The resultant mixture was heated to 60° C. for 16 hours then cooled to room temperature. The mixture was concentrated and the residue was partitioned between CH2Cl2 (25 mL) and saturated aqueous NaHCO3 (20 mL). The phases were separated and the aqueous phase was extracted with CH2Cl2 (2×15 mL). The combined organic extracts were dried (Na2SO4), filtered, and concentrated. Purification of the crude material by flash column chromatography on silica gel (CH2Cl2/MeOH/NH4OH, 95:4:1) provided 2-{[(4-tert-Butoxycarbonylamino-butyl)-(3,4-dihydro-2H-pyrano[3,2-b]pyridin-4-yl)-amino]-methyl}-benzimidazole-1-carboxylic acid tert-butyl ester (380 mg, 67%) as a white foam.

Provenance & Evidence