Borane;tetrahydrofuran → N-(3-Propylamino-3,4-dihydro-2H-pyrano[3,2-b]pyridin-7-yl)-4-trifluoromethoxybenzenesulfonamide

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Reaction Steps

To a solution of N-[7-(4-trifluoromethoxy-benzenesulfonylamino)-3,4-dihydro-2H-pyrano[3,2-b]pyridin-3-yl]-propionamide (93 mg, 0.20 mmol) in THF (20 ml) was added dropwise 1M BH3.THF (2.08 ml, 2.08 mmol) and the mixture was stirred at room temperature for 12 h. It was then quenched by adding carefully 1N aqueous HCl (8 ml) and then the resulting solution was heated at reflux for 4 h. The solution was cooled to room temperature, the aqueous mixture was adjusted to pH˜8 with 2 N NaOH solution and diluted with CH2Cl2. Separation of the layers, drying (Na2SO4) of the organic phase and evaporation in vacuo provided the crude material, which was purified by flash column chromatography (CH2Cl2:methanol, 97:3) to give the title compound (70 mg, 78%) as a white amorphous solid.

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