Sodium Sulfate → ethyl 5-(benzyloxy)-4-fluoro-2-(tetrahydro-2H-pyran-4-ylamino)benzoate

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Reaction Steps

A mixture of 10.5 g of the compound obtained in Step 4.2, 29.07 g of tetrahydro-4H-pyran-4-one and 51.56 g of Na2SO4 in 360 ml of acetic acid is stirred overnight at room temperature. 34.62 g of sodium triacetoxyborohydride are then added and the mixture is stirred for 3 hours at room temperature. The resulting mixture is evaporated under reduced pressure and the residue is taken up in EtOAc. This solution is washed with water and then 4 times with saturated aqueous NaHCO3 solution. The resulting solution is dried over MgSO4 and filtered, and the filtrate is evaporated under reduced pressure. The residue is chromatographed on silica gel, eluting with a PE/EtOAc mixture from (100/0, v/v) to (50/50, v/v) to give 10.55 g of the expected product.

Provenance & Evidence