To a solution of methyl 4-{(2R)-2-[((tert-butoxycarbonyl){(2R)-2-[6-(2,5-dimethyl-1H-pyrrol-1-yl)-3-pyridinyl]-2-hydroxyethyl}amino)methyl]-3,4-dihydro-2H-chromen-6-yl}benzoate (Example 375, 162 mg, 0.26 mmol) in ethanol (4 mL) was added hydroxylamine monohydrate (182 mg, 2.65 mmol) and 2 N aq. potassium hydroxide (0.66 mL, 1.32 mmol). The mixture was stirred at room temperature for 70 hours and then concentrated in vacuo. Flash chromatography of the residue using 10% methanol/ethyl acetate afforded 80 mg (43%) of the desired product containing trace impurities. This material was taken on without further purification. Mass spectroscopy gave m/z=534.3 [M+H]+ (calc'd exact mass for C30H35N3O6=533.3).
