Sodium hydride → ethyl 5-((tert-butyldiphenylsilyloxy)methyl)-6-((2R,6S)-2,6-dimethylmorpholino)-7-fluorobenzo[d]isoxazole-3-carboxylate

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Reaction Steps

Sodium hydride (0.159 g, 3.97 mmol) was suspended in 20 ml of DMF and cooled in an ice bath. Ethyl 2-(5-((tert-butyldiphenylsilyloxy)methyl)-4-((2R,6S)-2,6-dimethylmorpholino)-2,3-difluorophenyl)-2-(hydroxyimino)acetate (Intermediate 165, 1.94 g, 3.18 mmol) was dissolved in 20 ml of DMF and added to the reaction flask. The ice bath was removed and the reaction stirred at room temperature for 2 hours. The reaction was quenched with sat NH4Cl (5 ml), diluted with water and extracted three times with ethyl acetate. The organic layers were combined, washed with water and brine 5×, dried over MgSO4 and concentrated. The residue was purified by silica gel column chromatography using a gradient of hexanes to ethyl acetate to give the title compound (1.250 g, 66.6%).

Provenance & Evidence