Hydrochloric Acid → tert-butyl 4-[[[phenyl(1H-pyrrolo[2,3-c]pyridin-2-yl)methylene]amino]oxy]piperidine-1-carboxylate

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Reaction Steps

A mixture of phenyl(1H-pyrrolo[2,3-c]pyridin-2-yl)methanone (Example 35) (300 mg, 1.34 mmol) and tert-butyl 4-(aminooxy)piperidine-1-carboxylate (Reference Example 10) (289 mg, 1.34 mmol) in EtOH (30 mL) was adjusted to pH 4-5 with HCl (1.9 mL of a 1 N HCl solution in diethyl ether, 1.9 mmol). The reaction mixture was heated to reflux. After 3 h, the reaction mixture was concentrated under reduced pressure. The residue was partitioned between EtOAc and saturated NaHCO3. The aqueous layer was separated and extracted with EtOAc. The combined organic layers were dried (Na2SO4) and concentrated under reduced pressure. Purification by column chromatography (silica gel, 98:2 CH2Cl2/MeOH to 95:5 CH2Cl2/MeOH) gave tert-butyl 4-[[[phenyl(1H-pyrrolo[2,3-c]pyridin-2-yl)methylene]amino]oxy]piperidine-1-carboxylate (120 mg, 23%) as a white amorphous solid (geometry of the oxime double bond undefined).

Provenance & Evidence