Ammonium Chloride → 1-(6-methoxy-3,4-dihydro-2H-1-oxa-9-aza-phenanthren-3-yl)-1H-pyrazol-4-ylamine

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Reaction Steps

Ammonium chloride (4.0 g, 73.54 mmol, 6.0 eq) is added at room temperature to a stirred suspension of 6-methoxy-3-(4-nitro-pyrazol-1-yl)-3,4-dihydro-2H-1-oxa-9-aza-phenanthrene (4.0 g, 12.26 mmol, 1.0 eq) and iron powder (8.22 g, 147.10 mmol, 12.0 eq) in ethanol (600 mL). The resulting mixture is heated under reflux for 2 hours, then filtered through decalite, solvent is removed and the crude is extracted with ethyl acetate (3×200 mL) and water (200 mL). The combined organic layers are dried over sodium sulfate, filtered and concentrated to give a residue that is purified by column chromatography (silica gel, eluent: petroleum ether:ethyl acetate:methanol, 1:1:0 to 0:25:1, v/v/v) to afford 1-(6-methoxy-3,4-dihydro-2H-1-oxa-9-aza-phenanthren-3-yl)-1H-pyrazol-4-ylamine as a white solid (800 mg, 22% yield).

Provenance & Evidence