Sulfuric Acid → 5-(3-Fluoropyridin-4-yl)-6-pyridin-3-ylpyrazin-2(1H)-one

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Reaction Steps

A solution of sodium nitrite (0.248 g, 3.6 mmol) in water (2.5 mL) was added dropwise to a stirred, cooled (ice-bath) mixture of 5-(3-fluoropyridin-4-yl)-6-pyridin-3-ylpyrazin-2-amine (Example 115) (0.80 g, 3.0 mmol) and 5% aqueous sulphuric acid (18 mL). After 1 hour, the mixture was taken to pH 5-6 with aqueous sodium hydroxide solution with external cooling. The mixture was concentrated to low bulk then extracted with chloroform. The organic layer was dried (MgSO4) and concentrated in vaccuo to give the title compound (0.793 g, 99%) as a white solid.

Provenance & Evidence