4,6-Dichloro-5-nitropyrimidine → 5-Amino-4,6-dichloropyrimidine

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Reaction Steps

A mixture of 4,6-dichloro-5-nitroprimidine (E-1) (20.0 g, 104 mmmol) and stannous chloride dihydrate (117.7 g, 520 mmol) in EtOH (300 mL) is stirred at reflux for 2 h. The resulting mixture is allowed to cool to RT and then concentrated in vacuo. The residue is poured into ice water (300 mL) and neutralized with saturated NaHCO3 aqueous solution to adjust the pH value to 5-6. The resulting mixture is stirred at RT for 30 min and then extracted with ethyl acetate (3×200 mL). The combined organic layers are washed with brine, dried over Na2SO4 and filtered. The filtrate is concentrated in vacuo to afford the product, 4,6-dichloropyrimidine-5-amine (E-2).

Provenance & Evidence