Phosphonic acid, P-(chloromethyl)-, diethyl ester → Diethyl[(6-methoxy-5-nitropyridin-2-yl)methyl]phosphonate

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Reaction Steps

A solution of 2-methoxy-3-nitropyridine (6.92 g, 44.9 mmol) and diethyl chloromethylphosphonate (7.00 mL, 44.9 mmol) in 40 mL DMSO was added drop wise to a stirred mixture of potassium tert-butoxide (15.1 g, 134.6 mmol) and 40 mL DMSO. The mixture was stirred at room temperature for 30 minutes, after which, it was poured into a 1N HCl/ice mixture and extracted with methylene chloride. The combined organic layers were washed with water, brine, dried over anhydrous sodium sulfate, filtered, concentrated and purified by column chromatography (DCM:EtOAc1:1). The slower eluting regioisomer was collected and confirmed to be the desired product (750 mg, 5.5% yield). MS (ES+): m/z 305.16 (100) [MH+]; HPLC: tR=1.16 min (UPLC, Analytical).

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