Cesium carbonate → 3-(6-chloro-8-oxo-8,9-dihydro-7H-purin-2-ylamino)-4-nitrobenzonitrile

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Reaction Steps

To an oven-dried microwave flask under Ar was added 2-amino-6-chloro-7H-purin-8(9H)-one (0.64 g, 3.46 mmol, 1.0 equiv.) followed by anhydrous dioxane (10 mL) and anhydrous ethanol (4 mL); Cs2CO3 (Aldrich, 2.25 g, 6.92 mmol, 2 equiv.), 3-bromo-4-nitro-benzonitrile (1.02 g, 4.5 mmol, 1.3 equiv.), Xantphos (Strem, 0.6 g, 1.04 mmol, 0.3 equiv.) and Pd2(dba)3 (Strem, 0.32 g, 0.35 mmol, 0.1 equiv.) were all added as solids, and the mixture was stirred under Ar, at room temperature for 3 min. The flask was capped and heated in the microwave at 140° C. for 150 min (LC-MS shows reaction to be complete). The reaction mixture was cooled to room temperature, then concentrated in vacuo to give a dark brown residue, which was purified by flash chromatography (silica gel, gradual elution 3/1 ethyl acetate/hexanes, then 4/1 ethyl acetate/hexanes with 1% MeOH to 20% MeOH) to give the desired product as an orange solid in 46% yield. 1H NMR (300 MHz, CD3COOD) δ, ppm: 9.31 (d, 1H), 8.36 (d, 1H), 7.43 (dd, 1H); MS (EI) m/z 332.0 (MH)+.

Provenance & Evidence