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

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Reaction Steps

To an oven-dried 2-neck flask under Ar was added racemic BINAP (2.59 g, 4.17 mmol, 0.35 equiv.) followed by anhydrous toluene (20 mL) and Pd(OAc)2 (1.20 g, 1.79 mmol, 0.15 equiv.) and the mixture was stirred under Ar, at room temperature for 15 min. A deep yellow paste is formed. Then, 3-bromo-4-nitro-benzonitrile (3.51 g, 15.47 mmol, 1.3 equiv.), 2-amino-6-chloro-9-(tetrahydro-2H-pyran-4-yl)-7H-purin-8(9H)-one (3.2 g, 11.9 mmol, 1.0 equiv.) and cesium carbonate (5.81 g, 17.8 mmol, 1.5 equiv.) were added as solids, under Ar, followed by anhydrous toluene (27 mL), and the reaction mixture was stirred at room temperature for 10 min, then stirred at 100° C. for 22 h (LC-MS shows reaction to be complete). The reaction mixture was cooled to room temperature, diluted with toluene (450 mL) and passed through Celite. The filtrate was concentrated in vacuo to give a dark brown residue. The desired product was recrystallized as a bright orange solid from the residue using mixtures of 100 mL acetonitrile/100 mL water. Repeated recrystallizations resulted in isolation of 1.49 g of desired product (30% yield) in high purity. 1H NMR (300 MHz, CDCl3) δ, ppm: 10.40 (s, 1H), 9.33 (s, 1H), 8.35 (d, 1H), 7.85 (br s, 1H), 7.31 (d, 1H), 4.65-4.50 (m, 1H), 4.19 (dd, 2H), 3.55 (app t, 2H), 2.70 (tdd, 2H), 1.90 (br d, 2H); MS (EI) m/z 416.2 (MH)+.

Provenance & Evidence