Compound 23

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Synthetic procedure: See article for the definitive version of this procedure and for full experimental details.

Trans-2-phenylvinylboronic acid (0.5 g, 1 eq, 3.6 mmol) was dissolved in 20 mL THF. The catalyst, PdCl₂(PPh₃)₂ (76 mg, 0.03 eq, 0.11 mmol) was added followed by potassium phosphate tribasic (1.5 g, 2 eq, 7.2 mmol). The 2,4-dichloropyrimidine (0.5 g, 1 eq, 3.6 mmol) was dissolved in 4 mL THF and then added to the stirred solution via syringe. Water (3 mL) was added. The flask was equipped with a condenser and brought to a reflux for 24 hours. The reaction was quenched with 20 mL water. The organic products were extracted with 3x25 mL Et₂O. They were combined and washed with brine (30 mL), dried over MgSO₄ and concentrated under reduced pressure. The product was purified using 10% ethyl acetate in hexanes to yield pure 0.4680 g (64% yield) of off-white solid 23: ¹H NMR (500 MHz, CDCl₃) δ 8.62 (d, J = 5.1 Hz, 1H), 8.02 (d, J = 16.0 Hz, 1H), 7.74 – 7.64 (m, 2H), 7.53 – 7.45 (m, 2H), 7.31 (d, J = 5.1 Hz, 1H), 7.10 (d, J = 16.0 Hz, 1H). ¹³C NMR (125 MHz, CDCl₃) δ 165.5, 161.5, 159.6, 139.3, 135.0, 129.9, 128.9, 127.9, 126.1, 124.0, 122.7, 116.8. HRMS (ESI⁺) m/z calcd for C₁₂H₁₀N₂Cl⁺ 217.0533, found 217.0532.