反応手順
A mixture of ethyl 5-bromonicotinate (500 mg, 2.17 mmol, 1 equiv), 4,4,4′,4′,5,5,5′,5′-octamethyl-2,2′-bi-1,3,2-dioxaborolane (662 mg, 2.61 mmol, 1.20 equiv), potassium acetate (639 g, 6.51 mmol, 3.00 equiv), and 1,1′-bis (diphenylphophino)-ferrocene)dichloropalladium (89 mg, 0.11 mmol, 0.050 equiv) in DMF (5 mL) was heated at 80° C. for 16 hours. The mixture was partitioned between water (100 mL) and ethyl acetate (2×50 mL). The organic layer was dried over sodium sulfate and concentrated. A solution of the residue, 3-iodo-6-(4-methoxyphenyl)pyrazolo[1,5-a]pyrimidine (2-1, 254 mg, 0.723 mmol, 0.333 equiv), tetrakis(triphenylphosphine)palladium (50 mg, 0.043 mmol, 0.020 equiv) in a mixture of aqueous 2M sodium carbonate solution (1 mL) and dioxane (10 mL) was heated at reflux for 16 hours. The reaction was then partitioned between water (50 mL) and ethyl acetate (2×50 mL). The organic layer was dried over sodium sulfate and concentrated. The residue was suspended in methanol and filtered to give ethyl 5-[6-(4-methoxyphenyl)pyrazolo[1,5-a]pyrimidin-3-yl]nicotinate (2-2) as a yellow solid. 1H NMR (400 MHz, CDCl3) δ 9.50 (d, 1H, J=2.2 Hz), 9.12 (d, 1H, J=2.2 Hz), 8.96 (t, 1H, J=2.2 Hz), 8.88 (d, 1H, J=2.2 Hz), 8.8.3 (d, 1H, J=2.4 Hz), 8.54 (s, 1H), 7.56 (d, 2H, J=8.8 Hz), 7.08 (d, 2H, J=8.8 Hz), 4.48 (q, 2H, J=7.3 Hz), 3.90 (s, 3H), 1.46 (t, 3H, J=7.1 Hz).
