63% |
With caesium carbonate;palladium diacetate; 4,5-bis(diphenylphos4,5-bis(diphenylphosphino)-9,9-dimethylxanthenephino)-9,9-dimethylxanthene; In N,N-dimethyl-formamide; at 110℃; for 18h;Sealed tube; |
In a sealed tube, cesium carbonate (1.95 g, 6.00 mmol), tert-butyl-4-thiazolecarboxylate (556 mg, 3.00 mmol; prepared according to the procedure described in Organic Letters, 2008, 10(13), 2909), palladium(II) acetate (47 mg, 0.21 mmol) and 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene (240 mg, 0.42 mmol) were combined with <strong>[38696-20-7]5-bromo-2-phenylpyrimidine</strong> (705 mg, 3.00 mmol) in dry DMF (11 mL) and the mixture heated at 110° C. for 18 hours with stirring. The mixture was cooled to room temperature and filtered through Celite washing with hot ethyl acetate. Solvent was removed under reduced pressure and the residue purified by silica gel flash chromatography (9:1 to 3:2 v/v hexane-ethyl acetate gradient) through a 40-g Silicycle.(R). flash silica cartridge. The title compound was obtained as a white solid (646 mg, 63percent yield); Rf 0.75 with 1:1 v/v hexane-ethyl acetate; 1H-NMR (300 MHz; CDCl3) delta 9.37 (s, 2H), 8.52 (dd, 2H), 8.15 (s, 1H), 7.54 (m, 3H), 1.64 (s, 9H); MS (ESI+) m/z 340 (M+1); H-PGDS FPBA IC50: 5.9 muM. |