Cesium carbonate → 5-chloro-3-(3,5-dimethyl-1H-1,2,4-triazol-1-yl)pyridazine

Beteiligte Stoffe

Reaktionsschritte

To a stirring solution of 3,5-dichloropyridazine (23-1, 5.00 g, 33.5 mmol, 1.0 eq.) in tetrahydrofuran (125 ml) at 0° C. was added cesium carbonate (17.7 g, 50.3 mmol, 1.5 eq.), followed by 3,5-dimethyl-1H-1,2,4-triazole (3.25 g, 33.5 mmol, 1.0 eq.) in tetrahydrofuran (125 mL) dropwise. The resulting reaction mixture was stirred for 1 hour at the same temperature and then warmed to room temperature and stirred for another 3 hours, then heated to 60° C. and stirred for 6 hours. The solvent was removed under reduced pressure and the residue was diluted with water (200 mL) and extracted with DCM (3×80 mL). The combined organic layers were dried over Na2SO4, filtered and concentrated. The residue was purified by silica gel column chromatography (70% ethyl acetate in hexanes) to afford 5-chloro-3-(3,5-dimethyl-1H-1,2,4-triazol-1-yl)pyridazine (23-2) as a white solid. 1H NMR (300 MHz, CDCl3) δ 9.11 (d, 1H, J=2.1 Hz), 8.20 (d, 1H, J=2.1 Hz), 2.96 (s, 3H), 2.43 (s, 3H).

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