Tetrahydrofuran → 3-[3-chloro-5-(2-methyl-2H-pyrazol-3-yl)-thiophen-2-yl]-8-(1-ethyl-propyl)-2,6-dimethyl-imidazo[1,2-b]pyridazine

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Reaction Steps

To a −78° C. solution of 1-methyl-1H-pyrazole (0.12 g, 1.45 mmol) and THF (4 mL) is added 1.6 M n-BuLi (0.91 mL, 1.45 mmol). After 45 minutes 0.5 M ZnCl2 (2.9 mL, 1.45 mmol) is added and the solution is warmed to ambient temperature. After 30 minutes 3-(5-bromo-3-chloro-thiophen-2-yl)-8-(1-ethyl-propyl)-2,6-dimethyl-imidazo[1,2-b]pyridazine (example Rupp-88) (0.30 g, 0.73 mmol) and PdCl2(dppf) (0.027 g, 0.036 mmol) are added and the solution heated at 65° C. overnight, diluted with EtOAc (30 mL), washed with sat. NH4Cl (2×30 mL), dried over MgSO4, filtered and concentrated. The residue is purified by ISCO column chromatography (15%-30% EtOAc/hexane gradient) furnish the title compound (0.15 g, 0.36 mmol, 50%). 1H NMR (CDCl3) δ 0.88 (d, J=7.5 Hz, 6H), 1.74-1.91 (m, 4H), 2.52 (s, 6H), 3.26-3.36 (m, 1H), 4.05 (s, 3H), 6.45 (d, J=1.9 Hz, 1H), 6.71 (s, 1H), 7.14 (s, 1H), 7.49 (d, J=1.9 Hz, 1H). LC/MS (m/z): calcd. for C21H24ClN5S (M+H)+: 414.2; found: 414.2.

Provenance & Evidence