Tetrahydrofuran → 3-(3-Chloro-thiophen-2-yl)-8-(1-ethyl-propyl)-2,6-dimethyl-imidazo[1,2-b]pyridazine

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Reaction Steps

To a flask of 2-bromo-3-chloro-thiophene (Lemaire et. el., Synth. Commun., 1994, 24, 95) (2.53 g, 12.82 mmol) is added 0.05 g/mL Reike® zinc in THF (25 mL, 19.24 mmol). The solution is heated at a reflux for 2 hours. The excess zinc is allowed to settle and the solution transferred to a flask containing 8-(1-ethyl-propyl)-3-iodo-2,6-dimethyl-imidazo[1,2-b]pyridazine (example KW1-A03735-193) (2.01 g, 6.41 mmol) and PdCl2(dppf) (0.23 g, 0.32 mmol). The solution is heated at a reflux overnight, quenched with sat. NH4Cl (25 mL) and extracted with EtOAc (2×25 mL). The combined organic layers are dried over MgSO4, filtered and concentrated. The residue is purified by ISCO column chromatography (2%-15% EtOAc/hexane gradient) furnish the title compound (1.32 g, 6.68 mmol, 62%). 1H NMR (CDCl3), δ 0.87 (t, J=7.5 Hz, 6H), 1.74-1.91 (m, 4H), 2.48 (s, 3H), 2.49 (s, 3H), 3.37-3.36 (m, 1H), 6.67 (s, 1H), 7.07 (d, J=5.4 Hz, 1H), 7.48 (d, J=5.4 Hz, 1H). LC/MS (m/z): calcd. for C17H20ClN3S (M+H)+: 334.1; found: 334.1.

Provenance & Evidence