Hydrochloric Acid → 3-[8-(1-Ethyl-propyl)-2,6-dimethyl-imidazo[1,2-b]pyridazin-3-yl]-2-methyl-imidazo[1,2-a]pyridine-8-carboxaldehyde

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Reaction Steps

A solution of 3-(8-diethoxymethyl-2-methyl-imidazo[1,2-a]pyridin-3-yl)-8-(1-ethyl-propyl)-2,6-dimethyl-imidazo[1,2-b]pyridazine (2.33 g, 5.20 mmol) in acetone (25 mL) is treated with 5 M HCl (1.0 mL, 5 mmol) and the resulting solution is refluxed for 4 h. The organic solvent is removed in vacuo; the residue is diluted with H2O (100 mL), the pH is adjusted to 8-9 using sat. NaHCO3; the mixture is extracted with EtOAc (2×100 mL); dried with Na2SO4; filtered and concentrated, and purification of the crude material by silica gel chromatography gives the title compound (1.39 g, 3.72 mmol, 71%). 1H NMR (CDCl3): δ. 0.92 (t, J=7.5 Hz, 3H), 0.93 (t, J=7.5 Hz, 3H), 1.81-1.95 (m, 4H), 2.43 (s, 3H), 2.44 (s, 3H), 2.51 (s, 3H), 3.30-3.42 (m, 1H), 6.76 (s, 1H), 6.91 (t, J=7.0 Hz, 1H), 7.74 (dd, J=7.0, 1.3 Hz, 1H), 7.78 (dd, J=7.0, 1.3 Hz, 1H), 10.84 (s, 1H) ppm. ES-MS (m/z): calcd for C22H25N5O (M+H)+: 376.5. found: 376.2.

Provenance & Evidence