反应详情

A 250 mL RB flask was charged with quinoline-6-carboxylic acid (5.00 g, 28.9 mmol), DCM (100 ml, 1554 mmol), oxalyl chloride (3.79 ml, 43.3 mmol), and a few drops of DMF and stirred at RT for 2 hours, then concentrated. The residue was taken up in DCM (100 ml, 1554 mmol), cooled to 0° C., then Hunig's Base (17.7 ml, 101 mmol) and N-methoxymethanamine hydrochloride (2.96 g, 30.3 mmol) were added slowly. The mixture was stirred at room temperature for 16 hours (91463-3-1). The mixture was diluted with DCM (200 mL), then washed with water (250 mL), sat. NaHCO3 (250 mL), and brine (250 mL). The organic layer was dried with MgSO4, filtered, and concentrated to give a brown oil, which was purified by MPLC eluting with 2-6% MeOH/DCM to give N-methoxy-N-methylquinoline-6-carboxamide (5.943 g, 95.2% yield) as a brown oil. b) 1-(quinolin-6-yl)ethanone A 250 mL RB flask was charged with N-methoxy-N-methylquinoline-6-carboxamide (5.943 g, 27.5 mmol) and THF (100 ml, 1220 mmol), then cooled to 0 C. Methylmagnesium bromide (18.3 ml, 55.0 mmol) was added dropwise and the mixture was allowed to warm to room temperature and stirred for 3 hours. The reaction was not quite complete, so additional MeMgBr (3 mL) was added and the mixture was stirred overnight. The mixture was then neutralized using 2N HCl and the aqueous layer was extracted with DCM (200 mL×2) and EtOAc (200 mL×2). The organic layer was dried with MgSO4, filtered, and concentrated to give a yellow oil. The aqueous layer contained some product, so the layer was concentrated and then filtered thru a reverse phase C18 column, first eluting with water than with MeOH. The MeOH layer was concentrated to give a yellow oil which was combined with the yellow oil from the organic layer. The combined portions were purified by MPLC eluting with a gradient of 2-6% MeOH/DCM. 1-(quinolin-6-yl)ethanone (4.074 g, 86.6% yield) was isolated as a yellow oil which solidified upon standing. c) 2-bromo-1-(quinolin-6-yl)ethanone Hydrobromide A 250 mL RB flask was charged with 1-(quinolin-6-yl)ethanone (3.82 g, 22.3 mmol) and 30% HBr/AcOH (45.0 ml). Bromine (1.14 ml, 22.1 mmol) was added slowly. This was stirred at room temperature for 4 hours, at which point full conversion to product (with a small amount of dibrominated side product) was observed. The reaction mixture was filtered and the solid was washed with Et2O to give 2-bromo-1-(quinolin-6-yl)ethanone hydrobromide (5.6359 g, 76.3% yield). The compound was used in the next step without further purification. d) (E)-N′-(6-chloropyridazin-3-yl)-N,N-dimethylformamidine A 500 mL RB flask was charged with 6-chloropyridazin-3-amine (10.0 g, 77.2 mmol) and dimethoxy-N,N-dimethylmethanamine (206 ml, 1544 mmol), equipped with a reflux condenser, then heated to 110° C. for 3 hours then left at room temperature for 16 hours. The precipitate was collected by filtration. The mother liquor was concentrated down to give an yellow solid, which was triturated with EtOAc and collected. The solids were combined to give (E)-N′-(6-chloropyridazin-3-yl)-N,N-dimethylformamidine (11.81 g, 82.9% yield) as a white solid e) (6-Chloroimidazo[1,2-b]pyridazin-3-yl)(quinolin-6-yl)methanone A 100 mL RB flask was charged with 2-bromo-1-(quinolin-6-yl)ethanone (0.7011 g, 2.80 mmol), (E)-N′-(6-chloropyridazin-3-yl)-N,N-dimethylformamidine (0.518 g, 2.80 mmol), and DMF (10.0 ml, 129 mmol), equipped with a reflux condenser, then heated at 105° C. for 3 hours. The reaction mixture was concentrated, then triturated with MeOH to yield (6-chloroimidazo[1,2-b]pyridazin-3-yl)(quinolin-6-yl)methanone (0.530 g, 1.72 mmol, 61%) as a brown solid. f) (6-Phenylimidazo[1,2-b]pyridazin-3-yl)(quinolin-6-yl)methanone A 48 mL sealed tube was charged with (6-chloroimidazo[1,2-b]pyridazin-3-yl)(quinolin-6-yl)methanone (0.530 g, 1.72 mmol), phenylboronic acid (0.314 g, 2.58 mmol), cesium carbonate (1.68 g, 5.15 mmol), PdCl2(dppf)-CH2Cl2 adduct (0.0701 g, 0.0858 mmol), 1,4-dioxane (6.31 ml, 73.8 mmol), and water (1.11 ml, 61.8 mmol), flushed with argon, sealed, then placed in an 80° C. oil bath for 8 hours. The mixture was concentrated then triturated with water, followed by MeOH/DCM to give (6-phenylimidazo[1,2-b]pyridazin-3-yl)(quinolin-6-yl)methanone as a reddish brown solid. g) 1-(6-Phenylimidazo[1,2-b]pyridazin-3-yl)-1-(quinolin-6-yl)ethanol A 25 mL RB flask was charged with (6-phenylimidazo[1,2-b]pyridazin-3-yl)(quinolin-6-yl)methanone (0.200 g, 0.57 mmol) and THF (2.00 ml, 24 mmol), then cooled to 0° C. methylmagnesium bromide (0.76 ml, 2.2 mmol) was added dropwise and the mixture was stirred at room temperature for 5 hours. This was diluted with 2 N HCl (1 mL) and water (25 mL), then extracted with DCM (25 mL×2) and EtOAc (25 mL). The combined organics were washed with brine and dried with MgSO4, filtered, and concentrated. The resulting oil was purified by MPLC using a 40 g RediSep column, eluting with 2-6% MeOH/DCM over 40 minutes. 1-(6-phenylimidazo[1,2-b]pyridazin-3-yl)-1-(quinolin-6-yl)ethanol (0.082 g, 39% yield) was isolated as a tan solid. MS (ESI pos. ion) m/z: 367 (MH+). Calc'd exact mass for C23H18N4O: 366.

1. concentrationconcentrated
2. temperaturecooled to 0° C.
3. washwashed with water (250 mL), sat. NaHCO3 (250 mL), and brine (250 mL)
4. dry with materialThe organic layer was dried with MgSO4
5. filtrationfiltered
6. concentrationconcentrated
7. customto give a brown oil, which
8. customwas purified by MPLC
9. washeluting with 2-6% MeOH/DCM