Potassium Carbonate → 2-Methoxy-6-(6-methoxy-4-((4-phenylthiazol-2-yl)methoxy)benzofuran-2-yl)imidazo[2,1-b][1,3,4]thiadiazole

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A suspension of 6-methoxy-2-(2-methoxyimidazo[2,1-b][1,3,4]thiadiazol-6-yl)benzofuran-4-ol (Example 1H, 0.080 g, 0.252 mmol) and 2-(bromomethyl)-4-phenylthiazole (0.128 g, 0.504 mmol) in N,N-Dimethylformamide (3 mL) was maintained under vacuum (10 mbar) for 5 minutes. The flask was then flushed with nitrogen and anhydrous freshly powdered (mortar and pestle) potassium carbonate (0.105 g, 0.756 mmol) was added all at once. The resulting mixture was stirred at room temperature with a few short sonication periods (˜1 min) for 1 hour. The heterogeneous mixture became almost homogeneous (except the potassium carbonate) after 10 min and started to precipitate again to a cream solid. The reaction mixture was quenched with 1N hydrochloric acid (2 mL) and then partitioned between dichloromethane (150 mL) and saturated sodium bicarbonate (20 mL). The organic phase was washed with brine, dried over anhydrous magnesium sulfate and concentrated in vacuo. The solid pale yellow residue was chromatographed on silica gel (2.5×6 cm, elution dichloromethane-ethyl acetate 0-2-5%) to give the title material (0.116 g, 94%) as a pale yellow solid. Crystallization in ethyl acetate (12 mL) provided the title material (0.086 g) as a pale yellow solid. LC (Method C): 2.474 min. HRMS (ESI) calcd for C24H9N4O4S2 [M+H]+ m/z 491.0842, found 491.0864. 1H NMR (CDCl3, 400 MHz) δ ppm: 3.86 (s, 3H), 4.22 (s, 3H), 5.54 (s, 2H), 6.48 (d, J=1.96 Hz, 1H), 6.75 (broad d, 1H), 7.15 (s, 1H), 7.32-7.39 (m, 1H), 7.41-7.49 (m, 2H), 7.53 (s, 1H), 7.87 (s, 1H), 7.90-7.95 (m, 2H).

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