Cesium fluoride → methyl 4-acetamido-3-chloro-6-(7-fluoro-1H-indol-6-yl)picolinate

Beteiligte Stoffe

Reaktionsschritte

Methyl 4-acetamido-3,6-dichloropicolinate (400 mg, 1.520 mmol), 7-fluoro-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-indole (437 mg, 1.673 mmol), cesium fluoride (462 mg, 3.04 mmol), and (PPh3)2PdCl2 (107 mg, 0.152 mmol) were charged as solids into a microwave reaction vessel and dioxane (4 mL) and water (1 mL) were added. The reaction vessel sealed and irradiated in a Biotage Initiator microwave at 110° C. for 2 h, with external IR-sensor temperature monitoring from the side. The reaction mixture was partitioned between ethyl acetate and water. The organic phase was filtered and concentrated. The intermediate product was purified by flash chromatography (ISCO 40 g silica 10-75% EtOAc: Hex 16 CV). Fractions containing product were combined and concentrated to give 524 mg of a white solid intermediate methyl 4-acetamido-3-chloro-6-(7-fluoro-1H-indol-6-yl)picolinate (0.524 g, 1.448 mmol) which was subsequently diluted with methanol (10.0 mL). Then acetyl chloride (0.725 mL, 10.20 mmol) was added. The reaction mixture was allowed to stir at room temperature for 18 h. The reaction was concentrated to dryness. The resulting residue was dissolved in ethyl acetate and poured into saturated NaHCO3 solution. The layers were partitioned and the aqueous layer was extracted with ethyl acetate (3×15 mL). The organic extracts were combined, washed with saturated NaCl solution, dried (MgSO4), filtered and concentrated in vacuo. The crude product was purified using a Teledyne ISCO purification system with a gradient eluent system of ethyl acetate and hexanes to yield the title compound as a white solid (365 mg, 79%).

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