2,2'-Bipyridine → methyl 6-bromo-1-cyclopropyl-1H-indole-4-carboxylate

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

In a oven dried 100 ml RBF equipped, stir bar, septum and Nitrogen inlet was added methyl 6-bromo-1H-indole-4-carboxylate (0.508 g, 2.0 mmol) and 1,2-dichloroethane (7 mL). The solution was stirred for 15 min, then cyclopropylboronic acid (0.344 g, 4.00 mmol) and sodium carbonate (0.424 g, 4.00 mmol) were added. Diluted copper(II) acetate (0.363 g, 2.000 mmol) and 2,2′-bipyridine (0.312 g, 2.000 mmol) in 1,2-dichloroethane (12 mL), heated the mixture, and added the hot suspension to the reaction. The reaction was heated at 70° C. and monitored by LCMS. Stopped heating after 6 h and allowed to sit for 3 days at RT. Added to reaction saturated NH4Cl and water. Extracted with DCM (2x). The combined organics were washed with brine, dried over magnesium sulfate, filtered and concentrated in vacuo. Purification of the residue by column chromatography (24 g Isco silica column; gradient B: 3-25%. A: hexane. B: ethyl acetate) to give methyl 6-bromo-1-cyclopropyl-1H-indole-4-carboxylate (0.43 g, 1.433 mmol, 71.6% yield) as a yellow residue. 1H NMR (400 MHz, DMSO-d6) δ ppm 0.96-1.01 (m, 2H) 1.06-1.12 (m, 2H) 3.52 (dt, J=7.20, 3.47 Hz, 1H) 3.90 (s, 3H) 6.85-6.91 (m, 1H) 7.57 (d, J=3.03 Hz, 1H) 7.82 (d, J=1.77 Hz, 1H) 8.04 (d, J=1.01 Hz, 1H). MS(ES) [M+H]+ 294.1.

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