6-fluoro-1-methyl-3-(tributylstannyl)-1H-indazole → methyl 2-(6-fluoro-1-methyl-1H-indazol-3-yl)-5-(pivaloyloxymethyl)-5H-pyrrolo[2,3-b]pyrazine-7-carboxylate

Participants

Reaction Conditions

Reaction Steps

To a stirred solution of 6-fluoro-1-methyl-3-(tributylstannyl)-1H-indazole (0.51 g, 0.616 mmol), methyl 2-bromo-5-(pivaloyloxymethyl)-5H-pyrrolo[2,3-b]pyrazine-7-carboxylate (0.18 g, 0.486 mmol) in 6 mL of DMF were added CuI (0.04 g, 0.21 mmol) and Pd(PPh3)4 (0.057 g, 0.045 mmol) in one portion under nitrogen at room temperature. Then the reaction mixture was degassed by bubbling nitrogen for 10 minutes and stirred at 90° C. under nitrogen for 16 hours. The solvent was evaporated at 70° C. under reduced pressure and the residue was purified by column chromatography (silica gel, 200-300 mesh, eluting with a mixture of ethyl acetate and petroleum ether (1:1, v/v) to give methyl 2-(6-fluoro-1-methyl-1H-indazol-3-yl)-5-(pivaloyloxymethyl)-5H-pyrrolo[2,3-b]pyrazine-7-carboxylate (0.182 g, 85.2%) as a yellow solid. LCMS: (M+H)+=440; 1H NMR (300 MHz, DMSO): δ 9.13 (s, 1H), 8.83-8.78 (m, 1H), 8.70 (s, 1H), 7.63 (dd, 1H, J1=9.6 Hz, J2=2.1 Hz), 7.23 (dt, 1H, J1=9.3 Hz, J2=2.1 Hz), 6.30 (s, 2H), 4.13 (s, 3H), 3.92 (s, 3H), 1.08 (s, 9H).

Provenance & Evidence