Potassium Carbonate → 2-(Pyridin-2-yl)-3-(imidazo[1,2-a]pyridin-6-yl)-5,6-dihydro-4H-pyrrolo[1,2-b]pyrazole

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Reaction Steps

Add tetrakis(triphenylphosphine)palladium(0) (0.025 g, 0.022 mmol) to a microwave tube containing a solution of 6-bromo-imidazo[1,2-a]pyridine (0.086 g, 0.44 mmol), 2-pyridin-2-yl)-5,6-dihydro-4H-pyrrolo[1,2-b]pyrazole-3-boronic acid (Preparation 5; 0.1 g, 0.436 mmol), and 2M aqueous potassium carbonate (0.5 mL, 1 mmol) in dimethylsulfoxide (1.5 mL). Irradiate the reaction in a microwave reactor set at 111° C., 50 W., 10 min with internal cooling. Normal phase chromatography using ethyl acetate/methanol mixtures followed by reversed phase preparative chromatography gives the 0.05 g (38%) of the title compound as a white solid. MS (electrospray, m/z) 301.9 (M+1). 1H NMR (400 MHz, DMSO-d) δ 8.57 (s, 1H), 8.4 (d, J=4.8 Hz, 1H), 7.87 (s, 1H), 7.78 (m, 2H), 7.52 (s, 1H), 7.42 (d, J=9.2 Hz, 1H), 7.26 (m, 1H), 7.05 (dd, J=9.2, 2 Hz, 1H), 4.2 (t, J=6.6 Hz, 2H, 2.99 (t, J=6.6 Hz, 2H), 2.59 (m, 1H).

Provenance & Evidence