Potassium Carbonate → Tert-butyl 4-[4-[6-amino-5-(1,3-benzoxazol-2-yl)-3-pyridyl]-3-formyl-pyrazol-1-yl]piperidine-1-carboxylate

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Reaction Steps

A suspension of 3-(1,3-benzoxazol-2-yl)-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridin-2-amine (0.3 g), tert-butyl 4-(4-bromo-3-formyl-pyrazol-1-yl)piperidine-1-carboxylate (0.362 g), potassium carbonate (0.335 g) and tetrakis(triphenylphosphine) palladium (0.093 g) in degassed acetonitrile (50 mL) was stirred at reflux overnight. The resulting suspension was cooled to room temperature, filtered, washed with dichloromethane (3×20 ml) and the filtrate concentrated and the crude product was purified by flash chromatography on silica gel eluting with 5 to 90% ethyl acetate in petroleum ether. The solvent was evaporated to dryness to afford tert-butyl 4-[4-[6-amino-5-(1,3-benzoxazol-2-yl)-3-pyridyl]-3-formyl-pyrazol-1-yl]piperidine-1-carboxylate (0.370 g) as a solid. NMR Spectrum: (DMSOd6) 1.44 (s, 9H), 1.87 (dd, 1H), 1.92 (dd, 1H), 2.09-2.18 (m, 2H), 2.97 (bs, 2H), 4.04-4.16 (m, 2H), 4.52-4.61 (m, 1H), 7.41-7.49 (m, 2H), 7.80 (dd, 1H), 7.82 (bs, 2H), 7.85 (dd, 1H), 8.48 (s, 1H), 8.56 (d, 1H), 8.65 (d, 1H), 9.99 (s, 1H); Mass spectrum: M+H+ 489.

Provenance & Evidence