Sodium hydride → 3-bromo-N-(5-cyanopyridin-2-yl)-N-(oxetan-3-yl)pyrazolo[1,5-a]pyridine-5-carboxamide

Participants

Reaction Steps

To a solution of 3-bromopyrazolo[1,5-a]pyridine-5-carboxylic acid (I-7, 240 mg, 1 mmol) in dichloromethane (10 mL) was added oxalyl chloride (0.25 mL) and catalytic amounts of anhydrous dimethylformamide at rt. The reaction mixture was stirred for 30 minutes and subsequently the solvent was removed under reduced pressure. To the residual acid chloride was added a solution of 6-(oxetan-3-ylamino)nicotinonitrile (I-25, 175 mg, 1 mmol) in dichloromethane (10 mL). The resulting reaction mixture was quickly transferred to a microwave vial and NaH (60% in mineral oil) (191 mg, 5 mmol) was added. The vial was heatedin a microwave oven at 80° C. for 3 h. The reaction mixture was diluted with dichloromethane (15 mL) and subsequently washed with water, sat. NaHCO3 solution and brine. The organic layer was dried over Na2SO4 and the solvent was removed under reduced pressure. The resulting crude product was purified by column chromatography over silica gel (chloroform/MeOH, 0-10% EtOAc) to afford 75 mg (20%) of 3-bromo-N-(5-cyanopyridin-2-yl)-N-(oxetan-3-yl)pyrazolo[1,5-a]pyridine-5-carboxamide (I-26) as a brown solid. 1H NMR (400 MHz, CDCl3) δ 8.45 (d, J=7.0 Hz, 1H), 8.16 (s, 1H), 8.02 (t, J=7.90 Hz, 1H), 7.53 (d, J=0.8 Hz, 1H), 7.33-7.31 (m, 1H), 6.90-6.87 (m, 1H), 6.43 (d, J=10.1 Hz, 1H), 4.67-4.62 (m, 1H), 4.52-4.43 (m, 2H), 4.25-4.19 (m, 1H), 4.03-3.98 (m, 1H); ESI-LC/MS (m/z): [M+H]+ 398.13, [(M+2)+H]+ 400.08, RT 1.25 min.

Provenance & Evidence