Acetic Acid → (E)-3-(2-(pyridin-3-yl)vinyl)-1H-indazole-6-carbaldehyde

Participants

Reaction Conditions

Reaction Steps

To a suspension of (E)-3-(2-(pyridin-3-yl)vinyl)-1H-indazole-6-carbonitrile (984 mg, 3 mmol) in pyridine (30 mL) was added HOAc (8 mL), followed by DMF (30 mL). The resulting mixture was heated and sonicated to make a clear solution. After cooling to 0° C., a solution of sodium hypophosphite (1.408 g, 16 mmol) in H2O (8 mL) was added, followed by Raney-Nickel 2400 (slurry in H2O, 0.8 mL). The resulting mixture was heated at 60° C. (oil temp.) for 1 h before cooling to rt. H2O (50 mL) was added and the mixture was extracted with EtOAc (100 mL+50 mL×2). The combined extracts were dried (Na2SO4). Removal of low boiling point solvents gave a yellow solution in DMF (30 mL); H2O (500 mL) was added with swirling and a yellow precipitate formed. After standing 10 min, the resulting precipitate was collected by suction filtration, rinsed with H2O and dried under high vacuum to give the title compound (500 mg, 50%) as a yellow solid. 1H NMR (400 MHz, DMSO-d6) δ 13.79 (s, 1H, NH), 10.14 (s, 1H, CHO), 8.90 (s, 1H), 8.48 (d, J=4.8 Hz, 1H), 8.39 (d, J=8.0 Hz, 1H), 8.19 (d, J=9.2 Hz, 1H, partially overlapping with the singlet at 8.18 ppm), 8.18 (s, 1H, partially overlapping with the doublet at 8.19 ppm), 7.75 (d, J=16.4 Hz, 1H), 7.69 (d, J=8.4 Hz, 1H), 7.59 (d, J=16.8 Hz, 1H), 7.43 (dd, J=8.0 Hz, 5.2 Hz, 1H); MS ESI 250.0 [M+H]+, calcd for [C15H11N3O+H]+ 250.1.

Provenance & Evidence