Nitric Acid → Ethyl 1-(1-methylethyl)-6-(2-nitrophenyl)-1H-pyrazolo[3,4-b]pyridine-4-carboxylate

Participants

Reaction Steps

Ethyl 1-(1-methylethyl)-6-phenyl-1H-pyrazolo[3,4-b]pyridine-4-carboxylate (120 mg, 0.388 mmol) was dissolved in concentrated nitric acid (1.7 mL) followed by addition of concentrated sulfuric acid (0.200 mL), and the reaction mixture was stirred at room temperature. After 40 min., the reaction mixture was cooled in an ice bath and with stirring was diluted with water (3 mL) and then slowly with saturated Na2CO3 (1 mL). The reaction mixture was extracted with EtOAc (2×6 mL). The combined organic layers were concentrated in vacuo and the crude product purified by silica gel chromatography (eluent: EtOAc/Hexanes, 0-70% gradient). The product, was collected as a white solid (35 mg, 26%). LCMS E-S (M+H)=355.2. 1H NMR (400 MHz, CHLOROFORM-d) 8.46 (s, 1H), 7.99 (s, 1H), 7.94 (dd, J=1.14, 7.96 Hz, 1H), 7.76-7.81 (m, 1H), 7.73 (td, J=1.26, 7.58 Hz, 1H), 7.59-7.66 (m, 1H), 5.25 (ddd, J=6.57, 6.69, 13.52 Hz, 1H), 4.51-4.59 (m, 2H), 1.61 (d, J=6.82 Hz, 6H), 1.52 (t, J=7.07 Hz, 3H).

Provenance & Evidence