Iodoethane → 6-cyclopropyl-1-ethyl-1H-pyrazolo[3,4-b]pyridine-4-carboxylic acid

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Reaction Steps

To a solution of ethyl 6-cyclopropyl-1H-pyrazolo[3,4-b]pyridine-4-carboxylate (200 mg, 0.865 mmol) in DMF (10 mL) was carefully added sodium hydride (29.1 mg, 1.211 mmol). After 15 minutes stirring, iodoethane (0.077 mL, 0.951 mmol) was added and the mixture stirred at room temperature for 2 hr. Sodium hydroxide (1 mL, 1.000 mmol) was added and the mixture allowed to stir at room temperature for 1 h. The contents were concentrated in vacuo. The crude residue was diluted with water (50 mL) and acidified with acetic acid. The contents were then extracted with DCM (4×50 mL). The combined organic layers were washed with water, brine, dried over MgSO4, filtered and concentrated in vacuo. The crude product was purified by silica gel chromatography (eluent: hexanes to 100% EtOAc, then DCM to 20% MeOH:DCM). The final product was collected as 90 mg (45%). LCMS E-S (M+H)=232.1 1H NMR (400 MHz, DMSO-d6) δ ppm 1.06-1.17 (m, 4H) 1.41 (t, J=7.33 Hz, 3H) 2.35-2.45 (m, 1H) 4.34-4.57 (m, 2H) 7.62 (s, 1H) 8.24 (s, 1H) 13.83 (br. s., 1H). Regiochemical assignment supported by 2D HNMR.

Provenance & Evidence