Ethanol → HCID 58095018, compound

Participants

Reaction Steps

To a stirred solution of tert-butyl 3-(2-methylpyrazolo[1,5-a]pyridin-3-yl)-3-oxopropanoate (1.5 g, 5.47 mmol) prepared above and methyl 2-mercaptoacetate (4 mL, 40 mmol) in EtOH (4 mL), a stream of hydrogen chloride gas was bubbled at 0° C. for 2 h. After bubbling of hydrogen chloride gas was stopped, the mixture was stirred for 24 h at rt. The solvent was removed by evaporation. To the residue, were added a saturated aqueous solution of NaHCO3 (100 mL) and EtOAc (300 mL). The resulting biphasic mixture was vigorously stirred for 30 min and then aqueous phase was discarded. The organic phase was washed with brine and then dried over anhydrous magnesium sulfate. Insoluble materials were removed by filtration and the filtrate was concentrated under reduced pressure. To the residue was added a 20% solution of sodium ethylate in ethanol (50 mL) and the mixture was stirred for 16 h at rt. To the mixture, were added EtOAc (400 mL), a saturated aqueous solution of ammonium chloride and a 1N aqueous solution of hydrogen chloride to adjust ca pH 4-5. After being stirred for 30 min, the organic phase was washed with brine and then dried over anhydrous magnesium sulfate. Insoluble materials were removed by filtration and the filtrate was concentrated under reduced pressure. Column chromatography was performed to yield the title compound (381 mg, 23%) as a pale yellow solid. 1H NMR (300 MHz, d6-DMSO) δ: 10.31 (br s, 1H), 8.69 (d, J=6.8 Hz, 1H), 7.88 (d, J=9.1 Hz, 1H), 7.48-7.38 (m, 1H), 7.04-6.92 (m, 2H), 4.32-4.21 (m, 2H), 2.56 (s, 3H), 1.38-1.18 (m, 3H).

Provenance & Evidence