Acetic Acid → ethyl 5-(4-chlorophenylsulfonyl)-4,5-dihydro-1H-pyrazolo[4,3-c]pyridine-4-carboxylate

Participants

Reaction Steps

A flask was charged with compound 104 (5.8 g, 14.6 mmol), acetic acid (10 mL) and EtOH (10 mL). Hydrazine hydrate (1.4 mL, 30 mmol) was added and the reaction stirred at room temperature for 2 hours. The reaction mixture was concentrated in vacuo and the residue was taken up in EtOAc. The organic layer was washed with sat. aq. NaHCO3, brine, dried over Na2SO4, filtered, and concentrated in vacuo to yield crude material that was purified by flash chromatography (50% EtOAc/hexanes) to yield 1.63 g (30%) of compound 105 as a yellow foam. 1H NMR (CDCl3) δ 7.76 (d, J=6.3 Hz, 2H), 7.48-7.41 (m, 3H), 6.90-6.87 (m, 1H), 5.96-5.93 (m, 1H), 5.80 (s, 1H), 4.13-4.11 (m, 2H), 1.24-1.18 (m, 3H; MS (m/z) 368.0 (M+H)+.

Provenance & Evidence