Thiophenol → Ethyl 4,5,6,7-tetrahydropyrazolo[1,5-a]pyrazine-2-carboxylate

Participants

Reaction Steps

To a mixture of ethyl 5-[(2-nitrophenyl)sulfonyl]-4,5,6,7-tetrahydropyrazolo[1,5-a]pyrazine-2-carboxylate (0.216 g, 0.568 mmol) and cesium carbonate (0.35 g, 1.1 mmol) was added a solution of benzenethiol (0.11 mL, 1.1 mmol) in acetonitrile (1 mL). The resulting reaction mixture was stirred at room temperature for 1 hour. The solvent was removed in vacuo and the residue applied directly to silica purification (5% MeOH/DCM with 1% Et3N) to afford Intermediate 17 as a white solid (0.093 g, 84%). LC-MS: (FA) ES+196; 1H NMR (400 MHz, CDCl3) δ 6.49 (s, 1H), 4.35 (q, J=7.1 Hz, 2H), 4.17-4.13 (m, 2H), 4.04 (s, 2H), 3.29-3.25 (m, 2H), 1.74 (s, 1H), 1.35 (t, J=7.1 Hz, 3H).

Provenance & Evidence