Hydrazine hydrate (1:1) → tert-Butyl 4-(6-amino-7-fluoro-2H-benzo[b][1,4]thiazin-4(3H)-yl)piperidine-1-carboxylate

Participants

Reaction Steps

To a stirred solution of tert-butyl 4-(7-fluoro-6-nitro-2H-benzo[b][1,4]thiazin-4(3H)-yl)piperidine-1-carboxylate (190 mg, 0.478 mmol) in tetrahydrofuran (3.00 mL) was added Raney-Nickel (28.1 mg, 0.478 mmol) as a suspension in methanol (3 mL). To this mixture was then added hydrazine hydrate (0.233 mL, 4.78 mmol), and the resulting mixture was stirred at 60° C. for 8 minutes. During this time, the reaction mixture turns light red. The mixture was then diluted with ethyl acetate and washed with saturated sodium carbonate (2×), water (2×), and brine. The organic phase was dried, filtered, and concentrated, giving a red oil (172 mg, 98%). 1H NMR (DMSO-d6) δ 6.61 (d, J=11.1 Hz, 1H), 6.34 (d, J=8.4 Hz, 1H), 4.76 (s, 2H), 4.11-4.01 (m, 2H), 3.62-3.51 (m, 1H), 3.29-3.25 (m, 2H), 2.93-2.88 (m, 2H), 2.87-2.69 (m, 2H), 1.71-1.61 (m, 2H), 1.59-1.48 (m, 2H), 1.40 (m, 9H); ESI-MS (m/z, %): 368 (MH+, 25), 312 (100).

Provenance & Evidence