反应详情

A mixture of tert-butyl 4-oxo-3,4-dihydro-2H-spiro[naphthalene-1,4′-piperidine]-1′-carboxylate A (1.24 g, 3.93 mmol), hydroxylamine hydrochloride (1.37 g, 19.7 mmol) and sodium acetate trihydrate (3.20 g, 23.5 mmol) in ethanol (50 ml) was heated under reflux for 20 h. The reaction was concentrated and the residue was suspended in water, extracted with dichloromethane (3×). The combined extracts were dried over Na2SO4 and concentrated to give tert-butyl 4-(hydroxyimino)-3,4-dihydro-2H-spiro[naphthalene-1,4′-piperidine]-1′-carboxylate B (1.32 g). LC-MS: m/e=331.1 (M+H, 100%), 275.0 (M+H−C(CH3)3). Rt=3.35 min. 1H-NMR (500 MHz, CDCl3): 8.01 (d, 0.25H), 7.93 (d, 0.75H), 7.41-7.34 (m, 2H), 7.23-7.19 (m, 1H), 3.95-3.92 (m, 2H), 3.04-2.96 (m, 2H), 2.87 (t, 0.5H), 2.82 (t, 1.5H), 2.3 (br. s, 1H), 1.93-1.84 (m, 4H), 1.54-1.52 (d, 2H), 1.43 (s, 9H).

1. temperaturewas heated
2. temperatureunder reflux for 20 h
3. concentrationThe reaction was concentrated
4. extractionextracted with dichloromethane (3×)
5. dry with materialThe combined extracts were dried over Na2SO4
6. concentrationconcentrated