反应详情

Using a method similar to preparation 28, using 4-(3-bromo-phenoxy)-piperidine-1-carboxylic acid tert-butyl ester (preparation 14, 5.01 g, 14.07 mmol) gives 6.42 g of the corresponding 4-[3-(benzhydrylidene-amino)-phenoxy]-piperidine-1-carboxylic acid tert-butyl ester. Add sequentially sodium acetate (anhydrous, 2.77 g, 33.78 mmol) and hydroxylamine hydrochloride (1.76 g, 25.33 mmol) to a stirred solution of 4-[3-(benzhydrylidene-amino)-phenoxy]-piperidine-1-carboxylic acid tert-butyl ester (6.42 g, 14.07 mmol) in methanol (anhydrous, 140 mL) and stir at ambient room temperature. After 1 hr., dilute with dichloromethane (40 mL) and wash with sodium hydroxide (aq. 0.1 N, 60 mL), extract with dichloromethane (2×60 mL), dry over magnesium sulfate, filter under reduced vacuum and concentrate to dryness. Purify by flash chromatography (20-60% ethyl acetate/hexanes) to give the title compound as a pale yellow solid (3.85 g, 93%, 2 steps). Mass spectrum (ion spray): m/z=237.1 (M+1); 1H NMR (CDCl3): 7.04 (t, J=8.0 Hz, 1H), 6.34-6.26 (m, 3H), 4.41 (septet, J=3.5 Hz, 1H), 3.72-3.64 (m, 2H), 3.32 (ddd, J=3.9 Hz, 7.7 Hz, 13.2 Hz, 2H), 1.93-1.84 (m, 2H), 1.77-1.68 (m, 2H), 1.46 (s, 9H).

1. washwash with sodium hydroxide (aq. 0.1 N, 60 mL)
2. extractionextract with dichloromethane (2×60 mL)
3. dry with materialdry over magnesium sulfate
4. filtrationfilter under reduced vacuum
5. concentrationconcentrate to dryness
6. customPurify by flash chromatography (20-60% ethyl acetate/hexanes)