反应详情

A stirred solution of triethylamine (123 μl, 0.87 mmol) and 4-carboxymethoxypiperidine-1-carboxylic acid tert-butyl ester (Preparation 1, 227 mg, 0.87 mmol) in toluene (10 ml) was treated with isobutylchloroformate (113 μl, 0.87 mmol). After 20 min, activated powdered 3 Å molecular sieves (0.7 g) and N-hydroxyisonicotinamidine (100 mg, 0.73 mmol) were added and the mixture heated under reflux for 18 h. On cooling, the mixture was filtered through celite, the solvent removed in vacuo and the residue purified by flash chromatography (IH-EtOAc, 7:13) to afford the title compound: RT=3.29 min; m/z (ES+) 361.3 [M+H]+; δH (CDCl3) 1.40 (9H, s), 1.55-1.63 (2H, m), 1.80-1.92 (2H, m), 3.05-3.15 (2H, m), 3.64-3.79 (3H, m), 4.80 (2H, s), 7.90 (2H, d), 8.75 (2H, d).

1. additionwere added
2. temperaturethe mixture heated
3. temperatureunder reflux for 18 h
4. temperatureOn cooling
5. filtrationthe mixture was filtered through celite
6. customthe solvent removed in vacuo
7. customthe residue purified by flash chromatography (IH-EtOAc, 7:13)