反应详情

3-Phenyl-1-oxa-2-azaspiro[4.5]dec-2-ene-8-carboxylic acid (750 mg, 2.9 mmol) was slowly added to a solution of N-ethyldiisopropylamine (1.02 g, 7.1 mmol), 1-hydroxybenzotriazole hydrate (320 mg, 2.4 mmol), O-(benzotriazol-1-yl)-N,N,N′,N′-tetramethyluronium tetrafluoroborate (758 mg, 2.4 mmol) and 1-(3-chloropyridin-2-yl)piperazine (467 mg, 2.4 mmol) in abs. THF (17 ml). The reaction mixture was stirred overnight and the solvent removed under vacuum. The residue was taken up in EtOAc (100 ml). The precipitate formed was removed by suction-filtration. The organic phase was washed successively with sat. aq. NaCl solution, sat. aq. NaHCO3 solution, sat. aq. ammonium sulphate solution and sat. aq. NaCl solution, dried over magnesium sulphate and the solvent removed under vacuum. The precipitate and the residue were purified by column chromatography (silica gel, hexane/EtOAc 1:1). The desired product [4-(3-chloropyridin-2-yl)piperazin-1-yl]-(3-phenyl-1-oxa-2-azaspiro[4.5]dec-2-en-8-yl)methanone was obtained as a cis isomer (294 mg, 24% of the theoretical amount) and trans isomer (192 mg, 15% of the theoretical amount).

1. customthe solvent removed under vacuum
2. customThe precipitate formed
3. customwas removed by suction-filtration
4. washThe organic phase was washed successively with sat. aq. NaCl solution, sat. aq. NaHCO3 solution, sat. aq. ammonium sulphate solution and sat. aq. NaCl solution
5. dry with materialdried over magnesium sulphate
6. customthe solvent removed under vacuum
7. customThe precipitate and the residue were purified by column chromatography (silica gel, hexane/EtOAc 1:1)