[Cl:1][C:2]1[CH:10]=[CH:9][CH:8]=[C:7]([Cl:11])[C:3]=1[CH:4]=[N:5][OH:6].ClN1C(=O)CCC1=O.[CH3:20][CH:21]([CH2:30][CH3:31])[C:22](=O)[CH2:23][C:24](OCC)=[O:25].[O-]CC.[Na+].C(O)C.[H-].C([Al+]CC(C)C)C(C)C.C1(C)C=CC=CC=1.[C@H](O)(C([O-])=O)[C@@H](O)C([O-])=O.[Na+].[K+]>CN(C=O)C.O1CCCC1.C(=O)=O.ClCCl.CO.C(OCC)(=O)C.CCOCC>[Cl:1][C:2]1[CH:10]=[CH:9][CH:8]=[C:7]([Cl:11])[C:3]=1[C:4]1[C:23]([CH2:24][OH:25])=[C:22]([C@H:21]([CH3:20])[CH2:30][CH3:31])[O:6][N:5]=1To a solution of 2,6-dichlorobenzaldehyde oxime (26.4 g, 139 mmol) in DMF (70 mL) at 5° C. was added solid N-chlorosuccinimide (18.6 g, 139 mmol) in portions. The mixture was allowed to stir and warm to ambient temperature (with occasional cooling when warming was noted) over approximately 1.5 hour and then poured into ether. The organic layer containing the crude imidoyl chloride was washed twice with water followed by brine, dried over magnesium sulfate and concentrated. To a separate solution of ethyl 4-methyl-3-oxohexanoate (28.8 g, 167 mmol) in tetrahydrofuran (50 mL) at 0° C. was added a 21 wt % solution of sodium ethoxide in ethanol (62.3 mL, 167 mmol) quickly. The above imidoyl chloride was added dropwise in tetrahydrofuran (100 mL). The solution was allowed to stir while warming to ambient temperature overnight. The mixture was then poured into ether, washed twice with water followed by brine, dried over magnesium sulfate, concentrated and purified by chromatography (silica gel, 1.25% acetone in hexanes) to afford an oil which was dissolved in tetrahydrofuran (75 mL) at 0° C. Then a 1.5 M solution of diisobutylaluminum hydride in toluene (100 mL, 150 mmol) was added slowly. The solution was allowed to warm slightly while stirring for approximately 2.5 hours and then was re-cooled to 0° C. and stirred for 1.5 hours. Then approximately 20 mL of Rochelle's salt was added carefully followed by ethyl acetate and the mixture was stirred overnight. Then the layers were separated and the aqueous layer was extracted two more times with ethyl acetate. The combined organic layers were washed with brine, dried over magnesium sulfate, concentrated and purified by chromatography (silica gel, 20% ethyl acetate in hexanes) to afford a white solid. The enantiomers were resolved by supercritical fluid chromatography (Chiralpak AD, 10% methanol in supercritical carbon dioxide) and the resulting solid was taken up with dichloromethane, dried over magnesium sulfate and concentrated to afford {3-(2,6-dichlorophenyl)-5-[(1R)-1-methylpropyl]-4-isoxazolyl}methanol (1.35 g, 6%) 1H-NMR (400 MHz, DMSO-d6) δ 7.61-7.51 (m, 3H), 4.85 (t, J=5 Hz, 1H), 4.20-4.06 (m, 2H), 3.15-3.10 (m, 1H), 1.69-1.62 (m, 2H), 1.29 (d, J=7 Hz, 3H), 0.79 (t, J=7 Hz, 3H).
読み込み中…
