[F:1][C:2]1[CH:14]=[CH:13][C:5]([C:6]([CH2:8][C:9]([O:11][CH3:12])=[O:10])=[O:7])=[CH:4][CH:3]=1.[C:15](#[N:19])[CH:16]([CH3:18])[CH3:17].[Sn](Cl)(Cl)(Cl)Cl.O>C1(C)C=CC=CC=1.C(OCC)(=O)C>[NH2:19][C:15]([CH:16]([CH3:18])[CH3:17])=[C:8]([C:6]([C:5]1[CH:4]=[CH:3][C:2]([F:1])=[CH:14][CH:13]=1)=[O:7])[C:9]([O:11][CH3:12])=[O:10]39.2 g of methyl 4-fluorobenzoylacetate (0.20 mmol) and 16.8 g of isobutyronitrile (0.24 mol, concentration >99%) were dissolved in 200 ml of toluene and treated with 57.9 g of tin tetrachloride (0.22 mmol, concentration >99%) at room temperature after the course of 10 minutes. After 30 min at room temperature, the mixture was heated to 80° C. After 8 h, the suspension was again cooled to room temperature and treated with 200 ml of water. The mixture was diluted with 200 ml of ethyl acetate and the phases were separated. The organic phase was washed twice with 40 ml of 1N sodium hydroxide solution and concentrated in vacuo (40° C./25 mbar) after drying over magnesium sulphate. 50.9 g of crude product were obtained in the form of a yellow oil. After chromatography of 12.0 g of crude product on silica gel (eluent: hexane/isopropanol 90:10), 10.08 g of methyl 3-amino-2-[1-(4-fluorophenyl)methanoyl]-4-methylpent-2-enoate were obtained in the form of a yellowish oil.
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