[CH3:1][O:2][C:3](=[O:11])/[C:4](/[CH3:10])=[CH:5]\[C:6]([O:8][CH3:9])=[O:7].[Br:12]N1C(=O)CCC1=O>C(Cl)(Cl)(Cl)Cl.N(C(C)(C)C#N)=NC(C)(C)C#N>[CH3:1][O:2][C:3](=[O:11])/[C:4](/[CH2:10][Br:12])=[CH:5]/[C:6]([O:8][CH3:9])=[O:7]To a solution of (Z)-2-methyl-2-butenedioic acid dimethyl ester (15.3 g) in carbon tetrachloride (300 ml) were added N-bromosuccinimide (25.8 g) and 2,2′-azobis(isobutyronitrile) (319 mg), and the mixture was stirred for 36 hours at reflux. After cooling the mixture to room temperature, the insoluble substance was filtered off, and the filtrate was concentrated. The resulting residue was purified by silica gel column chromatography (eluent: n-hexane/ethyl acetate=1/0 to 18/1) to give the titled compound (19.6 g).
Wird geladen…
