[Br:1][C:2]1[CH:3]=[C:4]([CH:12]=[CH:13][CH:14]=1)[NH:5][C:6](=[O:11])[CH2:7][C:8](=[O:10])[CH3:9].[CH:15]([O-])([O-])OC.N1C2C(=CC=CC=2)C=CC=1>C1(C)C=CC(S(O)(=O)=O)=CC=1.CO>[Br:1][C:2]1[CH:3]=[C:4]([CH:12]=[CH:13][CH:14]=1)[NH:5][C:6](=[O:11])/[CH:7]=[C:8](\[O:10][CH3:15])/[CH3:9]A mixture of 68.5 g of m-bromo-acetylacetanilide, 39.6 g of methyl orthoformate, 160 ml of methanol and 0.5 g of p-toluene sulfonic acid was stirred for 2 hours at 20° C and after the addition of 1 ml of quinoline, the mixture was evaporated to dryness under reduced pressure. The 83 g of colorless oil residue was taken up in 400 ml of toluene and the mixture was heated at 140° C for 4 hours while distilling the toluene-methanol azeotrope formed. After cooling, the toluene was evaporated under reduced pressure and the residue was chromatographed over silica gel. The product was eluted with a 9-1 mixture of methylene chloride and ethyl acetate and the fraction with an Rf = 0.65 was taken up in isopropyl ether to obtain 44 g of m-bromo-3-methoxy-crotonanilide melting at 110° C.
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