COC(=O)[C:4]1[CH:5]=[CH:6][CH2:7][C:8](F)([N+:10]([O-:12])=[O:11])[CH:9]=1.Cl.[CH3:16][NH:17][CH3:18].[C:19](=[O:22])([O-])[O-:20].[K+].[K+].[CH3:25]S(C)=O>>[CH3:25][O:20][C:19](=[O:22])[C:7]1[CH:6]=[C:5]([N:17]([CH3:18])[CH3:16])[CH:4]=[CH:9][C:8]=1[N+:10]([O-:12])=[O:11]To a stirred solution of 4.48 g (22.5 mmol) 5-Fluoro-5-nitro-benzoic acid methyl ester (Rarechem) and 60.0 ml dimethylsulphoxid were added 2.23 g (27.0 mmol) dimethylamine hydrochloride and 6.54 g (47.3 mmol) potassium carbonate. The reaction mixture was stirred for 8 h at 60° C. in an autoclave and was reduced with high vacuum rotation evaporator at 65° C. The residue was diluted with dichloromethane, washed twice with water. The combined water phases were extracted with dichloromethane. The combined dichloromethane phases were washed with diluted sodium hydrogen carbonate solution, dried with sodium sulphate and concentrated. The oily crude was purified by column chromatography and the desired product 19a was obtained in 69% yield (3.49 g, 15.5 mmol).
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