F[C:2]1[CH:10]=[CH:9][C:8]([S:11]([CH3:14])(=[O:13])=[O:12])=[CH:7][C:3]=1[C:4]([OH:6])=[O:5].C(=O)([O-])[O-].[Cs+].[Cs+].[CH3:21][CH:22]([SH:24])[CH3:23].Cl>CN(C)C(=O)C>[CH:22]([S:24][C:2]1[CH:10]=[CH:9][C:8]([S:11]([CH3:14])(=[O:13])=[O:12])=[CH:7][C:3]=1[C:4]([OH:6])=[O:5])([CH3:23])[CH3:21]To a solution of 4.58 mmol 2-fluoro-5-methanesulfonyl-benzoic acid (Example A14(b)) in 6 ml N,N-dimethylacetamide were added 15.2 mol cesium carbonate and 10.1 mmol 2-propanethiol and the mixture was stirred at 90° C. for 3 h. The reaction mixture was then cooled to room temperature and acidified to pH1 by addition of hydrochloric acid before being extracted three times with ethyl acetate. The combined organic phases were dried over sodium sulfate and concentrated in vacuo to afford the title compound as a light yellow liquid which was used in the next step without further purification (yield 99%). EI-MS (m/e): 274.1 (M+, 35%), 232.1 ([M−C3H6]+, 30%, 214.1 (M−C3H6−H2O)+, 100%).
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