[CH3:1][O:2][C:3]1[CH:4]=[C:5]([CH:10]=[C:11]([S:13]([F:18])([F:17])([F:16])([F:15])[F:14])[CH:12]=1)[C:6](OC)=[O:7].Cl.[CH3:20][NH:21][O:22][CH3:23].C([Mg]Br)(C)C>C1COCC1>[CH3:1][O:2][C:3]1[CH:4]=[C:5]([CH:10]=[C:11]([S:13]([F:16])([F:18])([F:17])([F:14])[F:15])[CH:12]=1)[C:6]([N:21]([O:22][CH3:23])[CH3:20])=[O:7]Methyl 3-methoxy-5-(pentafluorosulfanyl)benzoate (O4.007; 2.5 g) was dissolved in absolute THF (65 ml), and N,O-dimethylhydroxylamine hydrochloride (1.2 g) was added. Then the mixture was cooled to −15° C. and isopropylmagnesium bromide solution (13.59 ml, 2 M in THF) was added dropwise. After 20 min, the cooling bath was removed and the mixture was stirred at RT for 1 h. Then ammonium chloride solution was added and the aqueous phase was extracted three times with ethyl acetate. The combined extracts were dried over magnesium sulfate, filtered and concentrated. The crude product thus obtained still contained significant reactant, and was therefore converted and worked up again as described above. No reactant was present any longer in the residue which was then obtained. Purification was effected by means of preparative HPLC (met. A). The product-containing fractions were combined and freed of the acetonitrile, and the aqueous phase was extracted three times with EA. The combined extracts were dried over magnesium sulfate, filtered and concentrated. 1.78 g of the desired compound were obtained.
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