F[C:2](F)(F)[C:3]([OH:5])=O.[NH2:8][C:9]1[CH:10]=[C:11]([C:21](=[O:23])[CH3:22])[CH:12]=[C:13]([S:15]([F:20])([F:19])([F:18])([F:17])[F:16])[CH:14]=1.C(N(CC)CC)C.C(OC(=O)C)(=O)C>C(Cl)Cl>[C:21]([C:11]1[CH:10]=[C:9]([NH:8][C:3](=[O:5])[CH3:2])[CH:14]=[C:13]([S:15]([F:16])([F:20])([F:17])([F:18])[F:19])[CH:12]=1)(=[O:23])[CH3:22]1-[3-Amino-5-(pentafluorosulfanyl)phenyl]ethanone trifluoroacetic acid salt (100 mg, example 4d) was dissolved in methylene chloride (10 ml), and triethylamine (120 μl) was added. Acetic anhydride (30 μl) was then added dropwise while stirring. After stirring for 4 h, the mixture was left to stand overnight and then further acetic anhydride (30 μl) was added. After stirring for a further 6 h, the reaction mixture was again left to stand overnight and then concentrated. The residue was taken up with ethyl acetate and water, and adjusted to pH 9 with saturated sodium hydrogencarbonate solution, and the aqueous phase was extracted twice more with ethyl acetate. The combined extracts were dried over magnesium sulfate, filtered and concentrated. 80 mg of the desired compound were obtained.
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