[Cl:1][C:2]1[CH:10]=[CH:9][C:8]([S:11](Cl)(=[O:13])=[O:12])=[C:7]([Cl:15])[C:3]=1[C:4]([OH:6])=[O:5].[NH:16]1[CH2:21][CH2:20][CH2:19][CH2:18][CH2:17]1>C(Cl)Cl>[Cl:1][C:2]1[CH:10]=[CH:9][C:8]([S:11]([N:16]2[CH2:21][CH2:20][CH2:19][CH2:18][CH2:17]2)(=[O:13])=[O:12])=[C:7]([Cl:15])[C:3]=1[C:4]([OH:6])=[O:5]2,6-Dichloro-5-chlorosulfonylbenzoic acid (960 mg.; 3.3 m moles) is added portion-wise to 1.95 g. (0.0165 mole) of piperidine in 15 ml. of dry methylene chloride, and the mixture heated to reflux for 1.5 hrs. Th solvent and excess amine are removed under reduced pressure and the residue dissolved in 15 ml. of 2N sodium hydroxide. The aqueous base solution is extracted (2 × 50 ml.) with ether and acidified with 6N hydrochloric acid. The precipitated gum is filtered, dried and allowed to crystallize in hexane, 1.1 g., m.p. 145°-150° C. A small sample is recrystallized from acetonitrile, m.p. 142°-145° C.
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