2,6-Dichlorobenzoic acid → 2-(2,6-Dichlorophenylcarbonyloxymethyl)-4-propyl-1,2,5-thiadiazolidin-3-one 1,1-dioxide

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Reaktionsschritte

The thallium salt of 2,6-dichlorobenzoic acid (0.96 g; 2.43 mmol, prepared from 0.46 g of 2,6-dichlorobenzoic acid and 0.605 g of TlOC2H5 in ethanol ) was added to a solution of 2-chloromethyl-4-propyl-1,2,5-thiadiazolidin-3-one 1,1-dioxide (0.5 g; 2.21 mmol) in DMF (10 ml) containing tetrabutylammonium bromide (70 mg; 0.22 mmol). The mixture was allowed to react at 50° C. for 15 hours and at 100° C. for an additional hour, and then cooled. The mixture was concentrated in vacuo and the residue was purified by flash chromatography (25%-30% ethyl acetate in hexane) to afford 0.24 g (29%) of 2-(2,6-dichlorophenylcarbonyloxymethyl)-4-propyl-1,2,5-thiadiazolidin-3-one 1,1-dioxide (Formula I: Ar=2,6-Cl2 -phenyl; R1 =H; R2 =propyl; R3 =H) as a solid, m.p.95°-97° C.

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