Cesium carbonate → 2-(2,6-Dichloro-3-(2-pyrrolidinoethoxy)phenylcarbonyloxymethyl)-4-(3-methylbutyl)-5-methyl-1,2,5-thiadiazolidin-3-one 1,1-dioxide hydrochloride

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Reaction Steps

To a solution of 2,6-dichloro-3-(2-pyrrolidinoethoxy)-benzoic acid cesium salt (prepared by reaction of the acid (1.045 g, 3.069 mmol) in 30 ml of methanol with Cs2CO3 (1.2 g) followed by removal of the solvent) in DMF was added 2-chloromethyl-4-(3-methylbutyl)-5-methyl-1,2,5-thiadiazolidin-3-one 1,1-dioxide (0.75 g; 1.86 mmol) at room temperature. The resulting solution was allowed to react at room temperature under nitrogen for 17 hours. The mixture was concentrated in vacuo and the residue was dissolved in 70% ethyl acetate in ether, filtered, and washed with sodium bicarbonate solution and dried over sodium sulfate. The organic solution was concentrated, the residual clear oil dissolved in 40 ml of ether and treated with ether/HCl. The salt was purified from methanol/ether to afford 2-(2,6-dichloro-3-(2-pyrrolidinoethoxy)phenylcarbonyloxymethyl)-4-(3-methylbutyl)-5-methyl-1,2,5-thiadiazolidin-3-one 1,1-dioxide hydrochloride (Formula I: Ar=2,6-Cl2 -3-(OCH2CH2 -1-pyrrolidinyl)phenyl; R1 =H; R2 =(CH2)2CH(CH3)2 ; R3 =CH3 ; as HCl salt) a solid, m.p. 161°-162° C.

Provenance & Evidence