2,6-Dichlorobenzoic acid → 2-(2,6-dichlorophenylcarbonyloxymethyl) tetrahydropyrrolo[1,2-b]-1,2,5-thiadiazol-3(2H)-one 1,1-dioxide

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Reaction Steps

To a solution of CS2CO3 (0.47 g; 1.44 mmol) in 10 ml of methanol was added 0.55 g (2.88 mmol) of 2,6-dichlorobenzoic acid and the resulting mixture was stirred under nitrogen at room temperature for 3 hours. The above mixture was concentrated in vacuo to remove the excess methanol, the residue suspended in 10 ml of DMF and 2-chloromethyl-tetrahydropyrrolo[1,2-b]-1,2,5-thiadiazol-3 (2H)-one 1,1-dioxide (0.5 g; 2.6 mmol) was added. The resulting mixture was allowed to react at 90° C. for 3 hours and then cooled. The mixture was poured into ice/water, extracted with ether/ethyl acetate (3:1; 250 ml), and the organic layer was washed with water and brine, and dried. The organic layer was concentrated in vacuo and the residue was purified by silica gel flash chromatography (35% ethyl acetate in hexane) to afford 0.6 g (61%) of 2-(2,6-dichlorophenylcarbonyloxymethyl) tetrahydropyrrolo[1,2-b]-1,2,5-thiadiazol-3(2H)-one 1,1-dioxide (Formula I: Ar=2,6-Cl2 -phenyl; R1 =H; R2 and R3 together =-(CH2)3 -) as a solid, m.p. 92°-93.5° C.

Provenance & Evidence