Water → 5-Methyl-2-(4-nitrobenzyl)-1,2,5-thiadiazolidine-1,1-dioxide

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Reaction Steps

To a stirred suspension of anhydrous potassium carbonate (14.49 g, 104.8 mmol) in anhydrous dimethylformamide (80 ml) was added dropwise over 4 minutes a solution of 2-methyl-1,2,5-thiadiazolidine-1,1-dioxide (14 g, 102.8 mmol) in anhydrous dimethylformamide (40 ml), under nitrogen. After 5 minutes, solid 4-nitrobenzyl bromide (22.43 g, 103.8 mmol) was added in one portion and stirring was continued at room temperature for 5 hours. Water (200 ml) was added and products were extracted into ethyl acetate (3×150 ml). The combined organic phases were washed with brine (1×50 ml), dried (Na2SO4) and concentrated. The crude residue was crystallized from ethyl acetate-hexane (70:30) to give 18.31 g (67%) of the title compound as pale yellow crystals. Purification of the mother liquors by flash chromatography (silica gel, hexane-ethyl acetate, 30:70) afforded a further 5.1 g (18.2%) of required product; mp 105°-107° C.; δH (250 MHz, CDCl3) 8.22 (2H, d, J=8.7 Hz, Ar--H), 7.57 (2H, d, J=8.7 Hz, Ar--H), 4.32 (2H, s, Ar--CH2 --), 3.36--3.21 (4H, m, N--CH2CH2 --N), 2.80 (3H, s, --NMe); m/z (CI) 270 (M+ -1).

Provenance & Evidence