2-methyl-1,2,5-thiadiazolidine 1,1-dioxide

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:80.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Sodium hydride (0.128 g, 60% disp. in oil) was added to a stirred solution of 2-methyl-1,2,5-thiadiazolidine 1,1-dioxide (0.433 g) in THF (10 ml). DMF (10 ml) was added and the mixture heated at 80° C. for 5 min then a solution of the product from step (i) (0.8 g) in DMF (5 ml) was added. The mixture was heated at 60° C. for 10 min, poured into water (100 ml), acidified with citric acid and extracted with ethylacetate. The organics were evaporated under reduced pressure and the residue purified by chromatography on silica eluting with diethylether, yield 0.58 g. The mixture was heated at 60° C. for 10 min extracted with ethylacetate The organics were evaporated under reduced pressure the residue purified by chromatography on silica eluting with diethylether, yield 0.58 g

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of 2-methyl-1,2,5-thiadiazolidine-1,1-dioxide (2.02 g, 14.8 mmol) in anhydrous dimethylformamide (30 ml) was added sodium hydride (60% dispersion in oil; 0.59 g) and the mixture was stirred at room temperature under nitrogen for 40 minutes. A solution of 1-fluoro-4-nitrobenzene (2.09 g, 14.8 mmol) in anhydrous dimethylformamide (15 ml) was added to the above solution and the mixture was refluxed for 1 hour. Water (200 ml) was added and products were extracted with ethyl acetate (2×150 ml), dried (MgSO4) and concentrated to an orange solid. Crystallisation from ethyl acetate (150 ml) afforded 2.61 g (68.7%) of the title compound as a pale orange solid; mp 155°-163° C.; δH (250 MHz, DMSO-d6) 8.29 (2H, d, J=9.3 Hz, Ar--H), 7.34 (2H, d, J=9.3 Hz, Ar--H), 4.00 (2H, t, J=6.4 Hz, --CH2 --), 3.57 (2H, t, J=6.4 Hz, --CH2 --), 2.78 (3H, s, --CH3); m/z (EI) 257 (M+). the mixture was refluxed for 1 hour products were extracted with ethyl acetate (2×150 ml) dried (MgSO4) concentrated to an orange solid Crystallisation from ethyl acetate (150 ml)

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 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). was continued at room temperature for 5 hours products were extracted into ethyl acetate (3×150 ml) The combined organic phases were washed with brine (1×50 ml) dried (Na2SO4) concentrated The crude residue was crystallized from ethyl acetate-hexane (70:30)