3,3-dimethyl-1,2,5-thiadiazolidine 1,1-dioxide

Conditions: temp:40.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a stirred solution of 3,3-dimethyl-1,2,5-thiadiazolidine-1,1-dioxide (2.5 g, 16.6 mmol) in anhydrous dimethylformamide (50 ml) was added sodium hydride (60% dispersion in oil; 666 mg) in two portions. After being stirred at 40° C. for 50 minutes under nitrogen, the mixture was allowed to cool to room temperature, diluted with anhydrous dimethylformamide (20 ml) and treated with di-tert-butyldicarbonate (3.99 g, 18.26 mmol). After 1 hour 45 minutes of stirring at room temperature, the mixture was diluted with water (200 ml) and extracted with diethyl ether (3×100 ml). The organic phases were washed with brine (2×50 ml), dried (MgSO4) and concentrated. Flash chromatography of the residue (silica gel, dichloromethane to dichloromethane-diethyl ether 50:50) gave a mixture of the required product and 2,5-di-tert-butyloxycarbonyl-3,3-dimethyl-1,2,5-thiadiazolidine-1,1-dioxide. Trituration of this mixture with hot hexane afforded 1.26 g (30%) of the required title compound as a white solid; δH (250 MHz, CDCl3) 4.39 (1H, br s, --NH--), 3.70 (2H, s, --CH2 --), 1.54 (9H, s, t-Bu), 1.47 (6H, s, --CMe2); m/z (CI) 249 (M+ -1). to cool to room temperature After 1 hour 45 minutes of stirring at room temperature extracted with diethyl ether (3×100 ml) The organic phases were washed with brine (2×50 ml) dried (MgSO4) concentrated Flash chromatography of the residue (silica gel, dichloromethane to dichloromethane-diethyl ether 50:50) gave

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

Procedure: To a refluxing solution of sulfamide (27.25 g, 283 mmol) in anhydrous pyridine (300 ml) was added dropwise 1,2-diamino-2-methylpropane (25 g, 283 mmol) over 2 hours. The resulting mixture was refluxed for further 16 hours under nitrogen before the solvent was removed under vacuum. The residue was triturated with hexane and the solid was collected by filtration and purified by flash chromatography (silica gel, dichloromethane-methanol 96:4) to give 36.1 g (85%) of the title compound as a white solid; mp 80°-83° C.; δH (360 MHz, DMSO-d6) 7.08 (1H, br t, --NH--), 6.77 (1H, s, --NH--), 3.04 (2H, d, J=6.9 Hz, --CH2 --), 1.24 (6H, s, --CMe2); m/z (EI) 151 (M+ +1). The resulting mixture was refluxed for further 16 hours under nitrogen before the solvent was removed under vacuum The residue was triturated with hexane the solid was collected by filtration purified by flash chromatography (silica gel, dichloromethane-methanol 96:4)