A solution of 1,1-dimethylethyl (3S)-3-((1-methylethyl)-{[2-(trifluoromethyl)-5-fluorophenyl]-methyl}amino)-pyrrolidine-1-carboxylate (0.26 g) in a mixture of trifluoroacetic acid (2 mL), dichloromethane (8 mL) and water (0.2 mL) was stirred at room temperature for 3 hours. The reaction mixture was evaporated in vacuo. The crude mixture was taken up in methanol and absorbed onto an SCX-2 ion exchange cartridge. After initially washing with methanol, the product was eluted with 2M methanolic ammonia and the collected fractions evaporated in vacuo. The crude product was taken up in methanol and fumaric acid (1 equiv. ) in methanol added. The solvent was removed in vacuo and the resultant gum triturated with diethyl ether. The solid formed was filtered off and dried in vacuo at 50° C. to yield the title compound as an off-white microcrystalline solid. 1H NMR (300 MHz, CD3OD) δH: 1.09 (d, 3H), 1.10 (d, 3H), 1.87 (m, 1H), 2.15 (m, 1H), 3.01 (m, 2H), 3.23 (m, 1H), 3.38 (m, 2H), 3.81 (m, 1H), 3.91 (s, 2H), 6.70 (s, 2H), 7.15 (dt, 1H), 7.73 (m, 2H); MS: [M+H]=305.
