To a cooled (0° C.) solution of 2-{4-[5-(5-diethylaminomethyl-4-methyl-thiophen-2-yl)-[1,2,4]oxadiazol-3-yl]-phenyl}-ethanol (196 mg, 488 μmol) and DIPEA (84 mg, 732 μmol) in THF (5 mL), methanesulfonyl chloride (126 mg, 976 μmol) is added as a solution in THF (2.5 mL). The reaction mixture is stirred at 0° C. for 1 h, then at rt for 1 h. The mixture is diluted with DCM (100 mL) and washed with brine (3×50 mL). The organic extract is dried over MgSO4, filtered, concentrated and dried to give crude methanesulfonic acid 2-{4-[5-(5-diethylaminomethyl-4-methyl-thiophen-2-yl)-[1,2,4]oxadiazol-3-yl]-phenyl}-ethyl ester (295 mg); LC-MS: tR=0.59 min; [M+1]+=449.71. b) A solution of methanesulfonic acid 2-{4-[5-(5-diethylaminomethyl-4-methyl-thiophen-2-yl)-[1,2,4]oxadiazol-3-yl]-phenyl}-ethyl ester (295 mg, 658 μmol) in 7 N NH3 in methanol (10 mL) is stirred in a sealed vessel at 80° C. for 16 h. The reaction mixture is concentrated and dried to give the title compound (255 mg) as a pale yellow oil; LC-MS: tR=0.64 min; [M+1]+=370.97.
