To the crude ethyl 4-{1-[(adamantan-1-ylcarbonyl)amino]-2-methylpropyl}benzoate in a vial was added potassium hydroxide (0.11 g, 1.87 mmol), hydroxylamine hydrochloride (0.047 g, 0.68 mmol), and methanol (2 mL). The reaction was capped and heated at 80° C. for 1 h. After cooled to rt, acetic acid (0.097 mL, 1.7 mmol was added to neutralize the excess base. The solvent was then completely evaporated. To the solid was added DMSO (1.3 mL). The solution was then filtered and purified by prep-HPLC purification to give the title compound (0.009 g, 15%) as a white solid. LC-MS: (FA) ES+ 371.
