(R)—N-(2-Cyano-1,1-bis(3-(trifluoromethoxy)phenyl)ethyl)-2-methylpropane-2-sulfinamide (140 mg, 0.28 mmol) was stirred in EtOH (3 mL) and NH2OH in H2O (3 mL) in a capped microwave tube. The mixture was heated in an oil bath at 60-65° C. for 2 h. LC-MS (ESI) 528.42 (M+H), retention time=3.46 min (10-90% MeOH in H2O with 0.1% TFA in a 4-min run). The cap was removed and the solvents were concentrated. The residue was dissolved in CH2Cl2, washed with H2O, dried over MgSO4, filtered, and concentrated to give crude N′-hydroxy-3-(2-methylpropan-2-ylsulfinamido)-3,3-bis(3-(trifluoromethoxy)phenyl)propanamidine.
