1: 64 percent / diethylaminosulfur trifluoride, 4-(dimethylamino)-pyridine / CH2Cl2 / 1) -20 deg C, 15 min, 2) RT, 24 h 2: H2O, EtOH, Dowex 50W-X8<H(1+)> / 4.5 h / Ambient temperature View Scheme

ethanol; Dowex 50W-X8lt;H(1+)gt;; water 4.5 h; Ambient temperature; Title compound not separated from byproducts;