In a 250 mL round bottom flask, NH 4 SCN (5 g, 65.7 mmol) was dissolved in 5 mLH 2 O and cooled to 0 • C in an ice bath. A H 2 SO 4 solution (ca. 7 mL of H 2 SO 4 in 12 mL H 2 O) was then added dropwise to the cooled NH 4 SCN solution. The reaction mixture was stirred for 30 mins before being warmed to room temperature. The aqueous mixture was subsequently extracted with diethyl ether (2×20 mL) and the organic phase was retrieved and its volume reduced by half using a stream of N 2 .