1: Lawesson's reagent / toluene / 2 h / Heating 2: 78 percent / tetrabutylammonium fluoride; acetic acid / tetrahydrofuran / 20 h / 20 °C 3: 80 percent / 1,1,3,3-tetramethylguanidine; syn-o-nitrobenzaldoxime / acetonitrile / 3 h / 20 °C View Scheme