A solution of 18.6 g ethyl 3-t-butylthio-2-oxopropanoate, 26.3 g 1-(4-chlorobenzyl)-1-(4-allyloxyphenyl)hydrazine hydrochloride and 15 g NaOAc in 300 mL toluene and 150 mL HOAc was stirred at room temperature under nitrogen for 16 hours then at 70° C. for 2 hour. The mixture was cooled, poured onto H2O, extracted (3×) EtOAc and the organic layers then washed successively with sat. NaHCO3 and brine. After drying over MgSO4 the solution was filtered, evaporated and the residue chromatographed (silica gel; hexane/EtOAc 4:1) to afford the title compound.
