sodium sulfide in N,N-dimethyl-formamide 2 h; Heating;

1: 1.) <Pd(PPh3)2>Cl2, CuI, Et3N / 1.) DMSO, THF, 30 min, 2.) 6 h 2: 71 percent / NaOH / toluene / 2 h / Heating 3: 64 percent / Na2S*9H2O / dimethylformamide / 2 h / Heating View Scheme

1: 71 percent / NaOH / toluene / 2 h / Heating 2: 64 percent / Na2S*9H2O / dimethylformamide / 2 h / Heating View Scheme

iron (II) oxalate