1: 80 percent / P2S5 / dioxane / 1.5 h / Heating 2: 56 percent / 2 N NaOH / H2O / 72 h 3: 1) ethyl chloroformiate; 2) H2NNH2 / 1) diethylenglycol dimethyl ether, 24 h; 2) C2H5OH, 2 h, reflux View Scheme

1: 56 percent / 2 N NaOH / H2O / 72 h 2: 1) ethyl chloroformiate; 2) H2NNH2 / 1) diethylenglycol dimethyl ether, 24 h; 2) C2H5OH, 2 h, reflux View Scheme

1: 79 percent / methanol / 72 h 2: 80 percent / P2S5 / dioxane / 1.5 h / Heating 3: 56 percent / 2 N NaOH / H2O / 72 h 4: 1) ethyl chloroformiate; 2) H2NNH2 / 1) diethylenglycol dimethyl ether, 24 h; 2) C2H5OH, 2 h, reflux View Scheme

chloroformic acid ethyl ester; hydrazine 1) diethylenglycol dimethyl ether, 24 h; 2) C2H5OH, 2 h, reflux; Yield given. Multistep reaction;