potassium hydroxide in ethanol; water 18 h; Heating; Yield given;

1: 1.) sodium acetate, 2.) 85percent H3PO4 / 1.) water, 20 min, 2.) RT, 1 h 2: 60 percent / Cu2Br2, Na2CO3, N-methylpyrrolidinone / 4 h / Heating 3: KOH / ethanol; H2O / 18 h / Heating View Scheme

1: 60 percent / Cu2Br2, Na2CO3, N-methylpyrrolidinone / 4 h / Heating 2: KOH / ethanol; H2O / 18 h / Heating View Scheme