1: With sodium 3-methoxy-3-oxopropane-1-sulfinate in dimethyl sulfoxide T=20°C; 2: With sodium methylate in methanol; dimethyl sulfoxide T=20°C; 0.25 h; 3: With sodium acetate; hydroxylamine-o-sulphonic acid in water T=20°C; 20 h;

sulfuric acid T=65°C; 24 h; Yield given;