1: ethyl bromoacetate; acetonitrile With methanesulfonic acid; zinc in tetrahydrofuran Blaise reaction; Reflux; 2: acetic anhydride With n-butyllithium in tetrahydrofuran; cyclohexane 0 - 20 h; chemoselective reaction;

toluene-4-sulfonic acid in ethanol T=20°C; 2 h; Reflux; regioselective reaction;