1: acetonitrile With n-butyllithium in tetrahydrofuran; hexanes T=-78°C; 1.5 h; 2: 2-(dimethylamino-methyleneamino)-5-methoxy-4-(2-methoxy-ethoxy)-benzoic acid methyl ester in tetrahydrofuran; hexanes T=-78 - -55°C; 1 h; 3: With acetic acid in tetrahydrofuran; hexanes T=-55 - 20°C;

n-butyllithium; acetic acid; acetonitrile in tetrahydrofuran; hexane T=-78 - 20°C; 1.5 h;