1: oxalic acid dimethyl ester With sodium hydride in tetrahydrofuran; mineral oil Hinsberg reaction; Inert atmosphereReflux; 2: HN(CH2COOMe)2 in tetrahydrofuran; mineral oil Hinsberg reaction; Inert atmosphereReflux;

sodium methylate

potassium carbonate in acetone 3.5 h; Heating;

1: 2 percent / K2CO3 / acetone / 3.5 h / Heating 2: 86 percent / K2CO3 / dimethylformamide / 8 h / 130 °C 3: 73 percent / CF3COOH/H2SO4, methoxybenzene / 0.5 h / 90 °C 4: 87 percent / 2N NaOH / H2O / 4 h / 65 °C View Scheme