acetic acid in 1,4-dioxane T=20°C;

formaldehyd in ethanol; chloroform

1: 1-Diethoxymethylindole-5-carbonitrile With Merrifield resin bound glycerol; toluene-4-sulfonic acid in 1,4-dioxane T=20°C; Solid phase reaction; Transacetalization; 3 h; 2: N,N-dimethyl(methylene)ammonium chloride in N,N-dimethyl-formamide T=20°C; Solid phase reaction; Substitution; 48 h; 3: With hydrogenchloride; water in 1,4-dioxane T=40°C; Solid phase reaction; Hydrolysis; 3 h;

1.1: 91 percent / 24 h / 160 °C 2.1: Merrifield resin bound glycerol; TsOH / dioxane / 3 h / 20 °C 2.2: dimethylformamide / 48 h / 20 °C 2.3: HCl; H2O / dioxane / 3 h / 40 °C View Scheme