1-ethyl-(3-(3-dimethylamino)propyl)-carbodiimide hydrochloride; N-ethyl-N,N-diisopropylamine in dichloromethane T=20°C; 4 h;

1.1: hydroxylamine hydrochloride; sodium hydroxide / ethanol / 4.5 h / 20 °C / pH 5 / Reflux 2.1: N-chloro-succinimide / N,N-dimethyl-formamide / 0 - 20 °C 3.1: acetonitrile / 2 h / 0 °C 4.1: SnCl2·2H2O / ethanol / 1.5 h / Reflux 4.2: pH 8 5.1: trifluoroacetic acid / 1 h / 20 °C 6.1: N-ethyl-N,N-diisopropylamine; 1-ethyl-(3-(3-dimethylamino)propyl)-carbodiimide hydrochloride / dichloromethane / 4 h / 20 °C View Scheme

1.1: N-chloro-succinimide / N,N-dimethyl-formamide / 0 - 20 °C 2.1: acetonitrile / 2 h / 0 °C 3.1: SnCl2·2H2O / ethanol / 1.5 h / Reflux 3.2: pH 8 4.1: trifluoroacetic acid / 1 h / 20 °C 5.1: N-ethyl-N,N-diisopropylamine; 1-ethyl-(3-(3-dimethylamino)propyl)-carbodiimide hydrochloride / dichloromethane / 4 h / 20 °C View Scheme

1.1: acetonitrile / 2 h / 0 °C 2.1: SnCl2·2H2O / ethanol / 1.5 h / Reflux 2.2: pH 8 3.1: trifluoroacetic acid / 1 h / 20 °C 4.1: N-ethyl-N,N-diisopropylamine; 1-ethyl-(3-(3-dimethylamino)propyl)-carbodiimide hydrochloride / dichloromethane / 4 h / 20 °C View Scheme

1.1: SnCl2·2H2O / ethanol / 1.5 h / Reflux 1.2: pH 8 2.1: trifluoroacetic acid / 1 h / 20 °C 3.1: N-ethyl-N,N-diisopropylamine; 1-ethyl-(3-(3-dimethylamino)propyl)-carbodiimide hydrochloride / dichloromethane / 4 h / 20 °C View Scheme

1: N,N-dimethyl-formamide / 20 - 100 °C 2: N-ethyl-N,N-diisopropylamine; 1-ethyl-(3-(3-dimethylamino)propyl)-carbodiimide hydrochloride / dichloromethane / 4 h / 20 °C View Scheme

1: trifluoroacetic acid / 1 h / 20 °C 2: N-ethyl-N,N-diisopropylamine; 1-ethyl-(3-(3-dimethylamino)propyl)-carbodiimide hydrochloride / dichloromethane / 4 h / 20 °C View Scheme