1: With Ba(OH)2·8H2O; water in ethanol Inert atmosphereReflux; 2: With hydrogenchloride in water T=18 - 25°C; pH=1 - 2;

barium dihydroxide in methanol; water 18 h; Ambient temperature;

1.1: diisopropylamine; n-butyllithium / hexane; N,N'-dimethyl-N,N'-propyleneurea; tetrahydrofuran / 1 h / -78 °C / Inert atmosphere 1.2: -78 - 25 °C 2.1: diisopropylamine; n-butyllithium / hexane; N,N'-dimethyl-N,N'-propyleneurea; tetrahydrofuran / -78 - 25 °C / Inert atmosphere 3.1: water; Ba(OH)2·8H2O / ethanol / Inert atmosphere; Reflux 3.2: 18 - 25 °C / pH 1 - 2 View Scheme

1.1: chloro-trimethyl-silane / 96 h / 18 - 25 °C / Inert atmosphere 2.1: diisopropylamine; n-butyllithium / hexane; N,N'-dimethyl-N,N'-propyleneurea; tetrahydrofuran / 1 h / -78 °C / Inert atmosphere 2.2: -78 - 25 °C 3.1: diisopropylamine; n-butyllithium / hexane; N,N'-dimethyl-N,N'-propyleneurea; tetrahydrofuran / -78 - 25 °C / Inert atmosphere 4.1: water; Ba(OH)2·8H2O / ethanol / Inert atmosphere; Reflux 4.2: 18 - 25 °C / pH 1 - 2 View Scheme

1.1: diisopropylamine; n-butyllithium / hexane; N,N'-dimethyl-N,N'-propyleneurea; tetrahydrofuran / -78 - 25 °C / Inert atmosphere 2.1: water; Ba(OH)2·8H2O / ethanol / Inert atmosphere; Reflux 2.2: 18 - 25 °C / pH 1 - 2 View Scheme