hydrogenchloride in water Mannich Reaction; 5 h; Heating / reflux;

sodium hydroxide; water pH=10.0 - 10.5;

trifluoroacetic acid Mannich Reaction;

trifluoroacetic acid Mannich Reaction;

1: acetone; methanol 2: diethylamine / tert-butyl methyl ether View Scheme

1.1: acetone; methanol 2.1: diethylamine / tert-butyl methyl ether 3.1: diethyl ether; tetrahydrofuran / 2 h / 10 - 15 °C 3.2: 5 °C 4.1: hydrogenchloride / water / 5 h / 55 °C 4.2: 20 °C / pH 12 5.1: hydrogenchloride; hydrogen / palladium 10 on activated carbon / ethanol; water / 20 °C / Inert atmosphere View Scheme

1.1: acetone; methanol 2.1: diethylamine / tert-butyl methyl ether 3.1: diethyl ether; tetrahydrofuran / 2 h / 10 - 15 °C 3.2: 5 °C 4.1: hydrogenchloride / water / 5 h / 55 °C 4.2: 20 °C / pH 12 5.1: hydrogenchloride; hydrogen / palladium 10 on activated carbon / ethanol; water / 20 °C / Inert atmosphere 6.1: methanesulfonic acid; dl-methionine / 72 h / 80 °C 6.2: pH 10 - 12 View Scheme

in acetone T=35 - 40°C; 27 h; Resolution of racemate; Purification / work up;