1: mercaptoacetic acid With lithium hydroxide hydrate in ethanol T=25°C; 0.75 h; 2: (6S)-N-(2-amino-4,5,6,7-tetrahydrobenzothiazole-6-yl)-2-nitro-N-propylbenzenesulfonamide in ethanol T=50°C; 4 h; Inert atmosphere;

1.1: water; sulfuric acid / 10 h / Reflux 1.2: 1.5 h / 0 - 30 °C 2.1: water / 70 °C / Reflux; Resolution of racemate 3.1: hydrogenchloride / water / carbon treatment 3.2: 1.5 h / 25 - 30 °C 4.1: triethylamine / methanol / 1.5 h / 10 - 20 °C 5.1: sodium tetrahydroborate; boron trifluoride diethyl etherate / tetrahydrofuran / 4 h / 0 - 50 °C 5.2: 0.17 h / 10 °C View Scheme

1.1: bromine; acetic acid / 0.75 h / 25 - 35 °C 1.2: 3 h / Reflux 2.1: water; sulfuric acid / 10 h / Reflux 2.2: 1.5 h / 0 - 30 °C 3.1: water / 70 °C / Reflux; Resolution of racemate 4.1: hydrogenchloride / water / carbon treatment 4.2: 1.5 h / 25 - 30 °C 5.1: triethylamine / methanol / 1.5 h / 10 - 20 °C 6.1: sodium tetrahydroborate; boron trifluoride diethyl etherate / tetrahydrofuran / 4 h / 0 - 50 °C 6.2: 0.17 h / 10 °C View Scheme

1.1: hydrogenchloride / water / carbon treatment 1.2: 1.5 h / 25 - 30 °C 2.1: triethylamine / methanol / 1.5 h / 10 - 20 °C 3.1: sodium tetrahydroborate; boron trifluoride diethyl etherate / tetrahydrofuran / 4 h / 0 - 50 °C 3.2: 0.17 h / 10 °C View Scheme

oxygen; rose bengal 1 h; Irradiation;

hydrogenchloride in water; acetone T=0 - 3°C; pH=1.5; 2 h; Product distribution / selectivity;