1: (S)-2-[(2'-cyanobiphenyl-4-ylmethyl)amino]-3-methylbutyric acid benzyl ester hydrochloride With sodium hydrogencarbonate in water; toluene T=25°C; 1 h; 2: n-valeryl chloride With N-ethyl-N,N-diisopropylamine in water; toluene T=15 - 25°C; 0.5 - 1 h; 3: With hydrogenchloride in toluene T=0°C; pH=1 - 3; 0.5 h; Product distribution / selectivity;

N-ethyl-N,N-diisopropylamine in dichloromethane T=20°C; 20 - 25 h; Product distribution / selectivity;

sodium carbonate in dichloromethane

1.1: N-bromosuccinmide; hydrogen bromide; 2,2'-azo-bisisobutyronitrile / water; cyclohexane / 3 h / 65 - 68 °C 2.1: sodium hydroxide / water; anhydrous xylene / 20 °C / pH < 8.5 - 9 / |Large scale 2.2: 3.42 h / 60 °C / |Large scale 2.3: 2 h / 72 °C / |Dean-Stark; |Large scale 3.1: sodium hydroxide / water; anhydrous xylene / 0.5 h / 50 °C 3.2: 2 h / 40 °C View Scheme

sodium azide; tributyltin chloride; tetrabutylammomium bromide in toluene 30 h; Heating / reflux;

1.1: hydrogen / palladium 10 on activated carbon / ethanol / 1 h / 20 - 25 °C / 75.01 Torr 2.1: diethyl aluminium azide / xylene / 20 - 110 °C 2.2: 1 h / 0 °C View Scheme