1: N-chloro-(2S,3S)-amino-3-methyl-pentanoic acid ethyl ester With sulfuric acid T=3 - 9°C; 3 h; UV-irradiation; 2: di-tert-butyl dicarbonate With potassium carbonate in 1,4-dioxane; water T=0 - 20°C; Further stages.;

sulfuric acid T=3 - 9°C; 3 h; UV-irradiation;

sodium hydroxide; sulfuric acid 1) 0 deg C, 40 h irradiation; 2) 0 deg C, pH 7-7.4, then 2 h reflux in 0.24N methanolic NaOH; Yield given. Multistep reaction;