1: With N-ethyl-N,N-diisopropylamine in 1-methyl-pyrrolidin-2-one; water T=-20 - -5°C; 2: With 4-methyl-morpholine; hydrogenchloride; 5 Pd(II)/C(eggshell); hydrogen in 1-methyl-pyrrolidin-2-one; water T=25°C; pH=6.5 - 7;

N-ethyl-N,N-diisopropylamine in acetonitrile T=-15 - -10°C; 5 - 8 h;

1: 4-Nitrobenzyl (2S,4S)-4-(acetylthio)-2-[(dimethylamino)carbonyl]pyrrolidine-1-carboxylate With pyrrolidine in N,N-dimethyl-formamide T=-5 - 0°C; 0.5 h; 2: MAP With N-ethyl-N,N-diisopropylamine in N,N-dimethyl-formamide T=-40 - -35°C; 1 h;

1: diisopropylamine / N,N-dimethyl-formamide / 3 h / -30 - -10 °C 2: 2,6-dimethylpyridine; hydrogen; 4-methyl-morpholine; palladium 10 on activated carbon / water; ethyl acetate / 0 - 10 °C / 5250.53 - 7500.75 Torr View Scheme

1: diisopropylethylamine / acetonitrile / 0.67 h / -5 °C 2: H2 / 10percent Pd / C / tetrahydrofuran; H2O / 1.67 h / 3040 Torr / Ambient temperature 3: ethyl formimidate hydrochloride, 1N NaOH / tetrahydrofuran; H2O / 0.08 h / 0 °C View Scheme

potassium phosphate buffer; hydrogen; N-ethyl-N,N-diisopropylamine; palladium on activated charcoal 1.) DMF, MeOH, 0 deg C to 5 deg C, 25 min, 2.) n-butanol, EtOAc, water, 3.2 kg/cm2, 2 h; Yield given. Multistep reaction;