hydrogen bromide; acetic acid in tetrahydrofuran; diethyl ether T=0°C; 0.5 h;

1: (S)-2-benzyloxycarbonylamino-succinic acid 4-tert-butyl ester With 4-methyl-morpholine; isobutyl chloroformate in tetrahydrofuran T=-15°C; 0.333333 h; 2: diazomethane in tetrahydrofuran; diethyl ether T=0°C; 0.5 h; 3: With hydrogen bromide; acetic acid in tetrahydrofuran; diethyl ether T=0°C; 0.5 - 1 h;

Yield given. Multistep reaction;

1: (S)-2-benzyloxycarbonylamino-succinic acid 4-tert-butyl ester With 4-methyl-morpholine; isobutyl chloroformate in tetrahydrofuran T=0°C; 0.416667 h; 2: N-methyl-N'-nitro-N-nitroso-guanidine With potassium hydroxide in tetrahydrofuran; diethyl ether; water T=0°C; 0.25 h; 3: With hydrogen bromide in tetrahydrofuran; diethyl ether; water 0.333333 h;

1: 2,6-bis-trifluoromethyl-benzoic acid 3-[2-(11-tert-butoxycarbonylamino-10-methyl-undecanoylamino)-3-phenyl-propionylamino]-2-oxo-propyl ester With hydrogenchloride in 1,4-dioxane; methanol; water T=20°C; 0.5 h; 2: (5)-carboxy-TAMRA-NHS With N-ethyl-N,N-diisopropylamine in DMF (N,N-dimethyl-formamide) T=20°C; 2 h;

1: in diethyl ether T=0 - 20°C; 0.75 h; 2: With hydrogen bromide in water; acetic acid T=0 - 20°C; 0.5 h;

4-methyl-morpholine; hydrogen bromide; acetic acid in tetrahydrofuran; diethyl ether

1.1: ClCO2iBu; NMM / tetrahydrofuran / 0.33 h / -10 °C 1.2: diethyl ether / 0.25 h / 0 °C 2.1: aq. HBr / tetrahydrofuran / 0.5 h / 0 °C View Scheme