1: N-(pyrazine-2-yl-carbonyl)-L-phenylalanine sodium salt With O-(benzotriazol-1-yl)-N,N,N',N'-tetramethyluronium tetrafluoroborate in dichloromethane T=0°C; 0.5 h; 2: (1R)-3-methyl-1-[(3aS,4S,6S,7aR)-3a,5,5-trimethythexahydro-4,6-methano-1,3,2-benzodioxa-borol-2-yl]butan-1-amine trifluoroacetate in dichloromethane T=0 - 25°C; 24 h;

4-methyl-morpholine; 1-propanephosphonic acid cyclic anhydride in dichloromethane; acetonitrile T=-15 - 25°C; 1.5 h;

1: With O-(benzotriazol-1-yl)-N,N,N',N'-tetramethyluronium tetrafluoroborate in toluene 0.166667 h; Inert atmosphere; 2: With N-ethyl-N,N-diisopropylamine in toluene T=25°C; 3 h; Concentration;

1: (S)-3-phenyl-2-(pyrazine-2-carboxamido) propanoic acid With benzotriazol-1-ol in dichloromethane T=-5°C; 0.333333 h; 2: (1R)-3-methyl-1-[(3aS,4S,6S,7aR)-3a,5,5-trimethylhexahydro-4,6-methano-1,3,2-benzodioxabor-ol-2-yl]butan-1-amine hydrochloride With 1-ethyl-(3-(3-dimethylamino)propyl)-carbodiimide hydrochloride; N-ethyl-N,N-diisopropylamine in dichloromethane T=-15 - 20°C; 3 h;

O-(benzotriazol-1-yl)-N,N,N',N'-tetramethyluronium tetrafluoroborate; N-ethyl-N,N-diisopropylamine in dichloromethane T=-1.2 - 24.9°C; 2.18333 h; Industry scale;

N-ethyl-N,N-diisopropylamine; HATU in N,N-dimethyl-formamide T=0 - 20°C; Inert atmosphere;

1: benzotriazol-1-ol; 1-ethyl-(3-(3-dimethylamino)propyl)-carbodiimide hydrochloride; N-ethyl-N,N-diisopropylamine / N,N-dimethyl-formamide / 0 - 20 °C / Inert atmosphere 2: lithium hydroxide hydrate / tetrahydrofuran; water / 3 h / 0 °C 3: N-ethyl-N,N-diisopropylamine; HATU / N,N-dimethyl-formamide / 0 - 20 °C / Inert atmosphere View Scheme

1: N-ethyl-N,N-diisopropylamine; HATU / N,N-dimethyl-formamide / 0 - 20 °C / Inert atmosphere 2: hydrogenchloride / tetrahydrofuran; water / 3 h 3: N-ethyl-N,N-diisopropylamine; HATU / N,N-dimethyl-formamide / 0 - 20 °C / Inert atmosphere View Scheme

1: N-ethyl-N,N-diisopropylamine; HATU / N,N-dimethyl-formamide / 0 - 20 °C / Inert atmosphere 2: palladium 10 on activated carbon; hydrogen / ethanol; triethylamine / 3102.97 Torr 3: N-ethyl-N,N-diisopropylamine; HATU / N,N-dimethyl-formamide / 0 - 20 °C / Inert atmosphere View Scheme

1: hydrogenchloride / tetrahydrofuran; water / 3 h 2: N-ethyl-N,N-diisopropylamine; HATU / N,N-dimethyl-formamide / 0 - 20 °C / Inert atmosphere View Scheme