(S)-4-((2-((4-Nitrophenyl)amino)-2-oxo-1-(phenylmethyl)ethyl)amino)-4-oxobutyric acid 2440-62-2 Butanoic acid, 4-((2-((4-nitrophenyl)amino)-2-oxo-1-(phenylmethyl)ethyl)amino)-4-oxo-, (S)- EINECS 219-472-6 Suphepa