1542132-88-6 (2E,6S)-7-1-2-(2-Ethylbutyl)amino-2-oxoethyl-1,2-dihydro-2-oxo-3-pyridinylamino-6-(1-methyl-1H-imidazol-5-yl)carbonylamino-7-oxo-2-heptenoic Acid Methyl Ester