... (1S,2S,3S,4R)-3-[(1S)-1-acetamido-2-ethylbutyl]-4-(diaminomethylideneamino)-2-hydroxycyclopentane-1-carboxylic acid.3. Properties : Peramivir Purity ... (1S,2S,3S,4R)-3-[(1S)-1-Acetamido-2-ethylbutyl]-4-[(diaminomethylene)amino]-2-hydroxycyclopentanecarboxylic acid