H-ALA-ALA-PHE-PNA

(6R,7R)-3-((((S)-2-((S)-2-aminopropanamido)propanoyl)oxy)methyl)-8-oxo-7-(2-(thiophen-2-yl)acetamido)-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid

N-(N-benzyloxycarbonyl-alanyl)-alanine benzyl ester