benzyl ((S)-1-(((3R,4S)-4-((1S,2S)-2-((2R,3S)-3-((S)-sec-butyl)-4-oxooxetane-2-carboxamido)cyclopropyl)-1-phenylpentan-3-yl)amino)-1-oxopropan-2-yl)carbamate

(3S,4R)-3-((S)-sec-butyl)-4-oxooxetane-2-carboxylic acid