(3S)-3-{[(1RS,3SR)-3-({[(9H-fluoren-9-yl)methoxy]carbonyl}amino)cyclopentyl]formamido}-4-methylpentanoic acid

2-({2-[4-({[(9H-fluoren-9-yl)methoxy]carbonyl}amino)-1H-pyrazol-1-yl]acetamido}oxy)-3-methoxypropanoic acid

2-{[2-({[(9H-fluoren-9-yl)methoxy]carbonyl}amino)-2-methylbutanamido]oxy}-3-methoxypropanoic acid

2-{[(3R)-3-({[(9H-fluoren-9-yl)methoxy]carbonyl}amino)butanamido]methyl}butanoic acid

3-[(3R)-3-({[(9H-fluoren-9-yl)methoxy]carbonyl}amino)butanamido]bicyclo[2.2.1]heptane-2-carboxylic acid

4-[3-(dimethylamino)-2-({[(9H-fluoren-9-yl)methoxy]carbonyl}amino)propanamido]-3-hydroxybutanoic acid

1-[3-(dimethylamino)-2-({[(9H-fluoren-9-yl)methoxy]carbonyl}amino)propanoyl]-4-methylpyrrolidine-3-carboxylic acid

3-[3-(dimethylamino)-N-ethyl-2-({[(9H-fluoren-9-yl)methoxy]carbonyl}amino)propanamido]butanoic acid

1-{3-[benzyl(methyl)amino]-2-({[(9H-fluoren-9-yl)methoxy]carbonyl}amino)propanoyl}-2-methylpiperidine-2-carboxylic acid

3-(1-{3-[benzyl(methyl)amino]-2-({[(9H-fluoren-9-yl)methoxy]carbonyl}amino)propanoyl}pyrrolidin-3-yl)propanoic acid

4-{5-[({[(9H-fluoren-9-yl)methoxy]carbonyl}amino)methyl]-1,2-oxazole-3-carbonyl}thiomorpholine-3-carboxylic acid