(R)-9-methyl-6-oxo-6,7,8,9-tetrahydropyrido[3',2':4,5]pyrrolo[1,2-a]pyrazine-2-carboxylic acid

2-{[(Benzyloxy)carbonyl]amino}-4-(2-methylpropyl)thiophene-3-carboxylic acid

3-[(2S)-N-ethyl-2-({[(9H-fluoren-9-yl)methoxy]carbonyl}amino)-3-methoxypropanamido]-2-methylpropanoic acid

3-(bromomethyl)-4-cyano-5-({[(9H-fluoren-9-yl)methoxy]carbonyl}amino)thiophene-2-carboxylic acid

2-[(2-Methylpropan-2-yl)oxycarbonylamino]-4-(5-methylthiophen-2-yl)thiophene-3-carboxylic acid

2-{[(Tert-butoxy)carbonyl]amino}-4-(4-methylphenyl)thiophene-3-carboxylic acid

tert-butyl N-[2-(2-chloro-4,6-dimethylpyridin-3-yl)-1-oxopropan-2-yl]-N-methylcarbamate

3-{[(Tert-butoxy)carbonyl]amino}-4-(pyrrolidin-1-yl)benzoic acid

2-[(2R,3S)-3-(benzyloxy)-2-({[(9H-fluoren-9-yl)methoxy]carbonyl}amino)butanoyl]-2-azabicyclo[4.1.0]heptane-1-carboxylic acid

rac-(2R,4R)-1-[4-({[(9H-fluoren-9-yl)methoxy]carbonyl}amino)-3-methoxybutanoyl]-2-methylpiperidine-4-carboxylic acid

(2RS,4RS)-1-[(2S)-2-({[(9H-fluoren-9-yl)methoxy]carbonyl}amino)-4-(methylsulfanyl)butanoyl]-2-methylpiperidine-4-carboxylic acid