(S)-2-benzyloxycarbonylaminopentanedioic acid 5-tert-butyl ester 1-ethyl ester

5-(tert-butyl)-1-ethyl-(2S)-2-{[(3,5-dimethyl-4-isoxazolyl) sulfonyl]amino}pentanedioate

ethyl 2(S)-2-{[(benzyloxy)carbonyl]amino}-5-oxo-5-[9-(4-pyridyl)-3,9-diazaspiro [5.5]undec-3-yl]pentanoate

ethyl (S,Z)-2-((butoxycarbonyl)amino)-5-(2-(4-(N'-hydroxycarbamimidoyl)phenyl)-1-oxo-2,8-diazaspiro[4.5]decan-8-yl)-5-oxopentanoate

(4S)-4-{[(3,5-dimethyl-4-isoxazolyl)sulfonyl]amino}-5-ethoxy-5-oxopentanoic acid

(4S)-4-{[(4-methylphenyl)sulfonyl]amino}-5-ethoxy-5-oxopentanoic acid

5-ethoxy-5-oxo-4-(phenylmethoxycarbonylamino)pentanoic acid

(S)-2-(n-butoxycarbonylamino)-5-[2-(4-cyanophenyl)-1-oxo-2,8-diazaspiro[4.5]dec-8-yl]-5-oxopentanoic acid ethyl ester

5-(tert-butyl) 1-ethyl (2S)-2-[(butylsulfonyl)amino]pentandioate

(S)-2-(n-butoxycarbonylamino)-5-[2-(4-carbamimidoylphenyl)-1-oxo-2,8-diazaspiro[4.5]dec-8-yl]-5-oxopentanoic acid ethyl ester

(4S)-4-[(butylsulfonyl)amino]-5-ethoxy-5-oxopentanoic acid