(3S)-2-[(S)-2-[[(S)-1-Carboxy-3-phenylpropyl]amino]propionyl]-2-aza-6,9-dithiaspiro[4.4]nonane-3-carboxylic acid

(8S)-7-[(2S)-2-[[(1S)-1-Carboxy-3-phenylpropyl]amino]-1-oxopropyl]-1,4-dithia-7-azaspiro[4.4]nonane-8-carboxylic acid

1,4-Dithia-7-azaspiro(4.4)nonane-8-carboxylic acid, 7-(2-((1-carboxy-3-phenylpropyl)amino)-1-oxopropyl)-, (8S-(7(R*(R*)),8R*))-