2-[cyclopentyl-(2-sulfanylbenzoyl)amino]acetic acid
2-[cyclopentyl-[(2-mercaptophenyl)-oxomethyl]amino]acetic acid
2-[cyclopentyl-(2-mercaptobenzoyl)amino]acetic acid
2-[cyclopentyl-(2-sulfanylphenyl)carbonyl-amino]ethanoic acid