(R)-((2R)-4t-carboxy-5,5-dimethyl-thiazolidin-2r-yl)-(2-phenoxy-acetylamino)-acetic acid

(4S)-2t-((R)-amino-tert-butoxycarbonyl-methyl)-5,5-dimethyl-thiazolidine-4r-carboxylic acid

(4S)-2t-[(R)-tert-butoxycarbonyl-(2-phenoxy-acetylamino)-methyl]-5,5-dimethyl-thiazolidine-4r-carboxylic acid

(4S)-2t-((R)-tert-butoxycarbonyl-phthalimido-methyl)-5,5-dimethyl-thiazolidine-4r-carboxylic acid

2-[1-(1,3-dioxoisoindol-2-yl)-2-[(2-methylpropan-2-yl)oxy]-2-oxoethyl]-5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid