(S)-4-sec-Butylcarbamoyl-4-{4-[methyl-(2,2,2-trifluoro-acetyl)-amino]-benzoylamino}-butyric acid tert-butyl ester

N-(p-methylaminobenzoyl)-L-glutam-α-ethylamide t-butyl ester

(S)-2-{4-[(2,4-Diamino-pteridin-6-ylmethyl)-methyl-amino]-benzoylamino}-5-oxo-5-piperidin-1-yl-pentanoic acid tert-butyl ester

(S)-4-{4-[(2,4-Diamino-pteridin-6-ylmethyl)-methyl-amino]-benzoylamino}-4-methylcarbamoyl-butyric acid

(S)-4-Isopropylcarbamoyl-4-(4-methylamino-benzoylamino)-butyric acid tert-butyl ester