trans-cyclo(Val-D-Phe)

(S)-2-(4-nitrobenzenesulfonylamino)-3-methyl-butyric acid methyl ester

(2R,5S)-5-isopropyl-3,6-dimethoxy-2-methyl-2-(prop-2-yn-1-yl)-2,5-dihydropyrazine

(3S,6S)-3-isopropyl-6-(cyclohexylmethyl)piperazine-2,5-dione