(2R,3R,Z)-1-(tert-butoxycarbonyl)-4-ethylidene-3-methylpyrrolidine-2-carboxylic acid

(S)-2-{(2R,3S,Z)-1-[(S)-2-benzamido-6-guanidinohexanoyl]-4-ethylidene-3-methylpyrrolidine-2-carboxamido}-4-methyl-pentanoic acid

(2R,3S,Z)-1-(tert-butoxycarbonyl)-4-ethylidene-3-methylpyrrolidine-2-carboxylic acid

(2R,3S,Z)-tert-butyl 4-ethylidene-2-((S)-1-methoxy-4-methyl-1-oxopentan-2-ylcarbamoyl)-3-methylpyrrolidine-1-carboxylate

(2R,3R,Z)-tert-butyl 4-ethylidene-2-((S)-1-methoxy-4-methyl-1-oxopentan-2-ylcarbamoyl)-3-methylpyrrolidine-1-carboxylate