methyl (4R,4'S,4''S)-4,4',4''-trimethyl-2''-((S)-4-methyl-2-oxothiazolidin-4-yl)-4,4',4'',5,5',5''-hexahydro-[2,4':2',4''-terthiazole]-4-carboxylate

methyl (R)-2-((S)-3-(tert-butoxycarbonyl)-4-methyl-2-oxothiazolidin-4-yl)-4-methyl-4,5-dihydrothiazole-4-carboxylate

(R)-4-methyl-2-((S)-4-methyl-2-oxothiazolidin-4-yl)-4,5-dihydrothiazole-4-carboxylic acid

methyl (R)-2-((S)-2-((tert-butoxycarbonyl)amino)-1-mercaptopropan-2-yl)-4-methyl-4,5-dihydrothiazole-4-carboxylate

methyl (R)-2-((S)-2-((tert-butoxycarbonyl)amino)-1-(((S)-4-methyl-2-((S)-4-methyl-2-oxothiazolidin-4-yl)-4,5-dihydrothiazole-4-carbonyl)thio)propan-2-yl)-4-methyl-4,5-dihydrothiazole-4-carboxylate