methyl (4R,4'S)-4,4'-dimethyl-2'-((S)-4-methyl-2-oxothiazolidin-4-yl)-4,4',5,5'-tetrahydro-[2,4'-bithiazole]-4-carboxylate

methyl (4R,4'S)-2'-((S)-2-((tert-butoxycarbonyl)amino)-1-mercaptopropan-2-yl)-4,4'-dimethyl-4,4',5,5'-tetrahydro-[2,4'-bithiazole]-4-carboxylate