{(R)-1-[(1S,2S)-1-Cyclohexylmethyl-2-hydroxy-4-(thiazol-2-ylsulfanyl)-butylcarbamoyl]-2-methylsulfanyl-ethyl}-carbamic acid tert-butyl ester

{(R)-1-[(1S,2R)-1-Cyclohexylmethyl-2-hydroxy-3-(1H-[1,2,4]triazol-3-ylsulfanyl)-propylcarbamoyl]-2-methylsulfanyl-ethyl}-carbamic acid tert-butyl ester

{(R)-1-[(1S,2S)-1-Cyclohexylmethyl-2-hydroxy-4-(5-methyl-[1,3,4]thiadiazol-2-ylsulfanyl)-butylcarbamoyl]-2-methylsulfanyl-ethyl}-carbamic acid tert-butyl ester

{(R)-1-[(1S,2S)-1-Cyclohexylmethyl-2-hydroxy-4-(1-methyl-1H-tetrazol-5-ylsulfanyl)-butylcarbamoyl]-2-methylsulfanyl-ethyl}-carbamic acid tert-butyl ester

{(R)-1-[(1S,2S)-1-Cyclohexylmethyl-2-hydroxy-4-(5-hydroxymethyl-1-methyl-1H-imidazol-2-ylsulfanyl)-butylcarbamoyl]-2-methylsulfanyl-ethyl}-carbamic acid tert-butyl ester