(1S)-1-(Hydroxymethyl)-3-methylbutylamine was made from (L)-leucine methyl ester as described in Method B1b. The 2-hydroxyethylamine was converted to (2S)-4-methyl-2-(isobutylamino)pentan-1-ol as described in Method B4c. The resulting 2-hydroxyethylamine was converted to N-(1S)-1-(chloromethyl)-3-methylbutyl)-N-(isobutyl)ammonium chloride according to Method B7c. 2-Methyl-4-nitrophenyl isothiocyanate was reacted with N-(1S)-1-(chloromethyl)-3-methylbutyl)-N-(isobutyl)ammonium chloride to Method C1b to afford (4S)-2-(2-methyl-4-nitrophenylimino)-3,4-diisobutyl-1,3-thiazolidine.
