The alkylation of N-acetyl-L-cysteine (I) with dodecyl bromide (II) by means of ammonia in methanol gives N-acetyl-S-dodecyl-L-cysteine (III), which is treated with isobutyl chloroformate and N-methylmorpholine (NMM) in THF yielding the mixed anhydride (IV). The reaction of (IV) with diazomethane in ethyl ether affords the diazoketone (V), which is finally treated with HCl in ethyl acetate.

The alkylation of N-acetyl-L-cysteine (I) with farnesyl bromide (II) in methanolic ammonia provided the corresponding farnesyl thioether (III). After activation of the S-alkylated acid (III) as the mixed anhydride (IV) using isobutyl chloroformate and N-methylmorpholine, reaction with diazomethane yielded the diazomethyl ketone (V). This was then converted into the title chloromethyl ketone by treatment with HCl in ethyl acetate.