2-[[4-(phenylazo)benzyl]sulphonyl]ethyl S-(acetamidomethyl)-N-(tert-butoxycarbonyl)-L-cysteinate

S-[(Acetylamino)methyl]-N-[(1,1-dimethylethoxy)carbonyl]-L-cysteine 2-[[[4-(phenylazo)phenyl]methyl]sulfonyl]ethyl ester