20898-44-6 Histidine, 1-benzyl-N-carboxy-, N-tert-butyl ester, L- L-Histidine, N-[(1,1-dimethylethoxy)carbonyl]-1-(phenylmethyl)- N-[(1,1-Dimethylethoxy)carbonyl]-1-phenylmethyl-L-histidine NSC164043