Carnosine, Constitution and Synthesis

WHILE engaged on work relating to tbe physiological behaviour of the trinitrotoluenes we observed that the ,B-and y-isomerides condense with amino-acids on boiling in dilute alcoholic solution; the amino-acid becomes attached to the benzene ring by its amino-group, in replacement of a reactive nitro-group, which is eliminated.This reaction does not occur with imino- groups, whether present in a glyoxaline ring or in peptides, but does take place with the free amino-groups of peptides.The resulting compounds which are therefore N-dinitrotolylamino-acids resist boiling with concen- trated hydrochloric acid and hence this reaction provides a suitable means of determining the constitution of peptides, for it is only necessary to combine