Six analogues of thyroliberin (TRH) that have a chloroacetyl substituent at the amino terminus have been prepared as potential affinity labels for the TRH receptor. These compounds are N-(chloroacety1)-L-alanyl-L-phenyl-alanylpyrrolidine (ClAoAla-PhePyrr; 141, N-[m-(ehloroacetyl) bemyl]-bphenylalanylpyr~~ lidine (m-CMdbPhe-Pyrr; 1 la), N-[m- (chloroacetyl) benzoy1]-~-alanyl-~-pheny~ ylpyrrolidine (m-ClAcBz-Ala-Phe-Pyrr; 15a), N- ...
