NH2NHCONH2 being more nucleophilic attack at the electrophilic carbonyl carbon of ethyl acetate group. Thus, ethyl acetate reacts with NH2NHCONH2 to form CH3CONHNHCONH2, which is a peptide linkage. CH3O∣∣COC2H5+H2NNHO∣∣CNH2→CH3−O∣∣C−NHNHO∣∣C−NH2