Synthesis and subsequent reactivity of 1-amino-2-aza-1,3-butadienes derived from β-amino esters

A high yield preparation of 1-amino-2-aza-1,3-butadienes derived from β-amino esters from N-unsubstituted amidines and acetylenic esters is described. These substrates are efficient starting material for the preparation of dihydrotriazines and 5-amino pyrrolidin-3-ones.