Synthesis and subsequent reactivity of 1-amino-2-aza-1,3-butadienes derived from β-amino esters
摘要:
A high yield preparation of 1-amino-2-aza-1,3-butadienes derived from beta-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. (c) 2006 Elsevier Ltd. All rights reserved.
Achiral and opticallyactive N-vinylic amidines are obtained by simple addition of amidines to acetylenic esters. Thermal intramolecular cyclization of these substrates containing a carboxylate group in position 3 gives pyrrolin-3-ones. The enaminone character of these compounds towards propargyl bromide, diethyl azodicarboxylate, diethyl acetylenedicarboxylate, ethyl propiolate and phenyl isocyanate