Aw. Erian, beta-enaminoesters as building blocks in heterocyclic synthesis. A novel synthesis of fused azines by using Blaise reaction as a key step, J PRAK CH C, 341(2), 1999, pp. 147-151
Ethyl bromoacetate 4 reacts with nitriles in the presence of activated zinc
dust to afford the beta-enaminoesters 7 and 19. Compounds 7 and 19 show hi
gh reactivity towards a variety of reagents to give polyfunctional heterocy
clic compounds. For example. the enaminoesters 7 and 19 react with benzalde
hyde to give the 1,4 dihydropyridine derivatives 9 and 20, respectively. Is
othiocyanates 24 (R = Ph, Oft) added to 19 to furnish pyrimidine-thiones 26
and 27 respectively. Structures and conceivable mechanisms are discussed.