|
Abstract
|
Simple nitrogen-containing heterocycles receive considerable attention in the literature, because of their biological properties and their role as pharmacophores of historical importance [1]. Accordingly, many strategies have been developed for the preparation of these systems [2, 3]. Enaminons are employed in several new preparations of pyrrole derivatives. For example, the conjugated addition of a1kyl 3-aminocrotonates to (E)-l,2- dibenzoylacetylene results in the formation of polysubstituted pyrroles [4]. As part of our current studies on the development of the reaction of enaminones with dibenzoylacetylene to produced 3-alkylidene-2, 3-dihydro-1H-pyrrole-2-ol derivatives [5. 6], we wish to report an efficient rout to polysubstituted pyrroles using dibenzoylacetylene and enaminoncarbonyl compounds derived in situ from the reaction of acetylenic esters and primary amines, followed by treatment of addition product with various alchohols under acidic conditions.
|