4′-(N-(Propargyl)pyrrol-2-yl)-2,2′:6′,2′′-terpyridine

Abstract

A new terpyridine molecule, bearing a N-propargylated pyrrole, was prepared and characterized. Its synthesis was based on a Krohnke-type reaction between 2-acetylpyridine and N-propargylpyrrole-2-carboxaldehyde in a basic medium. An allene-containing terpyridine was also obtained as a by-product.

4′-(3,5-Dimethoxy-4-propargyloxyphenyl)-2,2′:6′,2″-terpyridine

“…Only a single product was observed by TLC and NMR (vide infra). No isomerization of the triple bond to an allene occurred, in contrast to what has been reported for the preparation of another terminal alkyne-containing terpyridine, namely 4 -(N-(propargyl)pyrrol-2-yl)-2,2 :6 ,2 -terpyridine, using the same protocol [31].…”

4′-(N-(2-Cyanoethyl)pyrrol-2-yl)-2,2′:6′,2″-terpyridine

“…Nevertheless, these synthetic pathways require basic media, which can result in sidereactions with certain substrates, as already reported in the literature [8,9]. Consequently, other synthetic protocols must be envisioned for the preparation of such terpyridinepyrrole compounds.…”