The synthesis of new pyrrolo[1,2-a]perimidin-10-one dyes via two convenient routes and its characterizations

Efficient synthesis of pyrrolo[1,2-a]perimidin-10-ones (4, 8) are accomplished via two new convenient methods in moderate yields. The first method is the reaction of oxalyl chloride with heterocyclic ketene aminals (HKAs) containing perimidine moiety (3), and the second is the reaction of 1,8-naphthalenediamine (1) with 2-alkoxycarbonylmethylene substituted furan-3-ones (7). The visible absorption spectrums of 4 and 8 were dominated by the characteristic perimidines bands in the region 381–439 nm. While compounds 4b-d show thermal stability up to 250 °C, compounds 8 are stable up to 216–235 °C. The structures of all products were confirmed by IR, 1H and 13C NMR spectroscopic methods, in case of 8b also by XRD analysis.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Pyrrolo[1,2-a]perimidin-10-one dyes were synthesized via two convenient methods. ► Novel dyes were characterized by molecular spectroscopic methods. ► The synthesized dyes show thermal stability up to 250 °C. ► UV–vis spectra of dyes showed maximum absorption bands in the ranges 381–439 nm.