Ultrasound promoted three‐component synthesis of dihydroindeno[1,2‐b]pyrrole derivatives

Abstract

In this work, a one-pot three-component reaction of ninhydrin, primary amines, and 1,3-dicarbonyl compounds was investigated under various conditions to synthesis of diverse derivatives of dihydroindeno[1,2-b]pyrroles. Catalyst-free conditions in EtOH under ultrasound irradiation (45% of amplitude) were selected as a novel and efficient method for synthesis of these fused structures. The reactivity of different primary amines was then investigated for steric and electronic effects. Two examples of difunctional structures were also synthesized by using of 1,4-diaminobenzene under optimum conditions with high yields. The structure of all products was characterized by spectroscopic methods and elemental analysis.

POCl3 mediated one-pot deoxygenative aromatization and electrophilic chlorination of dihydroxy-2-methyl-4-oxo-indeno[1,2-b]pyrroles

“…To explore the generality of the reaction on substrate scope, a variety of known dihydroxy-2-methyl-4-oxo-indeno[1,2- b ]pyrroles (1a–i, 14 Table 1 ) were employed in these reactions to the synthesis of diverse 4-oxo-indeno[1,2- b ]pyrrole derivatives. The related products were obtained with moderate to excellent yields (entries 1–15).…”

“…Regard to our recent interest in the study of indenopyrrole structures 14 due to their biological activities, 15 herein, we report an efficient POCl 3 -mediated deoxygenation–chlorination of dihydroxy-2-methyl-4-oxo-indeno[1,2- b ]pyrroles via a cyclic chlorophosphate ester intermediate to achieve novel derivatives of 2-(chloromethyl)-4-oxo-indeno[1,2- b ]pyrrole. Nucleophilic substitution of several nucleophiles, such as H 2 O, EtOH, and NaN 3 , with the chlorine atom, resulted in the related products.…”