Synthesis of pyrrole derivatives via ring closing metathesis, Clauson-Kaas reaction and Paal-Knorr condensation as key steps

Herein, we report three simple methods for the synthesis of pyrrole derivatives starting with commer-cially available amines. Using Grubbs first-generation catalyst (G-I) one pot ring closing metathesis (RCM) and aromatization sequence was realized to assemble pyrrole deivatives without the use of any additional reagents. The second and third methods rely on, the condensation of 2,5-hexanedione/2,5-dimethoxy tetrahydrofuran in the presence of a low melting mixture of N, N'-dimethylurea (DMU) and L-( + )-tartaric acid (TA) and glacial acetic acid to produce substituted pyrroles in excellent yield. We also studied the photophysical properties of these molecules by fluorescence spectroscopic data which possess good quan-tum yield ( OF ).(c) 2022 Elsevier B.V. All rights reserved.

Automated summary

In this paper, three simple methods for the synthesis of pyrrole derivatives starting with commercially available amines were reported. The first method achieved one-pot ring closing metathesis (RCM) and aromatization sequence using Grubbs first-generation catalyst (G-I), without the use of any additional reagents. The second and third methods relied on the condensation of 2,5-hexanedione/2,5-dimethoxy tetrahydrofuran in the presence of a low melting mixture of N, N'-dimethylurea (DMU) and L-(+)-tartaric acid (TA) and glacial acetic acid, resulting in substituted pyrroles with excellent yield. The photophysical properties of these molecules were also studied by fluorescence spectroscopic data, showing good quantum yield (OF).