A Greener and Efficient Method for Nucleophilic Aromatic Substitution of Nitrogen-Containing Fused Heterocycles

Abstract

A simple and efficient methodology for the nucleophilic aromatic substitution of nitrogen-containing fused heterocycles with interesting biological activities has been developed in an environmentally sound manner using polyethylene glycol (PEG-400) as the solvent, leading to the expected compounds in excellent yields in only five minutes.

The First Catalytic Direct C–H Arylation on C2 and C3 of Thiophene Ring Applied to Thieno-Pyridines, -Pyrimidines and -Pyrazines

“…With a view to developing procedures with the lowest possible environmental impact, we tested the use of PEG 400 as solvent. This compound, like the other heterocyclic scaffolds, underwent the SnAr reaction using amines and produced good yields in only 5 min [23], but our goal was to diversify our core structure by C-H activation which tried using Polyethylene glycol 400 as solvent without success in a one-pot process. We therefore decided, in the present work, to use toluene with various amines to generate precursors of C-H catalyzed cross-coupling.…”

Demonstration of Green Solvent Performance on O,S,N-Heterocycles Synthesis: Metal-Free Click Chemistry and Buchwald—Hartwig Coupling

“…Therefore it seemed relevant to compare it to other ether-type solvents deemed to be green. In order to continue to develop new and green methods to construct heterocyclic rings containing oxygen, sulfur, and nitrogen [ 10 , 11 , 12 , 13 , 14 ], we report here the use of eucalyptol (1,8-cineole), cyclopentyl methyl ether (CPME), and 2-methyltetrahydrofuran (2-MeTHF) as alternative solvents for metal-free click chemistry and Buchwald–Hartwig coupling ( Figure 1 ). 2-methyltetrahydrofuran (2-MeTHF) is already well known to generate fewer peroxides than when tetrahydrofuran (THF) is obtained from renewable corncobs and bagasse resources.…”

Laser synthesis: a solvent-free approach for the preparation of phenylthiazolo[5,4-b]pyridine derivatives

“…Considering the above, it seemed important to explore this synthesis approach in order to improve general knowledge in the eld of new and greener synthetic strategies for the construction of O,S,N-heterocycles. [12][13][14][15][16][17][18][19][20][21] To prepare the benzothiazole skeleton, and aer reviewing the literature, we found that Ramakrishnan's team had successfully used the potential of photochemical synthesis. The photocyclization of halogenated thioacetanilides gave a high yield of halogenated 2methylbenzothiazoles (Scheme 1a).…”