Convenient two-step one-pot synthesis of 3-substituted imidazo[1,2-a]pyridines and imidazo[1,2-b]pyridazines

Abstract

A convenient and novel two-step one-pot method for the synthesis of 3-substituted imidazo[1,2a]pyridines and 3-substituted imidazo[1,2-b]pyridazines was developed through the reaction of heterocyclic amines and N , N-dimethylformamide dimethyl acetate with active electrophiles RCH 2 Br (R = CO 2 Et, CN, COPh, 4'-MeO-PhCO and 4'-F-PhCO). This protocol provides a simple and practical approach to 3-substituted fused imidazo-heterocyclic compounds in moderate to high yields.

Recent Advances in the Synthesis of Imidazo[1,2‐a]pyridines: A Brief Review

“…Recently, the synthesis of 3‐substituted imidazo[1,2‐ a ]pyridines was reported by various groups to describe the biological nature of imidazo[1,2‐ a ]pyridines [136] . In the quest to develop a practical and library‐friendly method under mild conditions, Fan et al [137] . reported a novel one‐pot two‐step procedure for the synthesis of 3‐substituted fused imidazo‐heterocyclic compounds 174 in moderate to high yields using heterocyclic amines 171 and N, N ‐dimethylformamide dimethyl acetate with active electrophiles.…”

“…[134] To develop fluorine-containing biologically active molecules, Hariss et al [135] in 2017 reported the synthesis of new derivatives of imidazo Recently, the synthesis of 3-substituted imidazo[1,2a]pyridines was reported by various groups to describe the biological nature of imidazo[1,2-a]pyridines. [136] In the quest to develop a practical and library-friendly method under mild conditions, Fan et al [137] reported a novel one-pot two-step procedure for the synthesis of 3-substituted fused imidazoheterocyclic compounds 174 in moderate to high yields using heterocyclic The low volatility and non-flammability nature of ionic liquids attracted scientists for organic synthesis as alternative reaction media to volatile organic solvents. They have been used in catalysis as a catalyst, catalyst activator, and co-catalyst for various reactions as shown by recent studies.…”

Silica‐Supported P2O5 as an Efficient Heterogeneous Catalyst for the One Pot Synthesis of 3‐Amino‐imidazo[2,1‐b](1,3)benzothiazole under Green Conditions

“…The Groebke–Blackburn–Bienaymé reaction is used for the one‐pot synthesis of therapeutically relevant fused imidazoles bridgehead nitrogen heterocyclic compounds from readily available aldehyde, isocyanide, and aminoazines building blocks . 3‐Amino‐imidazo[2,1‐ b ] azine or azoles have been reported to exhibit significant biological activities such as antibacterial, antifungal , anti‐inflammatory, anticancer and analgesic activity , antiviral, antiparasitic, antituberculosis , modulators of sodium channels, ubiquitin ligase inhibitors, hystone deacetylase inhibitors, and G‐protein coupled receptor ligands . Because of these marked biological activities of N ‐fused bicyclic imidazo‐azines/azole scaffolds , a number of different protocols have been developed for the Groebke reaction (for the synthesis of this type skeletons) .…”