Efficient and one‐pot catalytic synthesis of 2‐imidazolines and bis‐imidazolines with p‐toluenesulfonic acid under solvent free conditions

Abstract

A practical, efficient, and inexpensive method for the synthesis of 2‐imidazoline from the reaction of nitriles with ethylenediamine or 1,2‐propanediamine using p‐toluenesulfonic acid or pyridinium p‐toluenesulfonate under reflux conditions is reported. This catalyst can be successfully applied for the chemoselective conversion of dicyanobenzenes to corresponding mono‐ and bis‐imidazolines. The applications of these catalysts are feasible because of easy preparation, easy handling, stability, inexpensive, good activity, and eco‐friendly. J. Heterocyclic Chem., (2011).

Recent Advances in the Synthesis of Imidazolines (2009–2020)

“…Nasr-Esfahani and co-workers reported another synthetic method of imidazoline synthesis, by using ethylenediamine or 1,2-propanediamine (40) with nitriles or dinitriles (39) in the presence of ptoluenesulfonic acid (p-TSA) or pyridinium p-toluenesulfonate (PPTS) (Scheme 10). [33] The reaction proceeds with a high yield of both mono-and bisimidazolines (41) (72-92%). Mono-imidazolines were formed in 90-92% yields when ethylenediamine was treated with dinitriles for a short period of time (50-60 min).…”

Highly Practical Synthesis of Nitriles and Heterocycles from Alcohols under Mild Conditions by Aerobic Double Dehydrogenative Catalysis

“…This aerobic double dehydrogenative nitrile synthesis was tied to various heterocyclization processes, to provide a one-pot synthesis of substituted tetrazoles, imidazolines, oxazoline, thiazoline, and triazolopyridines (Scheme ). Generally, the reagents for the heterocyclizations were introduced after a full conversion of nitrile had been achieved.…”

Copper-Catalyzed N-Arylation of 2-Imidazolines with Aryl Iodides

“…Despite the number of methods to prepare N -unfunctionalized imidazolines, , approaches to further derivatize these units by formation of C–N bonds are limited to reactions with activated alkylating agents and carbonyl derivatives. To date there are only two reports of C(sp 2 )–N cross coupling involving imidazolines, both using Pd catalysis, and these are limited to very electron-poor aryl halides. , The ability to efficiently link (hetero)aromatics to imidazolines in this manner would allow rapid access to a wider range of derivatives, thus opening up new areas of lead-like or fragment chemical space (Scheme ).…”