Three-Component Cycloaddition of Nitriles: Construction of Bicyclic 4-Aminopyrimidines and Their Photophysical Studies

Abstract

A base-induced synthesis of bicyclic 4-aminopyrimidines by the cycloaddition of three types of nitriles is reported. The scope of the method is demonstrated with 44 examples. Products are found to have luminescence properties and show potential applications as organic luminescent layer materials.

Copper-Catalyzed Oxidative [3 + 2] Cycloaddition of N-Alkyl Pyridinium Salts to Imidazo[1,2-a]pyridines

“…We recognized that the major obstacle to achieving the reaction of pyridines is overcoming the thermodynamic stability associated with the aromaticity of the pyridine ring. Inspired by the recent reports stating that the use of pyridinium salts can weaken the inertness of pyridine and activate the second position of the pyridine ring, combined with our ongoing interest in C–N bond formation, we herein report the first conversion of pyridinium salts to 2-cyanoimidazo­[1,2- a ]­pyridines by copper-catalyzed cascade dihydro cyanation/cyclization in the presence of diethyl phosphite. Trimethylsilyl cyanide (TMSCN) plays a dual role not only as the “CN” source but also as the coupling partner for the cyclization of imidazo­[1,2- a ]­pyridines.…”