An Economical and Eco-Efficient Ammonium Chloride Promoted Friedlander Condensation: A Study of Microwave-Assisted Versus Conventional Heating.

A new approach to Friedlander hetero-annulations reaction is presented here for the synthesis of polysubstituted quinolines and polycyclic quinolines by the use of an inexpensive, nontoxic and readily available NH4Cl promoter. As a promoter, it shows good compatibility with various substrates, its easy removal, no side product, enhances the atom economy and makes the reaction eco-friendly. Both microwave irradiation and conventional heating accomplished the reaction. The present method provides a comparative study of microwave irradiation versus conventional heating.