Thermolysis of N‐Aryl Enaminoimine Hydrochloride Derivatives: A Short and General Method for the Synthesis of Pyranoquinolin‐3‐one and Pyranoacridin‐3‐one Derivatives

Thermolysis of Chlorovinyl Imines as an Alternate Route for the Synthesis of Pyranoquinolin‐3‐one and Pyranoacridin‐3‐one Derivatives

“…(mp and spectral data of the pyridocoumarins 5 ( a – c ) and 5 ( e – f ) are in agreement with lit. report ).…”

“…Light yellowish solid, yield 62%; mp 240–242°C (CHCl 3 /pet. ether 60–80°C) (lit mp 240–242°C, ref of ).…”

“…Advantage of thermolysis of chlorovinyl imines to prepare polycyclic aza arenes (PAAs) is that here one equivalent of amine is saved and sometime may be a better method especially when the aryl amine component is costly or difficult to synthesize. Very recently, we have reported the synthesis of some novel polynuclear pyridocoumarin derivatives by thermolysis of anil hydrochlorides derived from various β‐chloro‐α,β‐unsaturated aldehyde derivatives and two equivalents of 6‐aminocoumarin. In our present work, we report a modified method to synthesize pyridocoumarin derivatives by thermolysis of chlorovinyl derivatives derived from various β‐chloro‐α,β‐unsaturated aldehyde derivatives and one equivalent of 6‐aminocoumarin.…”

A Concise Review on Pyridocoumarin/Azacoumarin Derivatives: Synthesis and Biological Activity

“…In 2014 we synthesised novel pyridocoumarin derivatives 188, 189, 191 & 192 by thermolysis of enaminoimine hydrochloride derivatives 187 & 190 starting from different substituted β‐choro α,β‐unsaturated aldehyde and 6‐amino coumarin (Scheme ). The method has a number of advantages such as easy availability of the starting material, short time of the reaction, high yields for anil hydrochloride formation and aromatization of the dihydro pyridocoumarin, though in the thermolysis of anil derivatives the dihydro pyridocoumarin derivatives were obtained in moderate yields, simple procedure and above all, the methods permits the introduction of electron withdrawing or electron donating substituent in the polycyclic azacoumarin frameworks.…”

Synthesis of 5H-Chromeno[4,3-b]pyridin-5-one derivatives as a backbone of natural product polyneomarline C scaffolds in presence of Et3N and NH4OAc in EtOH

“…So the interest towards the synthesis of pyridine fused comarin is trending among the organic chemists. Many methods [20][21][22][23][24][25][26][27][28][29][30] have been developed to synthesize these types of compounds using different types of Lewis acids/bases and metal catalysts with different solvents. The 5H-Chromeno [4,3-b]pyridin-5-one skeleton constitutes the backbone of Polyneomarline C. We were interested in the preparation of some non-natural analogs of this type of compounds by an easy process.…”