Unexpected simultaneous synthesis of trisubstituted quinolines and acylhydrazones under catalyst-free conditions

ABSTRACT

Trisubstituted quinolines and acylhydrazones were unexpectedly prepared from a reaction of N′-((2-aminophenyl)(phenyl)methylene)benzohydrazides with acetylenic esters. Using of N′-((2-aminophenyl)(phenyl)methylene)benzohydrazides led to obtain not only quinoline, but also a second pharmaceutical important product acylhydrazone. Notably, excellent yields, operational simplicity, short reaction times, and the avoidance of the use of catalysts make this approach an attractive complementary method to produce quinoline-2,3-dicarboxylates. The crystal structure of 5a was determined using single-crystal X-ray crystallography. The results showed that crystal packing diagram of 5a is of two pairs of molecules that have two independent alternate intermolecular 1D-polymeric H-bonds between two perpendicular molecules.

GRAPHICAL ABSTRACT

KEYWORDS:

• Acylhydrazone
• catalyst free
• quinoline-2,3-dicarboxylate
• unexpected simultaneous synthesis
• X-ray crystallography

Acknowledgments

The authors are grateful to University of Mohaghegh Ardabili for the financial support and the laboratories of Tehran, Tabriz, and Atatürk Universities for analyzing the products.