Condensation of benzaldehyde with malononitrile and malononitrile dimer (2-aminopropene-1,1,3-tricarbonitrile) in the presence of an excess of morpholine in ethanol afforded the morpholinium salt of 6-amino-2-(dicyanomethylene)-4-phenyl-1,2-dihydropyridine-3,5-dicarbonitrile. The latter, under the Mannich reaction conditions with the participation of primary amines and formaldehyde, gives 6-amino-2-(dicyanomethylene)-4-phenyl-1,2-dihydropyridine-3,5-dicarbonitrile, 2-(dicyanomethylene)-6-(hydroxymethylamino)-4-phenyl-1,2-dihydropyridine-3,5-dicarbonitrile or zwitterionic aminomethylation products, 6-(ammoniomethylamino)-3,5-dicyano-4-phenylpyridin-2-yl)dicyanomethanides. Structure of the obtained compounds was established using 2D NMR spectroscopy and single crystal X-ray diffraction analysis
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Synthesis and aminomethylation of 6-amino-2-(dicyanomethylene)-4-phenyl-1,2-dihydropyridine-3,5-dicarbonitrile morpholinium salt
Published:
14 November 2021
by MDPI
in The 25th International Electronic Conference on Synthetic Organic Chemistry
session General Organic Synthesis
https://doi.org/10.3390/ecsoc-25-11739
(registering DOI)
Abstract:
Keywords: malononitrile dimer; 2-(dicyanomethylene)-1,2-dihydropyridines; aminomethylation; Mannich reaction