Synthesis of pyrano[3,2-c]quinoline-4-carboxylates and 2-(4-oxo-1,4-dihydroquinolin-3-yl)fumarates

• DOI: 10.1007/s11696-017-0269-6
• Publication Date: 2017-08-12T15:17:44Z
• Authors: Essmat M. El-Sheref; Ashraf A. Aly; Aboul-Fetouh E. M...; Alan B. Brown; Stefan Bräse; Momtaz E. M. Bakheet
• Keywords: info:eu-repo/classification/ddc/540; ddc:540; Chemistry & allied sciences; 540; 01 natural sciences; 0104 chemical sciences

Reaction of equimolar amounts of 2,4(1H,3H)-quinolinediones and diethyl acetylenedicarboxylate in absolute ethanol, containing catalytic triethylamine, gave ethyl 5,6-dihydro-2,5-dioxo-6,9-disubstituted-2H-pyrano[3,2-c]quinoline-4-carboxylates in good yields. In a different manner, reaction of two equivalents of dialkyl acetylenedicarboxylates with one equivalent of 2,4(1H,3H)-quinolinediones afforded dialkyl 2(4-oxo-1,4-dihydroquinolin-3-yl)fumarates in good yields. The structures of the products were elucidated by 1H NMR, 13C NMR, two-dimensional NMR, IR, mass spectra and elemental analyses.