Methyl 3-aroyl-4-oxo-1,4-dihydroquinoline-2-carboxylates: synthesis and molecular and crystal structures

Thermal decarbonylation of methyl 1-aryl-3-(het)aroyl-4,5-dioxo-4,5-dihydro-1H-pyrrole-2-carboxylates afforded 8-substituted methyl 3-(het)aroyl-4-oxo-1,4-dihydroquinoline-2-carboxylates. X-ray diffraction studies revealed no hydrogen bonds in the crystals of the compounds obtained. According to spectral data, hydrogen bonding is possible in concentrated solutions of 8-substituted methyl 4-oxo-1,4-dihydroquinoline-2-carboxylates.