2,2′-((1,4-Dimethoxy-1,4-dioxobutane-2,3-diylidene)bis(azanylylidene))bis(quinoline-3-carboxylic acid)

Abstract

The title compound, 2,2 -((1,4-dimethoxy-1,4-dioxobutane-2,3-diylidene)bis(azanylylidene)) bis(quinoline-3-carboxylic acid) was synthesized from isoxazolo[3,4-b]quinolin-3(1H)-one and dimethyl acetylenedicarboxylate (DMAD) via a double aza-Michael addition followed by [1,3]-H shifts. The product was characterized by infrared and nuclear magnetic resonance spectroscopy, as well as elemental analysis and high-resolution mass spectrometry (HRMS). The proposed reaction mechanism was rationalized by density functional theory (DFT) calculations.

Nitrogen-Containing Molecules: Natural and Synthetic Products including Coordination Compounds

“…The authors reported the synthesis of a bis-quinoline carboxylic acid derived from the corresponding isoxazolo-quinoline and dimethyl acetylenedicarboxylate (DMAD) under mild alkaline conditions. DFT calculations revealed that the product was more favorable than the double Michael addition isoxazolone product, which according to the proposed by the authors' mechanism, is formed as an intermediate [5].…”