One-pot Synthesis of Quinoxaline Chalcones from Commercially Available Calcium Carbide Through Palladium-Catalyzed Coupling Reactions

New (E)-3-(2-aminoquinoxalin-3-yl)-1-arylprop-2-en-1-ones are prepared through the multi-component reaction of 3-substituted-2-chloroqunoxalines, calcium carbide, and aromatic aldehydes in the presence of diethylamine, catalyzed by Pd/Cu in acetonitrile. This synthetic strategy presents an acetylene molecule linking the quinoxaline scaffold to an aldehyde moiety for construction of quinoxaline chalcone by two carbon-carbon bond coupling reactions. This one-pot process provides an efficient and direct method for the synthesis of new quinoxaline chalcones from the low-cost calcium carbide with good yields. A number of synthesized compounds were screened for their in vitro anti-bacterial activity against Gram-positive and Gram-negative bacteria using a well-diffusion method.