The total synthesisofd ehydroantofine was achieved by employing an ovel, regioselective, azahetero Diels-Alder reaction of easilya ccessible 3,5-dichloro-2H-1,4-oxazin-2-one with 14 a as ak ey step. Furthermore, it is demonstrated that dehydroantofinei sapromisingc andidate as an ew antimalarial agent in ab iological assay with chloroquine-resistant Plasmodium falciparum.

We developed a one-step synthesis of acylborons from both readily available acyl chlorides and bis(pinacolato)diboron through copper(I)-catalyzed borylation. Under the reaction conditions using t BuOLi, polystyrene-supported triphenylphosphine as a copper ligand was found to promote the borylation of acyl chlorides while suppressing alcoholysis. This method enables the facile synthesis of potassium acyltrifluoroborates.

The 1H-2-benzopyran-5,8-dione structure was synthesized by a cascade reaction through Michael addition, elimination of HBr, and O-alkylation between a dibromobenzoquinone derivative and β-ketoesters under basic conditions. The reaction using potassium carbonate and 18-crown-6 in THF was the best condition, giving 1H-2-benzopyran-5,8-dione derivatives in good yields. The UV-vis absorption spectrum and cyclic voltammogram of the synthesized 1H-2-benzopyran-5,8-dione derivative were measured, clarifying the photophysical and redox properties.

-(2,4-dinitrophenyl)pyridinium ion of nicotinamide with enol ether. [7]