Halogen- and methyl-substituted xanthones have been prepared by three routes. The main approach has been Friedel-Crafts acylation-cyclization of aromatic ethers with oxalyl chloride or with chloroacetyl chloride followed by permanganate oxidation. The substituent shifts in the 1H NMR spectra of the compounds studied are in good agreement with those predicted for substituted benzene derivatives. The typical electron-impact-induced CO expulsion from the molecular ion of xanthone decreases or even disappears in the halogenated derivatives owing to the competing halogen elimination.
ASJC Scopus subject areas
- Organic Chemistry