Vicinal tricarbonyl intermediates are directly synthesized from β-dicarbonyls with the aid of Cu(II) salts and air, and they are further condensed with phenylene diamine to produce a range of quinoxalines in moderate to good yields in one-pot reaction.
The catalyst-free one-pot synthesis of quinoxaline-2-carboxylate is reported by the reaction of alpha-halo-beta-ketoesters with 1,2-diamines using an ionic liquid as an environmentally benign solvent The recovered ionic liquid was reused for four to five cycles Moreover, the method is applicable for a variety of 1,2-diamines and alpha-halo-beta-ketoesters (c) 2010 Elsevier Ltd All rights reserved
2-[[(p-Nitrophenyl)sulfonyl]oxy]-3-keto esters: versatile intermediates for the preparation of 1,2,3-tricarbonyl compounds