Green oxidations: Titanium dioxide induced tandem oxidation coupling reactions

• Vineet Jeena and
• Ross S. Robinson

Beilstein J. Org. Chem. 2009, 5, No. 24, doi:10.3762/bjoc.5.24

• , quinoxalines have been synthesized in good yields from the corresponding α-hydroxyketones. Keywords: quinoxalines; tandem oxidation process; titanium dioxide; Introduction Titanium dioxide has found widespread industrial application ranging from whiteners in paint [1], and additives in food [2], to UV

• . Herein, we describe the application of titanium dioxide in conjunction with 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO) as an oxidant in the synthesis of quinoxalines, via the tandem oxidation process (TOP) (Scheme 1). Results and Discussion Titanium dioxide in the anatase phase is a

• mediated synthesis of quinoxalines. Evaluation of energy sources. Titanium dioxide catalysed tandem oxidation process under microwave irradiation. Supporting Information Supporting information features experimental procedures and spectroscopic analysis for compounds 3a–3g coupling reactions. Supporting