Phosphatoblei(IV)‐säuren als Oxydationsmittel zur Darstellung von Benzoxazolen, Benzimidazolen und Benzthiazolen

Oxidation of N-benzylidene-2-hydroxyaniline by dioxygen catalysed by a dicobalt complex †

“…In the presence of dehydration agent this catalysed oxidation method gives a yield of benzoxazole or its derivatives that is equal or better than any other oxidation method in the literature. [28][29][30][31][32][33] Based on the isolated yields, the turnover numbers of the dicobalt complex 1 for the oxidation of compound Ia in the absence and presence of dehydrating agent are 67 and 87, respectively. We would point out that the C᎐ ᎐ N bonds in 1 might be susceptible to hydrolysis.…”

“…The oxidants that have been used include nickel peroxide, 28 silver oxide, 29 lead() tetraacetate 30, 31 and lead() phosphate. 32 Oxygen has also been employed as the oxidant with a copper() salt as the catalyst. 33 However, a large amount of catalyst (substrate, 5 mmol; Cu I , 2 mmol) was required in this Cu Icatalysed reaction.…”