Catalytic oxidations using cobalt(II) complexes - Advances in Catalytic Activation of Dioxygen by Metal Complexes - page 303

N -benzylidene-2-hydroxyaniline (Bha) and its related derivatives (a-f,
Figure 47) can be catalytically oxidized by in the presence of the

hydroxo-bridged dicobalt complex (Figure 46)

in DMF at 90°C 145 .

The oxidation products were the corresponding 2-substituted benz-
oxazoles (Box), formed in yields higher than 90% (Figure 47).
Hydrolysis of the starting compound with water produced 2-aminophenol
in a side reaction. It was oxidized to 2-aminophenoxazine-3-one. Galvinoxyl
radical did not affect the rate of oxidation, therefore no free radical reactions
seem to be involved.