3, 4-Disubstituted 4-deazatoxoflavin derivatives (II) were prepared by the condensation of 6- (1-methylhydrazino) uracils (I) with appropriate α-diketones. The compounds II oxidized long- chain alkylamines such as n-octylamine and n-dodecylamine besides benzylamine and cyclohexylamine to yield the corresponding carbonyl compounds via imines, catalytically with a markedly high turnover number.