Oxidation of Phenacetin and Related Amides to Their Hydroxamic Acids

Alternative Title

Crystal structures of the dioxomolybdenum(VI) hydroxamates derived from phenacetin and acetanilide


An existing method of oxidation involving oxodiperoxo(hexamethylphosphoramide)molybdenum(VI) has been adapted for the direct conversion of phenacetin and related amides to their respective hydroxamic acids. The hydroxamic acids are initially isolated as their stable dioxomolybdenum(VI) salts, in which form they can conveniently be stored and from which they are readily liberated by ligand displacement. The hydroxamic acids are of interest as the suspected toxic metabolites of several related drugs. The Mo(VI) derivatives of two analgesics, phenacetin and acetanilide, have been characterized by single-crystal X-ray diffraction. The ligand environment about the Mo atom is a markedly distorted octahedron in each case, with the dioxo O atoms bonded cis to each other, while trans to these bonds the hydroxamate Mo-O bonds are elongated. There is no conjugation between the phenyl rings and the hydroxamic acid group. Crystal data: MoO2L2, space group P21/c, Z = 4, a = 12.350 (6) Å, b = 17.477 (3) Å, c = 10.309 (7) Å, β = 95.25 (3)°, V = 2216 Å3, R = 5.0%, 2738 reflections; MoO2L′2, space group Pbca, Z = 8, a = 13.137 (3) Å, b = 11.620 (3) Å, c = 22.820 (5) Å, V = 3483 Å3, R = 4.7%, 1549 reflections. L and L′ represent the hydroxamate anions derived from phenacetin and acetanilide, respectively. © 1981 American Chemical Society.



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© 1981 American Chemical Society (ACS), All rights reserved.