4-Nitrotoluene → N-(4-Methylphenyl)hydroxylamine

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Reaction Steps

In the above-described reaction schematic, N-(p-methylphenyl)-hydroxylamine (III) can be obtained from p-nitrotoluene (II) using the nitrobenzene reduction method as described in, for example, H. Gilman, Organic Syntheses, Collective Vol. 1, 2nd Ed., pp 445-447 (1961), John Wiley & Sons, Inc., N.Y., or Y. Ogata et al, J. Am. Chem. Soc., 86, pp 3854-3858 (1964). More specifically, for example, 1 mole of p-nitrotoluene (II) is reduced with 2 moles of zinc dust in a solution of 1 mole of ammonium chloride, and the resulting product is recrystallized from a benzene-petroleum ether mixture to obtain Compound (III) having a melting point of 94° C. Subsequently, Compound (III) is treated with a 5% sulfuric acid aqueous solution while cooling to approximately 0° C., e.g., in accordance with the method described in S. Goodwin et al, J. Am. Chem. Soc., 79, pp 179-185 (1957). After extracting the resulting product with chloroform, the concentrate thus obtained is purified with a diethyl ether-benzene mixture on a silica gel chromatographic column to obtain pure p-toluquinol (IV) having a melting point of 76° to 78° C. Compound (IV) is then partially hydrogenated in ethyl alcohol with a 5% Pd/C catalyst at room temperature (e.g., about 20°-30° C.) under a hydrogen pressure of one atm. to obtain Compound (I) having a boiling point of 101.5° to 109.5° C./2 mmHg.

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