To obtain the subject compound useful for a precursor compound in the field of hair cosmetics by decreasing the amount of impurities having the danger of allergy attraction and by controlling discoloration least possible.
By catalytically hydrogenating 1-substituted 2,4-dinitrobenzenes, wherein R1 is a 1-20C alkyl, an aryl or the like; R2 is expressed by formula II [wherein R5 is a 1-5C alkyl; (m) is 1-12 and; (p) is 1-4 or formula III [wherein (r) is 0-2] and; (n) is 0-3} and by adding the catalyst-free reaction product to an aqueous solution of an acid of the formula H(+)Y(-) (e.g. hydrochloric acid), the objective compound of formula IV is obtained. The hydrogenation reaction is carried out in the presence of a precious metal catalyst under a hydrogen pressure of 0.5-5 MPa at 40-120°C in a solvent being an aliphatic alcohol (e.g. isopropanol). The molar ratio of the acid to the compound of formula I preferably is 2:1.
KLAUSENER ALEXANDER
BEHRE HORST
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