| 摘要 |
PROBLEM TO BE SOLVED: To use the subject compound generally having excellent solubility in water, a mixture of water/alcohol and a usual dyeing carrier and excellent resistance against various attacking factors to which keratin fibers are exposed even in a case of fibers and useful as a composition for dyeing hair, etc. SOLUTION: This compound is expressed by formula I (R1 and R2 are each H, a 1-6C alkyl, 5- or 6-membered cycloalkyl or the like; R3 and R4 are each H, a 1-6C alkyl, a monohydroxyalkyl or the like; A is S, N, O or the like) and its acid added salt, preferably, 2-(4-amino)phenyl hydrazine carboximidamide, etc. The compound is obtained by reducing a compound of formula II in a solvent such as water or methanol, etc., by using catalytic hydrogenation of a catalyst such as palladium on a charcoal at pH 4-10 and at about 0-60 deg.C. |
