Storage stable 2-methyl-1-naphthol couplers

In a method for producing an oxidative hair dye wherein a peroxide containing composition is mixed with an alkaline composition containing a primary intermediate and a coupler, the improvement comprising the coupler is a compound of formula IIb ##STR14## wherein R.sub.4 is --OCH.sub.3, --OCH.sub.2 CH.sub.3, --OCH.sub.2 CH.sub.2 OH or --OCH.sub.2 CH.sub.2 OCH.sub.3, the alkaline composition contains monoethanolamine or aminomethylpropanol as the alkalizing agent, and the alkaline composition is maintained at ambient temperature.

In a method for producing an oxidative hair dye wherein a peroxide containing composition is mixed with an alkaline composition containing a primary intermediate and a coupler precursor, the improvement comprising the coupler precursor is a compound of formula IIa ##STR15## wherein R.sub.3 is --COOCH.sub.3, --COCH.sub.3 or --COCH.sub.2 CH.sub.3, the alkaline composition contains monoethanolamine, aminomethylpropanol or ammonia as the alkalizing agent, and the alkaline composition is maintained at ambient temperature.

A method for reducing undesired by-products in an oxidative hair dye prepared by reacting an oxidant with an alkaline composition containing an alkali, a primary intermediate and a 2-methyl-1-naphthol derivative, said method comprising preparing said alkaline compositions by dissolving in an aqueous vehicle (i) an amount of a compound of formula IIa wherein R.sub.3 is --COOCH.sub.3, --COCH.sub.3 or --COCH.sub.2 CH.sub.3 ##STR16## (ii) said primary intermediate, and (iii) an alkali selected from the group consisting of monoethanolamine, aminomethylpropanol and ammonia;

• then mixing the alkaline composition with the oxidant to produce an indo dye that is identical to one that would be produced had the alkaline composition contained 2-methyl-1-naphthol rather than the compound of formula IIa wherein R.sub.3 is --COOCH.sub.3, --COCH.sub.3 or --COCH.sub.2 CH.sub.3.

A method for reducing undesired by-products in an oxidative hair dye prepared by reacting an oxidant with an alkaline composition containing an alkali, a primary intermediate and 2-methyl-1-naphthol substituted at the 4-position by --OCH.sub.3, --OCH.sub.2 CH.sub.3, --OCH.sub.2 CH.sub.2 OH or --OCH.sub.2 CH.sub.2 OCH.sub.3, said method comprising preparing said alkaline composition by dissolving in an aqueous vehicle (i) an amount of a compound of formula IIb wherein R.sub.4 is --OCH.sub.3, --OCH.sub.2 CH.sub.3, ##STR17## --OCH.sub.2 CH.sub.2 OH or --OCH.sub.2 CH.sub.2 OCH.sub.3, (ii) said primary intermediate, and (iii) an alkali selected from the group consisting of monoethanolamine and aminomethylpropanol;

• then mixing the alkaline composition with the oxidant to produce an indo dye that is identical to one that would be produced had the alkaline composition contained 2-methyl-1-naphthol rather them the compound of formula IIb wherein R.sub.4 is --OCH.sub.3, --OCH.sub.2 CH.sub.3, --OCH.sub.2 CH.sub.2 OH or --OCH.sub.2 CH.sub.2 OCH.sub.3.

In an oxidative dye system for dyeing a keratin fiber wherein an oxidant is reacted with a composition containing a primary intermediate, a coupler or a coupler precursor, an alkalizing agent selected from the group consisting of monoethanolamine and aminomethylpropanol, and a cosmetically acceptable vehicle therefor, the improvement which comprises the coupler or the coupler precursor is a compound having the formula IIb ##STR18## wherein R.sub.4 is --OCH.sub.3, --OCH.sub.2 CH.sub.3, --OCH.sub.2 CH.sub.2 OH or --OCH.sub.2 CH.sub.2 OCH.sub.3.