COLORING WITH SEMIPERMANENT DYES 389 these, 64 (70%) failed to pass the substantivity test and were therefore eliminated. This left 29 dyes that were given the light fastness and age- ing tests. Of these, 12 (about 41%) failed to pass the light fastness and 6 (about 21%) failed to pass the ageing test. In other words, only 13% of the regular solvent-soluble dyes evaluated passed these tests. Preparation of Indophenols and Indamines Indophenols are formed by the oxidation of equimolar quantities of a p-aminophenol and a phenol. Indamines are formed by the oxidation of equimolar quantities of a p-phenylenediamine and a phenylamine. These reactions are shown as follows (36): HO•NH2 + •OH O, (CHa),,N•NH2 + •NH• Indophenol (CHa)2N•N==•NH Indamine Although the reactions have been reported to be affected by various oxidizing agents (37), the sodium hypochlorite method has been used for our preparations. A typical formula for the preparation of an indamine is the following: 6.8 g (0.05M) of p-aminodimethylaniline is dissolved in 350 ml of water and another solution is made by dissolving 5.4 g (0.05M) of m-phenylenediamine and 1.5 g of sodium hydroxide in 150 ml of water. The two solutions are mixed, then cooled to 0øG by adding ice. Next, 115 ml of sodium hypochlorite (5%) solution are added slowly, with stirring, keeping the temperature below 5øG during the ad- dition. The mixture is stirred for 30 min after the last addition without further cooling, then filtered and dried. The yield was 82%. Isopropyl alcohol was used, in some of our preparations, to replace some of the water, with the amount used depending on the solubility of the intermediates. The final pH of the dye preparation solution was about 9.9. After the solution had been filtered, the flitrate was acidified with acetic acid to a pH of 6.0 and any precipitate formed was removed by filtration. In some preparations, as in the one given above for indamine, a substantial yield of dye was obtained upon filtration of the basic solu- tion, while with other intermediates most or all of the dye was obtained upon filtration of the acid solution. It is well known that the oxidation of p-phenylenediamine with hy- drogen peroxide in alkaline solution yields Bandrowski's base which has

390 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS three phenyl groups in its structure. In order to determine whether Bandrowski's base is also formed when sodium hypoch!orite is used as the oxidizing agent p-phenylenediamine was subjected to the treatment shown above, except that the solution was acidified to a pH of 6.0 before filtering. A 62% yield of oxidation product was obtained which, upon reprecipitation from a pyridine solution by the addition of a large amount of water, melted at 236øC. Bandrowski's base that had been prepared by the slow oxidation of an alkaline solution of p-phenylenedi- amine with hydrogen peroxide and reprecipitated in the same way melted at 236øC. The mixed melting point was also 236øC, indicating that the two compounds were the same. Intermediates used in Preparation of Indophenols and lndamines Two types of compounds were used for the formation of indophenols and indamines. The first were para-substituted compounds which, in order to discourage the formation of products having more than two phenyl rings, contain only one free amino group. These were coupled with phenols that have the position para to the hydroxy group free with aminophenols that have the position para to the hydroxy or the amino group free and with phenyl amines that have the position para to the amino group free. There are a great many para compounds that can be used but, in order to limit the scope of this paper, the five listed in Table VII are the only ones considered. For the same reason the phenols used are limited to those listed in Table VIII the aminophenols to those in Table IX and the phenylamines to those in Table X. Table VII Para Compounds used in Indophenol and Indamine Formation A. p-Aminodimethylaniline B. p-Aminoacetanilide C. p-Aminophenol D. 2,6-Di•nethyl-p-aminophenol HCI E. 2,6-Dibrorno-p-aminophenol (CH3)2N•NH2 HO•NH2 gr HO•NH2 Br CH,•C0••NH2 (CHa) H0•NH,2HC1 (CH•)