2 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS presence of water and alcohol (6). These treatments are claimed to give the hair good settability and curl retention. The improvement of set stability of wool fabrics was also achieved by reacting the wool with Bunte salt containing polymers (7). The area of reactive dyes for wool has been explored for over 20 years. The dyes with reactive moieties assure a high substantivity to wool protein, and consequently wash- fastness of the dyeouts. Currently, reactive dyestuffs containing ot-bromoacrylamido, 2,4-difiuoro-5-chloropyrimidyl, and [•-sulphato- or N-methyltaurine-ethylsulfone groups are commercially available (8). These compounds are, however, too reactive and probably not safe enough to be considered for use in consumer products such as hair dyeing compositions. In 1975 Guise and Stapleton showed that the isothiuronium group could be useful for the fixation of dyes to wool textiles (9, 10). The process involves the absorption of water-soluble dye into the fiber at neutral pH, high pH hydrolysis of the isothiuronium to the mercapto group, followed by the thiol-disulfide exchange reaction with the fiber protein, or oxidation with the formation of water-insoluble, disulfide-linked dimeric dye molecules or a keratin-dye product. A similar mechanism of binding of thiol or disulfide-containing dyes to wool was reported by Asquith et al. (11,12). A review of the subsequent patent literature revealed the use of isothiuronium compounds as reac- tive dyestuffs for cellulose and wool (13). This technology has not been extensively used in the personal care industry (14), although it can be potentially useful in making cosmetic treatments such as dyes and conditioners more durable. The purpose of this investigation was to ascertain the effect of incoporation of the isothiuronium moiety into cationic surfactants and dyestuffs on their durability (measured by resistance to shampooing) as dyeing and conditioning agents. EXPERIMENTAL MATERIALS Samples of hair. The hair used in this work was purchased from DeMeo Brothers, New York. The hair used in the adsorption and combing experiments was commercially blended virgin brown hair. It was washed with 5% Triton X-100 (Rohm and Haas) and thoroughly rinsed under running deionized water. Hair samples were then soaked in three 500-ml water baths for 15 min each to insure removal of residual surfactant. Hair ø C swatches were dried in vacuo at 37 , and chopped into 2-4-mm-length pieces for use in adsorption experiments. The hair used in dye evaluation experiments was commercially blended gray or pied- mont hair. The blended gray hair was characterized by Hunter tristimulus values of L = 30.36, a = -0.29, andb = 5.47. Dyes (Scheme I). HC Yellow 2 (2 2-(2-nitroanilino)ethanol). Ten grams (70.9 mmol) of 2-nitrofluorobenzene [1] was stirred in 50 g of 2-aminoethanol at 80øC under argon until the starting material was completely reacted. The reaction mixture was poured onto ice, filtered, and recrystallized from 2-propanol to give 10.6 g (82%) of 2. 1-Mesyloxy-2-(nitroanilino)ethane [3]. Compound 2 (10 g 54.9 mmol) was dissolved in 150 ml of anhydrous THF and 5.6 g of dry triethylamine. Methanesulfonyl chloride (6.3 g 55.5 mmol) was added dropwise, while cooling the reaction vessel in an icebath.

DYES AND SURFACTANTS FOR HAIR 3 Scheme I. 0 F HNCH• CH•OH HNCH• CH•O--S-•CHa H•NCH•CH•I]H • CHsSõ •CI , s 1. H•N•NH• 2. Dowex 50W + _ HNCH•CH•__S•C• NH•X •NH• 4a : X-= CHaSOa- 4b : X-= C1- When addition was complete, the reaction mixture was stirred at room temperature overnight, then filtered to remove the triethylamine hydrochloride. Evaporation of the solvent gave 14.2 g (99%) of 3 as an orange solid. N-(2-isothiuranylethyl)-2-nitroaniline chloride [4]. Compound 3 (2.6 g 10 mmol) and thiourea (1.12 mmol 2 equiv.) were dispersed in 20 ml of absolute ethanol and re- fluxed for 48 hours. Chromatography on silica gel with CHCI 3 gave 2.25 g (69%) of 4a. This material was stirred with a 15:1 excess of the chloride form of Dowex 50W ion exchange resin to obtain the chloride salt, 4b, in quantitative yield from 4a. Surfactants (Scheme II). Dimethyl-(2-hydroxyethyl) hexadecyl bromide [5] and methyl- di[(2-hydroxyethyl)]-hexadecyl ammonium bromide [8] were prepared by quaterniza- tion of dimethyl ethanol amine or methyl diethanoi amine with hexadecyl bromide in acetonitrile. Scheme II. CHa X- CHa X- S CHa X- +l --NH• Br +1 PBr3/Benzene +1 II - H2NCNH2 R•N•CH•CH•0H , R•N--CH•CH•Br , R•--N--CH•CH•S• I I