REACTION OF a-HYDROXYMETHYL KETONES TABLE II The Reaction of Amino Acids with a-Hydroxymethyl Ketones on Filter Paper 779 Time for Reaction with Aspartic Glutamic Ketone Derivative Glycine a-Alanine •-Alanine Acid Acid Arginine p-Nitrophenacyl alcohol hrs. hrs. min. days days min. Phenacyl alcohol hrs. hrs. min. days days min. p-Bromphenacyl alcohol* days days hrs ....... hrs. p-Dimethylaminophenacyl days days days ...... days alcohol* Dihydroxyacetone hrs. hrs. min. days days hrs. Reactions performed as described in the text, using 1% solutions of amino acids and 10% solutions or saturated solutions (marked*) of a-hydroxymethyl ketones. Reaction times to first appearance of color are recorded as minutes = 1-15 min. hrs. = 2-5 hrs. days = 11•-2 days. In order to investigate further this type of reaction with skin keratin, samples of 100 mg. of callus (ground to 60 mesh) were suspended in 15 mi. of a 5% solution of the a-hydroxymethyl ketone in ethanol. The samples were allowed to remain overnight at room temperature. The alcohol was then poured off and the callus washed three times with 15 mi. portions of alcohol and two times with 15 ml. portions of ether. It was then allowed to dry, and the color development was observed. The results are presented in Table IV. A second sample of ground callus was pretreated with formaldehyde before reacting with the a-hydroxy- methyl ketones. The results are included in Table IV. Since some of the hydroxymethyl ketones possess a slight color them- selves (p-nitrophenaeyl alcohol), it was of interest to ascertain that the color produced on the callus was not the result of simple adsorption. While many materials which impart color to keratin by simple adsorp- tion can be effectively removed with an aqueous sodium chloride-acetone solution, the colors produced by the above materials were not affected by washing the callus with such a solution. In the above experiments, color production was the only criterion used to detect reaction between callus and the test compounds. Several other methods were investigated to see whether the reaction could be detected. 1. Comparison of the I.R. spectra of samples of treated and un- treated callus showed no differences in their spectra. 2. Comparison of the U.V. spectra of thin sheets of skin (carefully removed from the backs of sunburned subjects), before and after treat-

780 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS TABLE III The Reaction of Amino Acids with a-Hydroxymethyl Ketones in Solution Alaninc Phenyl Alaninc Cystinc Dihydroxyacetone brown liquid brown liquid yellow solid Hydroxyacetone brown liquid brown liquid yellow solid Phenacyl alcohol tan solid yellow solid white solid p-Bromophenacyl pink solid gold solid white solid alcohol Reactions performed as described in the text, using 0.05 g. of amino acid and 1% solutions of the a-hydroxymethyl ketone in ethanol. Table indicates colors observed after ethanol evaporated on steam bath. TABLE IV Colors of Callus Samples Treated with a-Hydroxymethyl Ketones Untreated Callus Callus Pretreated with Formaldehyde Dihydroxyacetone Hydroxyacetone Phenacyl alcohol p-Bromophenacyl alcohol p-Hydroxyphenacyl alcohol p-Nitrophenacyl alcohol p-Dimethylamino phenacyl no color alcohol 3,5-Dichloro-4-hydroxy- light tan phenaeyl alcohol dark brown no color light tan no color light yellow no color ydlow-gold no color v. lt. tan no color dk. yellow-brown light yellow ß . . Reactions performed as described in the text, using 100 mg. callus and 5% ethanolic solu- tions of the a-hydroxymethyl ketone. merit with the a-hydroxymethyl ketones, indicated no detectable change in the spectra. 3. Comparison of the water-binding capacity of callus before and after treatment with the test materials indicated that no significant differences could be observed. 4. A measure of the extent of reaction could be obtained if the a-hy- droxymethyl ketone had some functional group which could be easily determined. A callus sample that had been treated with p-bromophen- acyl alcohol (and was deeply colored) was submitted to halogen analysis along with a control sample of callus. No differences were obtained between samples. Samples of hair treated with p-bromophenacyl alcohol were also