REACTION OF a-HYDROXYMETHYL KETONES 781 analyzed for bromine. The amount of bromine in these samples was too low to be detected. 5. Bovine albumin is a water-soluble, ethanol-insoluble protein. Treatment of bovine albumin with absolute ethanol, if the times are not unduly prolonged, does not alter its water solubility. However, it was observed that, when a suspension of bovine albumin, absolute ethanol and either DHA, phenacyl alcohol, p-bromophenacyl alcohol, or p-nitro- phenacyl alcohol was shaken overnight, the bovine albumin became slightly colored and was converted into a water-insoluble form. When p-dimethylaminophenacyl alcohol was used, the bovine albumin was not converted into a water-insoluble form, and no color change in the al- bumin was noted. DISCUSSION The reaction of callus and amino acids with a-hydroxymethyl ketones to produce colored products appears to be a general one, and the rate of reaction appears to be related to the concentration of reagents. In addition, there is a suggestion that the reaction is enhanced (as judged by the intensity of the colors produced) if electron withdrawing groups are attached to the a-hydroxymethyl ketone. Thus, the order of de- creasing color intensity of treated callus was p-nitrophenacyl alcohol, p-bromophenacyl alcohol, phenacyl alcohol and p-hydroxyphenacyl alcohol. In addition, it was noted that of the a-hydroxymethyl ketones reacted with bovine albumin only p-dimethyl amino phenacyl alcohol was without effect on its color and solubility. If the color formations were related to a Maillard type of reaction (8) (as suggested by the fact that removal of amino groups with formaldehyde blocked the reaction), such an activating effect would be predicted for electronegative groups. Comparisons of the effects of amino acid structure on the rate of reaction are indicated in Table II. Thus, increasing the chain length by one carbon atom (glycine vs. alpha-alanine, aspartic acid vs. glutamic acid) has little effect on the rate. On the other hand, comparison of a- vs. •-alanine shows the latter to be substantially more reactive. Thus, compounds with more basic nitrogen groups appear to produce a color reaction much sooner. This is also seen in the case of arginine, which is a relatively rapid reactor, and in the cases of the dicarboxylic acids, which are relatively slow reactors. The failure of the various analytical schemes to detect the presence of the reacted a-hydroxymethyl ketones on callus suggests that, although

782 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS in some cases relatively intense color was produced, very little material had actually reacted with the callus. It was observed, however, that in all cases where colored products were formed it was impossible to remove the color from the keratin by simple washing procedures. (Received July 16, 1965) (t) (2) (a) (4) (a) (6) (7) (8) (9) (lO) (11) REFERENCES Goldman, L., et al., .1. Invest. Dermatol., 35, 161 (1960). Wittgenstein, E., and Berry, H., Ibid., 36,283 (1961). Idem, Science, 132,894 (1960). Flesch, P., and Esoda, E. C. J., Proc. Sci. Sect. Toilet Goods Assoc., 34, 53 (1960). Maibach, H. I., and Kligman, A.M., A .M.A. Arch. Dermatol., 82,505 (1960). Lento, H. G., et al., Food Research, 25,750 (1960). Idem, Food Research, 25,757 (1960). Ellis, G. P., Adv. Carbohydrate Chem., 14, 63 (1959). Richards, E. L., Biochem. J., 64,639 (1956). McWeeny, D. J., and Bruton, H. S., Nature, 196, 40 (1962). Burton, H. S., et al., Ibid., 196,948 (1962).