Research Of Thio Active Component In Hair Care Cosmetics

The synthesis of the thio-modified hair humectant——N-thioacetyl-DL-serine and the thio-modified dye——thio-modified D&C Red No.17,as well as the applications were studied in this paper.N-thioacetyl-DL-serine was prepared from N-chloroacetyl-DL-serine and sodium hydrosulfide in the solvent of absolute alcohol.The chemical structure of the product was confirmed by IR,HPLC and HPLC-MS analysis.The optimal conditions of the reaction were,reaction temperature,40℃,reaction time,15 min,molar ratio of N-chloroacetyl-DL-serine to sodium hydrosulfide,1 :4,product yield,21.5 %.N-chloroacetyl-DL-serine was synthesized by Activated ester method and Schotten-Baumann reaction.The colorless crystal was identified by m.p.,IR,MS and 1HNMR.The moisturizing effect of N-thioacetyl-DL-serine was studied.Compared to other normal humectants,N-thioacetyl-DL-serine could be used as a broad,lasting humectant moisturize because of its moisturizing stability in different moisture level . At the same time , the moisturizing effect after hair treated with N-thioacetyl-DL-serine whether thioglycollic acid was added in or not was studied.N-thioacetyl-DL-serine could be used in high-grade hair care products because the moisturizing effect of it was more better than serine under the help of thioglycollic acid.And the DSC analysis showed that N-thioacetyl-DL-serine could be linked to hair by changing the Sulfur-Sulfur bonds with the cystine in the hair.Imitating the mechanism of the thio-modified humectant,the thio-modified D&C Red No.17 was prepared from sodium hydrosulfide and the intermediate,which was synthesized from D&C Red No.17 and 2-(chloromethyl)oxirane.The chemical structure of the product was identified by IR and HPLC-MS analysis.The hair dye effect of D&C Red No.17 and the thio-modified D&C Red No.17 was studied.The results showed that the thio-modified D&C Red No.17 had good hair dye effect when D&C Red No.17 couldn't dye hair and could be used in permanent hair dye formula.