Didier Semeria

Synthesis of 2-N-oleoylamino-octadecane-1,3-diol: a new ceramide highly effective for the treatment of skin and hair.

2‐N‐Oleoylamino‐octadecane‐1,3‐diol is a new synthetic ceramide. The process enables a four‐step preparation of 2‐amino‐octadecane‐1,3‐diol (D,L‐erythro/threo) and a five‐step synthesis of 2‐N‐oleoylamino‐octadecane‐1,3‐diol (D,L‐erythro/threo). The latter compound is related to ceramide 2 according to the classification of Downing. This route of synthesis is rapid, reproducible and uses low‐cost starting materials. The new ceramide was analysed as follows: 1H, 13C, 15N NMR spectra afforded an unambiguous characterization of the structure; additionally, these three methods identified the threo and erythro isomers. 1H and 13C NMR permitted the measurement of the threo/erythro ratio (26.6/73.4 and 25.5/74.5, respectively). Chemical ionization mass spectrometry confirmed the expected mass of the pseudo‐molecular ion (m/z= 566.5: [M + H]+) as well as the presence of different chain lengths other than the oleic moiety due to the fatty acid composition of the technical grade oleic acid used for the synthesis. Capillary gas chromatography measured the threo/erythro ratio (23.5/76.5) which agrees with the 1H and 13C NMR data. Moreover, this method afforded the relative distribution of the different N‐acylated chains. The properties of the new synthetic ceramide for the treatment of skin and hair were mainly assessed by two in vitro methods. The first measured the flux of water through lipid‐extracted stratum corneum. The described ceramide showed high efficacy in decreasing water loss. The second recorded the friction coefficient of different types of hair: virgin, permanent‐waved, and bleached. Treatment by the ceramide led to a strong decrease in this coefficient. This was particularly observed on unrinsed hair. These findings suggest two potential fields of application and beneficial contribution for the new ceramide: repairing the barrier to transepidermal water loss, and improving the surface properties of hair.

Synthesis of 1,2:5,6-di-O-isopropylidene-D-glucofuranos-3-yl and 1,2:3,4-di-O-isopropylidene-D-galactopyranos-6-yl-(N-diphenylmethylene) glycinates

Abstract 1,2:3,4-di-O-isopropylidene-D-galactopyranos-6-yl-(N-diphenylmethylene)-glycinate 3 , was prepared via a trans-esterification process from ethyl (N-diphenylmethylene)-glycinate and 1,2:5,6-di-O-isopropylidene-D-glucofuranos-3-yl-(N-diphenylmethylene) glycinate 9 , via a trans-imination reaction from 1,2:5,6-di-O-isopropylidene-D-glucofuranos-3-yl glycinate 6 and diphenyl-ketiminium chloride.