| 摘要 |
PROBLEM TO BE SOLVED: To safely and simply obtain an optically active dihydroceramide useful as a cosmetic component in high purity and high yield. SOLUTION: A (2R,3R)-2-amino-3hydroxyalkanoic acid ester hydrochloride of formula I (R1 is a 9-21C alkyl; R2 is a 1-4C alkyl) is acylated with an acylating agent of the formula R3 -CO-X (R3 is a 9-19C alkyl or alkenyl; X is OH, a halogen or an ester-forming group) to afford a (2R,3R)-2-acylamino-3- hydroxyalkanoic acid ester, which is then reduced with sodium borohydride in an ether-based solvent to provide the objective (2S,3R)-2-acylaminoalkane-1, 3-diol of formula III. The compound of formula III exhibits moistening effect, beautifying and whitening effect and cell-activating effect on skin by adding the compound to a cosmetic and is useful as a skin preparation for external use for protecting drying of hair by hydrating cuticle of hair. |
