Abstract
The aim of this study is to prepare ceramide analogues as building block for synthesizing α-galactosyl ceramide analogue. As the starting material, L-serine was protected at its amino group with (Boc)2O. Without chromatography, N-Boc-serine was converted to the methyl ester derivative with diazomethane in ether. After protection of the amino and hydroxy groups with 2, 2-dimethoxy propane under reflux, the product: oxazolidine ester was treated with LiAlH4 to restore OH group. Following Swern oxidation, Garner’s aldehyde was obtained in total 38% yield via five steps. While Garner’s aldehyde was in hand, the subsequent Wittig reaction to introduce aliphatic chain at formyl group was forwarded. Dihydroxylation at this (Z)-form olefin under catalysis of OsO4 was employed to afford the syn addition product in 92% yield with 80% diaseteromeric excess. Following the removal of acetonide group with TFA, the phytosphingosine obtained was coupled with N-hydroxy- succinimide ester to introduce the amide-bond linkage. Afterwards, for obtaining satisfactory analytical spectra of the ceramide analogue, purification was prerequisite and this was achieved by protection of the hydroxy groups with acetic anhydride. As this ceramide analogue was in hand, the subsequent synthesis of alpha-galceramide and the relevant biological assay was performable. Further application of this compound includes drug delivery and cancer vaccine, in former case the self-formed liposome enwrapping the drug in aqueous solution served as the carrier.