10.1021/jo0206824
The research focuses on the total syntheses of symbioramide derivatives, which are bioactive compounds with potential antileukemic properties, derived from L-serine. The study involves the preparation of various symbioramide derivatives, including (2S,3R,2′R,3′E)-N-(2′-hydroxy-3′-octadecenoyl)-dihydrosphingosine (1a) and its diastereomers (1b-d), by synthesizing the amino part (D-erythro-dihydrosphingosine) and acid parts ((2R,3E)-2-hydroxy-3-octadecenoic acid and its isomers) from L-serine and D-mannitol, respectively. The synthesized compounds were then assessed for their antileukemic activities against HL-60 and L-1210 cell lines using the MTT assay. The experiments utilized various reagents, protection and deprotection strategies, and purification techniques such as column chromatography. Analytical methods like specific rotation measurements, infrared spectroscopy (IR), nuclear magnetic resonance (NMR), and high-resolution mass spectrometry (HRMS) were employed to characterize the synthesized compounds and assess their structures and purities. The results indicated that all symbioramide derivatives showed moderate antileukemic activities against L-1210 cells, with compound 1d being the most effective.
10.1016/S0040-4020(01)92870-4
The study focuses on the isolation and structural elucidation of three sesquiterpene oxides, namely liguloxide (III), liguloxidol (IV), and liguloxidol acetate (V), from the aerial parts of Ligularia turczaninowii. The researchers used various chemical reactions and analytical techniques to determine the structure and absolute configuration of these compounds. They employed microbial hydroxylation to introduce hydroxyl groups into the molecule, aiding in structural determination. Liguloxide was found to be a guaiane sesquiterpene with a ditertiary ether bridge, while liguloxidol and liguloxidol acetate were shown to have the same framework with an additional hydroxyl group. The study also involved the preparation of various epimers and the use of osmium tetroxide oxidation, Jones oxidation, and other reactions to confirm the structure and configuration of these compounds. The absolute configuration was clarified by correlating liguloxide with the known compound guaioxide (XIX) through epimerization of the C-4 methyl group and microbial hydroxylation.
