A few naturally occurring prenyl- and renyloxycoumarins and several new related synthetic derivatives were evaluated as inhibitors of squalene-hopene cyclase (SHC), a useful model enzyme, to predict their interactions with oxidosqualene cyclase (OSC). Umbelliprenin-10',11'-monoepoxide (IC50 2.5 muM) and the corresponding 6',7'-10', 11' diepoxide (IC50 1.5 muM) were the most active enzyme inhibitors. (C) 2004 Elsevier Ltd. All rights reserved.
Selective Monocyclization of Epoxy Terpenoids Promoted by Zeolite NaY. A Short Biomimetic Synthesis of Elegansidiol and Farnesiferols B−D
Epoxy terpenes cyclize readily, by confinement within zeolite NaY, to form exomethylenic cyclohexanols as the major products. The selective monocyclization of 10,11-epoxyfarnesyl acetate within NaY provides a short and efficient biomimetic route to (+/-)-elengasidiol and (+/-)-farnesiferols B-D.
Chemo-enzymatic enantio-convergent asymmetric synthesis of (R)-(+)-Marmin
作者:Klaus Edegger、Sandra F Mayer、Andreas Steinreiber、Kurt Faber
DOI:10.1016/j.tet.2003.10.106
日期:2004.1
Asymmetric biohydrolysis of trisubstituted terpenoid oxiranes (rac-1a–rac-3a) was accomplished by employing the epoxide hydrolase activity Rhodococcus and Streptomyces spp. Depending on the biocatalyst, the biohydrolysis proceeded in an enantio-convergent fashion and gave the corresponding vic-diols in up to 97% ee at conversions beyond the 50%-threshold. In order to avoid a depletion of the ee of