Iron-catalyzed regio- and stereoselective substitution of gamma,delta-epoxy-alpha,beta-unsaturated esters and amides with Grignard reagents.

When gamma,delta-epoxy-alpha,beta-unsaturated esters or amides were treated with 2 equiv of Grignard reagents in the presence of 10-24 mol % FeCl(2), regio- and stereoselective substitution of the epoxide moiety with the Grignard reagent occurred to give exclusively delta-hydroxy-gamma-alkyl or aryl-alpha,beta-unsaturated esters or amides in good yields.

A chemical biosynthesis design for an antiatherosclerosis drug by acyclic tocopherol intermediate analogue based on "isoprenomics".

Phytyl quinols, namely acyclic tocopherols, are key intermediates of tocopherol biosynthesis, but their biological activities remain unclear. We therefore investigated the structure-activity relationship of phytyl quinols to apply a chemical biosynthesis design for an antiatherosclerosis drug based on isoprenomics. We have achieved the biosynthesis-oriented design and synthesis of alpha- (TX-2254) and beta-(TX-2247) phytyl quinol as an unnatural intermediate, other gamma- (TX-2242) and delta-(TX-2231) phytyl quinol as a natural one. Geometry optimization and Molecular orbital (MO) calculation of TX-2254 showed a unique right-angle structure; however, MO energy of TX-2254 and d-alpha-tocopherol were very similar. Radical reactivity of TX-2231 was equal to dl-alpha-tocopherol, whereas TX-2254, TX-2247, and TX-2231 showed lower reactivity than dl-alpha-tocopherol. All four phytyl quinols showed almost the same moderate inhibitory activity against low-density lipoprotein (LDL) oxidation instead of their different degree of C-methylation with character different from tocopherols. In vivo toxicities of phytyl quinols against chick embryo chorioallantoic membrane (CAM) vasculature were hardly observed. We proposed phytyl quinols were possible antioxidants in plants and animals, like vitamin E.

Artepillin C isoprenomics: design and synthesis of artepillin C isoprene analogues as lipid peroxidation inhibitor having low mitochondrial toxicity.

We designed and synthesized isoprene analogues of artepillin C, a major component of Brazilian propolis, and investigated the inhibitory activity on lipid peroxidation of rat liver mitochondria (RLM) and RLM toxicity based on isoprenomics. We succeeded in the synthesis of artepillin C isoprene analogues using regioselective prenylation within the range from 22% to 53% total yield. Reactivity of artepillin C and its isoprene analogues with ABTS (2,2'-Azinobis(3-ethylbenzothiazoline-6-sulfonate)) radical cations showed only a slight difference among the molecules. The isoprene side-chain elongation analogues of artepillin C showed almost the same inhibitory activity against RLM lipid peroxidation as artepillin C. Artepillin C and its isoprene analogues had very weak RLM uncoupling activity. Moreover, artepillin C and its isoprene analogues exhibited a lower inhibitory activity against adenosine 5'-triphosphate (ATP) synthesis by about two orders of magnitude than the effective inhibitory activity against RLM lipid peroxidation. From these results we conclude that artepillin C isoprene analogues could be potent lipid peroxidation inhibitors having low mitochondrial toxicity. We also conclude that elongation of the isoprene side chain of artepillin C to increase lipophilicity had little influence on the inhibitory activity toward RLM lipid peroxidation.