Identification of a Genetic Factor Required for High γ‑Isoform Concentration in Rice Vitamin E

The γ-isoforms of tocopherols (Tc) and tocotrienols (T3) possess high biological activities in comparison to the α-isoforms. The concentrations of Tc and T3 isoforms in rice (Oriza sativa) was cultivar-dependent. Using chromosome segment substitution lines (CSSLs) and near isogenic lines (NILs) of indica cultivar “Kasalath” in a japonica cultivar “Koshihikari” genetic background, the Kasalath genomic segment on chromosome 2 was determined to be responsible for the high γ-isoform concentration: γ-tocopherol methyltransferase (<i>γ-TMT</i>) was identified as a candidate gene. An amino acid substitution in the coding region and several nucleotide polymorphisms, including an insertion of 10 base pairs in the promoter region, were identified. Gene expression analysis revealed that low expression levels of the <i>γ-TMT</i> gene in Kasalath were not associated with the γ-isoform concentration. Genetic variations in the coding region of the <i>γ-TMT</i> gene may play a major role in determining the γ-isoform concentration. This information could be used to breed rice with a high γ-isoform content

Total Synthesis and Structural Determination of XR774, a Tyrosine Kinase Inhibitor

Total synthesis and structural determination of XR774 has been accomplished. The benzo­[<i>j</i>]­fluoranthene skeleton has been constructed by regioselective coupling between tetraline <b>3</b> and tetralone <b>4</b> successively followed by the sequential transformation including the Birch reduction to prepare allylic alcohol, simultaneous bromination of vinylic and aromatic moieties, and the nickel-mediated intramolecular coupling reaction. The optical resolution of racemic <b>17</b> led to the first total synthesis of (−)-XR774

Remote Asymmetric Bromination Reaction with Vinylketene Silyl <i>N</i>,<i>O</i>‑Acetal and Its Application to Total Synthesis of Pellasoren A

Stereoselective bromination of the <i>E</i>,<i>E</i>-vinylketene silyl <i>N</i>,<i>O</i>-acetal possessing a chiral auxiliary has been achieved and applied to introduction of heteroatom at γ-position of α,β-unsaturated imide. The reactions proceeded in high stereoselectivity. Total synthesis of pellasoren A, an antitumor propionate from the myxobacteriun <i>Sorangium cellulosum</i>, has been accomplished in short steps by this methodology and our method of reduced polypropionate synthesis

Total Synthesis and Structural Determination of XR774, a Tyrosine Kinase Inhibitor

Total synthesis and structural determination of XR774 has been accomplished. The benzo­[<i>j</i>]­fluoranthene skeleton has been constructed by regioselective coupling between tetraline <b>3</b> and tetralone <b>4</b> successively followed by the sequential transformation including the Birch reduction to prepare allylic alcohol, simultaneous bromination of vinylic and aromatic moieties, and the nickel-mediated intramolecular coupling reaction. The optical resolution of racemic <b>17</b> led to the first total synthesis of (−)-XR774