Enantioselective C–C Bond Formation during the Oxidation of 5‑Phenylpent-2-enyl Carboxylates with Hypervalent Iodine(III)

The oxidation of (5-acyloxypent-3-enyl)­benzene with hypervalent iodine­(III) afforded 2-oxy-1-(oxymethyl)­tetrahydronaphthalene under metal-free conditions. The acyloxy group may nucleophilically participate in the oxidative cyclization. A lactate-based chiral hypervalent iodine afforded an enantioselective variant of oxyarylation with up to 89% ee

A Series of Two Oxidation Reactions of <i>ortho</i>-Alkenylbenzamide with Hypervalent Iodine(III): A Concise Entry into (3<i>R</i>,4<i>R</i>)‑4-Hydroxymellein and (3<i>R</i>,4<i>R</i>)‑4-Hydroxy-6-methoxymellein

A sequence of oxidation reactions of alkenamides with hypervalent iodine is described. Oxidation of <i>ortho</i>-alkenylbenzamide substrates selectively gave isochroman-1-imine products. The products underwent further oxidation in the presence of a Pd salt catalyst leading to regioselective C–H acetoxylation at the 8-position. A series of oxidations was applied to the crucial steps of asymmetric synthesis of 4-hydroxymellein derivatives

A Series of Two Oxidation Reactions of <i>ortho</i>-Alkenylbenzamide with Hypervalent Iodine(III): A Concise Entry into (3<i>R</i>,4<i>R</i>)‑4-Hydroxymellein and (3<i>R</i>,4<i>R</i>)‑4-Hydroxy-6-methoxymellein

A sequence of oxidation reactions of alkenamides with hypervalent iodine is described. Oxidation of <i>ortho</i>-alkenylbenzamide substrates selectively gave isochroman-1-imine products. The products underwent further oxidation in the presence of a Pd salt catalyst leading to regioselective C–H acetoxylation at the 8-position. A series of oxidations was applied to the crucial steps of asymmetric synthesis of 4-hydroxymellein derivatives

Theoretical Insight into Stereoselective Reaction Mechanisms of 2,4-Pentanediol-Tethered Ketene-Olefin [2 + 2] Cycloaddition

We report ab initio molecular dynamics calculations based on density functional theory performed on an intramolecular [2 + 2] cycloaddition between ketene and olefin linked with a 2,4-pentanediol (PD) tether. We find that the encounter of the ketene and olefin moieties could be prearranged in the thermal equilibrated state before the cycloaddition. The reaction mechanism is found to be stepwise, similar to that of intermolecular ketene [2 + 2] cycloadditions with ordinary alkenes. A distinct feature of the reaction pathway for a major diastereoisomer is a differential activation free energy of about 1.5 kcal/mol, including 2.8 kcal/mol as the differential activation entropy, with a transition state consisting of a flexible nine-membered ring in the olefin-PD-ketene moiety. This theoretical study provides a reasonable explanation for the strict stereocontrollability of the PD-tethered ketene-olefin cycloaddition, irrespective of reaction types or conditions

Asymmetric Synthesis of 4,8-Dihydroxyisochroman-1-one Polyketide Metabolites Using Chiral Hypervalent Iodine(III)

Stereoselective oxylactonization of <i>ortho</i>-alkenylbenzoate with chiral hypervalent iodine is applied to the asymmetric synthesis of 4-oxyisochroman-1-one polyketide metabolites including 4-hydroxymellein (<b>1</b>), a derivative of fusarentin <b>2</b>, monocerin (<b>3</b>), and an epimer of monocerin <i>epi</i>-<b>3</b>

Stereochemical assignment of the unique electron acceptor 5′-hydroxyphylloquinone, a polar analog of vitamin K₁ in photosystem I

<p>A unique electron-accepting analog of vitamin K₁ found in photosystem I in several species of oxygenic photosynthetic microorganisms was confirmed to be 5′-hydroxyphylloquinone (<b>1</b>) through stereo-uncontrolled synthesis. Furthermore, the stereochemistry of <b>1</b> obtained from <i>Synechococcus</i> sp. PCC 7942 was assigned to be 5′<i>S</i> using proline-catalyzed stereocontrolled reactions.</p> <p>Polar vitamin K₁ (<b>1</b>) was synthesized. Stereochemistry of natural <b>1</b> was determined to be (5′<i>S</i>) after a derivation, where the same derivative was also synthesized.</p

Penetration of pierisin-1 through parasitoid surfaces.

<p>A–F: Each stage of parasitoids was cultured with HiLyte dye-labeled pierisin-1 (red) for 24 h, and then labeled with STYO-16 Live-Cell Nucleic Acid Stain (green). CV, caudal vesicle. Arrows indicate surface layer of caudal vesicles. Apoptosis was observed in <i>G. pallipes</i> larvae (arrow heads). Parasitoid eggs and larvae were treated with Hilyte-labeled pierisin-1 at 10 µg/ml in the medium. The numbers of early stage eggs, late stage eggs, larvae and larvae without surface layer for <i>G. pallipes</i> and <i>C. glomerata</i> used for analysis were three to five. G: Incorporation of pierisin-1 at 100 µg/ml in the caudal vesicle cells of <i>C. glomerata</i> larvae after removal of the surface layer. The arrow indicates the surface layer of the caudal vesicle. The anterior is on the left. Horizontal bars represent 50 µm.</p

Effects of pierisin-1 on parasitoid larvae.

<p>First instar larvae were cultured for 7 days in media with or without pierisin-1. A: Rates of damaged larvae of parasitic wasps. Green column, non-damage; yellow column, damaged; red column, death. <i>C. glomerata</i> larvae developed normally even in the presence of pierisin-1. Pierisin-1 treatment caused damage in larval bodies of non-habitual wasps. The numbers of larvae used for each treatment were 9 – 10 for <i>C. plutellae</i>, 11 – 16 for <i>C. kariyai</i>, 9 – 16 for <i>G. pallipes</i>, 11 – 25 for <i>C. glomerata.</i> B: Morphological analysis of cultured <i>C. kariyai.</i> a and b: Phase contrast microscope images of cultured <i>C. kariyai</i> larva with or without pierisin-1, respectively. c and d:. Transmission electron microscope (TEM) images of cross sections of their caudal vesicles. Apoptosis was observed in caudal vesicles on pierisin-1 treatment (arrowheads). Wasp larvae (n = 16) were treated with pierisin-1 at 10 µg/ml in the medium, and representative microscope images are shown. The anterior is on the left. Horizontal bars for phase contrast microscope represent 100 µm. Bars for TEM represent 1 µm.</p

Alteration of pierisin-1 expression by parasitization.

<p>A: mRNA levels were analyzed by real-time PCR after parasitization. Blue column, control: red column, <i>C. glomerata</i>; yellow column, <i>C. plutellae</i>. The numbers of mRNA molecules per one thousand 18 S ribosomal RNA were calculated. Values are the means ± S.Ds. of three analyses. The numbers of samples were five each at each time point. * p<0.001, when compared to control. B: Western blotting analysis of pierisin-1 protein in the hemolymph 1–12 h after parasitization by <i>C. glomerata</i> or <i>C. plutellae</i>. Amounts of full-length pierisin-1 (98-kDa) and 27-kDa N-terminal fragments of pierisin-1 were separately calculated using an imaging system, as mentioned in Materials and Methods. Circles control: squares, <i>C. glomerata</i>; triangles, <i>C. plutellae</i>. The numbers of samples were five each at each time point.▪ p<0.001, when compared to controls.</p

Loss of affects gene expression profile in a genome-wide manner in ES cells and liver cells-0

<p><b>Copyright information:</b></p><p>Taken from "Loss of affects gene expression profile in a genome-wide manner in ES cells and liver cells"</p><p>http://www.biomedcentral.com/1471-2164/8/227</p><p>BMC Genomics 2007;8():227-227.</p><p>Published online 10 Jul 2007</p><p>PMCID:PMC1959195.</p><p></p>nes (A) & (B). Horizontal and vertical axes represent expression levels normalized for an individual gene. Each point represents normalized expression data for an individual gene. The genes that showed standard deviation greater than 2.0 in the normalized data of both genotypes (A) were excluded and gene lists were constructed with < 0.05 (B). Fig. 1D–F in the original article [1] remains unchanged and is presented as (C) – (E), respectively