Synthesis of 4‑Halo-3(2<i>H</i>)‑furanones Using Intramolecular Cyclization of Sulfonium Salts

A simple and efficient synthesis of 4-halo-3­(2<i>H</i>)-furanones by halogenative intramolecular cyclization of sulfonium salts is described, which can expedite the production of a variety of 4-bromo- or 4-iodo-3­(2<i>H</i>)-furanones, useful synthetic building blocks, in good to high yield under mild conditions

Fundamental Semiconducting Properties of Perovskite Oxynitride SrNbO₂N: Epitaxial Growth and Characterization

We carried out theoretical calculations and demonstrated epitaxial growth of SrNbO₂N by RF reactive sputtering. The SrNbO₂N (001) epitaxial film on a SrTiO₃ (001) substrate had a single orientation and was of high crystalline quality. The film’s band gap was experimentally determined as being 1.81 eV using a spectroscopic ellipsometer. Its transition type was indirect. In Hall effect measurements, the SrNbO₂N film showed low Hall mobility despite our theoretical calculations showing the electron effective mass to be relatively low. Arrhenius plots of the Hall mobility and carrier concentration suggested the low mobility to result from conduction band bending due to the presence of grain boundaries

Helically Chiral 1‑Sulfur-Functionalized [6]Helicene: Synthesis, Optical Resolution, and Functionalization

The synthesis and optical resolution of helically chiral 5,6,9,10-tetrahydro-1-[6]­helicenethiol and its subsequent transformations to enantiopure 1-sulfur-functionalized [6]­helicenes are reported. A novel enantiopure [7]­thiahelicene having a thiophene ring at the terminal position of the [6]­helicene skeleton was synthesized

Creation of Readily Accessible and Orally Active Analogue of Cortistatin A

Syntheses of structurally simplified analogues of cortistatin A (<b>1</b>), a novel antiangiogenic steroidal alkaloid from Indonesian marine sponge, and their biological activities were investigated. The analogues were designed by considering the 3-D structure of <b>1</b>. Compound <b>30</b>, in which the isoquinoline moiety was appended to the planar tetracyclic core structure, showed potent antiproliferative activity against human umbilical vein endothelial cells (HUVECs) together with high selectivity and also showed <i>in vivo</i> antiangiogenic activity and significant antitumor effect by oral administration

Contribution of Cage-Shaped Structure of Physalins to Their Mode of Action in Inhibition of NF-κB Activation

A library of oxygenated natural steroids, including physalins, withanolides, and perulactones, coupled with the synthetic cage-shaped right-side structure of type B physalins, was constructed. SAR studies for inhibition of NF-κB activation showed the importance of both the B-ring and the oxygenated right-side partial structure. The 5β,6β-epoxy derivatives of both physalins and withanolides showed similar profiles of inhibition of NF-κB activation and appeared to act on NF-κB signaling via inhibition of phosphorylation and degradation of IκBα. In contrast, type B physalins with C5–C6 olefin functionality inhibited nuclear translocation and DNA binding of RelA/p50 protein dimer, which lie downstream of IκBα degradation, although withanolides having the same AB-ring functionality did not. These results indicated that the right-side partial structure of these steroids influences their mode of action

Template-Assisted and Self-Activating Clicked Peptide as a Synthetic Mimic of the SH2 Domain

A new synthetic strategy for obtaining artificial receptors that selectively regulate and/or control specific protein/protein interactions was developed based on the template-assisted and the self-activating click reaction applied to a combinatorial library. Synthetic mimics of the Grb2-SH2 domain, examined as a model case, selectively bound to a target signaling protein to induce cytotoxicity and inhibit tumor growth <i>in vivo</i>