Pierre Loti'nin yüzüncü doğum yıldönümü

Taha Toros Arşivi, Dosya Adı: Pierre Lotiİstanbul Kalkınma Ajansı (TR10/14/YEN/0033) İstanbul Development Agency (TR10/14/YEN/0033

Supplemental Material - Ethical issues in the operating room: A scoping review

Supplemental Material for Ethical issues in the operating room: A scoping review by Heejung Jeon, Sanghee Kim, and Yuha Shon in Nursing Ethics</p

(<i>E</i>)- and (<i>Z</i>)‑Stereodefined Enol Sulfate Esters Derived from α‑Aryl Aldehydes: Stereocomplementary Synthesis of Styryl Sulfate Natural Products

A method for the stereoselective formation of enol sulfate esters from α-aryl aldehydes is described. This method involved the stereocontrolled enolization of a carbonyl group with DBU or <i>t</i>-BuOK followed by trapping with a reactive sulfuryl imidazolium salt, providing the corresponding styryl enol sulfate esters in good to excellent yields and stereoselectivities. This method was applied to the first total synthesis of the enol sulfate natural products in a stereocomplementary manner

Bimodal Calix[2]triazole[2]arene Fluorescent Ionophore

Pyrene-appended calix[2]triazole[2]arene capable of bimodal sensing has been synthesized. Upon addition of Zn²⁺ (or Cd²⁺), it selectively exhibits an enhanced monomeric emission (∼13–20-fold) over other metal ions. On the other hand, it displays excellent selectivity for Fe²⁺ over other metal ions (even over Fe³⁺) from the angle of excimeric emissions (10-fold enhancement). Density Functional Theory (DFT) based theoretical calculations distinguished the bimodal activity of the probe and supported the experimental observations

Regiodivergent Halogenation of (<i>E</i>)‑β-Chlorovinyl Ketones via Soft α‑Vinyl Enolization Strategy

The soft α-vinyl enolization of (<i>E</i>)-β-chlorovinyl ketones was investigated in the presence of various halogen electrophiles. Depending on the nature of halogen electrophiles, the selective formation of three products, namely α,α-dichloropropargyl ketones, α,γ-dihaloallenyl ketones, and 3-halofurans, was observed. The observed regiodivergent nucleophilic pathways of (<i>E</i>)-β-chlorovinyl ketones demonstrate the diversity-oriented synthesis strategy in which the nucleophilic reactivity of (<i>E</i>)-β-chlorovinyl ketones can be selectively modulated by the choice of suitable hard and soft electrophiles

Synthesis of Quinolizinium-Type Heteroaromatics via a Carbene Intermediate

An efficient synthesis of quinolizinium-type heteroaromatics by Pt­(II)-catalyzed cyclization of 2-arylpyridine propargyl alcohol has been developed. The presence of a protic acid is crucial for the success of the reaction. Mechanistic studies disclosed that the reaction proceeds via a platinum–carbene intermediate. Additionally, the fluorescence properties of the synthesized heteroaromatics were investigated to provide perspectives for potential applications

Asymmetric Total Synthesis of Lepadiformine C Using Memory of Chirality in an Intramolecular Ester Enolate Michael Addition

The asymmetric synthesis of lepadiformine C was achieved using d-proline as the only chiral source. The synthetic strategy features the use of the principle of “memory of chirality” in an intramolecular Michael addition to construct the bicyclic intermediate without the aid of external chiral sources. A brief mechanistic rationale is presented to account for the stereochemical outcome

DataSheet1_Annulation of O-silyl N,O-ketene acetals with alkynes for the synthesis of dihydropyridinones and its application in concise total synthesis of phenanthroindolizidine alkaloids.pdf

The formation of N-heterocycles with multiple substituents is important in organic synthesis. Herein, we report a novel method for the construction of functionalized dihydropyridinone rings through the annulation of an amide α-carbon with a tethered alkyne moiety. The reaction of the amide with the alkyne was achieved via O-silyl N,O-ketene acetal formation and silver-mediated addition. Furthermore, the developed method was applied for the total synthesis of phenanthroindolizidine and phenanthroquinolizidine alkaloids. By varying the coupling partners, a concise and collective total synthesis of these alkaloids was achieved.</p

Enzymatic modification by point mutation and functional analysis of an omega-6 fatty acid desaturase from Arctic <i>Chlamydomonas</i> sp.

<p>Arctic <i>Chlamydomonas</i> sp. is a dominant microalgal strain in cold or frozen freshwater in the Arctic region. The full-length open reading frame of the omega-6 fatty acid desaturase gene (AChFAD6) was obtained from the transcriptomic database of Arctic <i>Chlamydomonas</i> sp. from the KOPRI culture collection of polar micro-organisms. Amino acid sequence analysis indicated the presence of three conserved histidine-rich segments as unique characteristics of omega-6 fatty acid desaturases, and three transmembrane regions transported to plastidic membranes by chloroplast transit peptides in the N-terminal region. The AChFAD6 desaturase activity was examined by expressing wild-type and V254A mutant (Mut-AChFAD6) heterologous recombinant proteins. Quantitative gas chromatography indicated that the concentration of linoleic acids in <i>AChFAD6</i>-transformed cells increased more than 3-fold [6.73 ± 0.13 mg g⁻¹ dry cell weight (DCW)] compared with cells transformed with vector alone. In contrast, transformation with Mut-<i>AChFAD6</i> increased the concentration of oleic acid to 9.23 ± 0.18 mg g⁻¹ DCW, indicating a change in enzymatic activity to mimic that of stearoyl-CoA desaturase. These results demonstrate that AChFAD6 of Arctic <i>Chlamydomonas</i> sp. increases membrane fluidity by enhancing denaturation of C18 fatty acids and facilitates production of large quantities of linoleic fatty acids in prokaryotic expression systems.</p

Design, Synthesis, and Biological Activity of Sulfonamide Analogues of Antofine and Cryptopleurine as Potent and Orally Active Antitumor Agents

Due to their profound antiproliferative activity and unique mode of action, phenanthro­indolizidine and phenanthro­quinolizidine alkaloids, represented by antofine and cryptopleurine, have attracted attention recently as potential therapeutic agents. We have designed, synthesized, and evaluated the methanesulfonamide analogues of these natural alkaloids with the hope of improving their druglikeness. The analogues showed enhanced growth inhibition of human cancer cells compared with the parent natural products. In particular, a methanesulfonamide analogue of cryptopleurine (<b>5b</b>) exhibited improved bioavailability and significant antitumor activity, which suggests that <b>5b</b> is a promising new anticancer agent. Our studies suggest that the inhibition of cancer cell growth by <b>5b</b> is associated with the induction of G0/G1 cell cycle arrest via nicotinamide <i>N</i>-methyltransferase-dependent JNK activation in Caki-1 renal cancer cells. In addition, compound <b>5b</b> significantly inhibited the migration and invasion of Caki-1 cancer cells by modulating the p38 MAPK signaling pathway