From hypervalent xenon difluoride and aryliodine(III) difluorides to onium salts: Scope and limitation of acidic fluoroorganic reagents in the synthesis of fluoroorgano xenon(II) and iodine(III) onium salts

Fluorinated organodifluoroboranes R_fBF₂ are in general suitable reagents to transform XeF₂ and RIF₂ into the corresponding onium tetrafluoroborate salts [R_fXe][BF₄] and [R(R_f)I][BF₄], respectively. (4-C₅F₄N)BF₂ and trans-CF₃CFCFBF₂ which represent boranes of high acidity form no Xe-C onium salts in reactions with XeF₂ but give the desired iodonium salts with RIF₂ (R = C₆F₅, o-, m-, p-C₆FH₄). The reaction of (4-C₅F₄N)BF₂ with XeF₂ ends with a XeF₂-borane adduct. C₆F₅Xe(4-C₅F₄N), the first Xe-(4-C₅F₄N) compound, was obtained when C₆F₅XeF was reacted with Cd(4-C₅F₄N)₂. We describe the synthesis of (4-C₅F₄N)IF₂ and reactions of (4-C₅F₄N)IF₂ and C₆F₅IF₂ with (4-C₅F₄N)BF₂. Analogous to [(4-C₅F₄N)₂I][BF₄] and [C₆F₅(4-C₅F₄N)I][BF₄] aryl(perfluoroalkenyl)iodonium salts [R(R′)I][BF₄] were obtained from RIF₂ (R = C₆F₅, o-, m-, p-C₆FH₄) and R′BF₂ (R′ = trans-CF₃CFCF, CF₂CF). The gas phase fluoride affinities pF⁻ of selected fluoroorganodifluoroboranes R_fBF₂ and their hydrocarbon analogs are calculated (B3LYP/6-31+G^*) and discussed with respect to their potential to introduce R_f-groups into hypervalent EF₂ bonds. Four aspects which influence the transformation of hypervalent EF₂ bonds (E = Xe, R′I) under the action of Lewis acidic reagents RAF_n−1 (A = B, P; n = 3, 5) into the corresponding [RE][AF_n+1] salts are presented and the important role of the acidity is emphasized. Fluoride affinities may help to plan the introduction of organo groups into EF₂ moieties and to expand the types of acidic reagents. Thus C₆H₅PF₄ with a pF⁻ value comparable to that of R_fBF₂ compounds is able to introduce the C₆H₅ group into RIF₂ (R = C₆F₅, p-C₆FH₄).     

Synthesis,Characterization, In Vitro Anticancer Potentiality,and Antimicrobial Activities of Novel Peptide–Glycyrrhetinic-Acid-Based Derivatives

Glycyrrhetinic acid (GA) is one of many interesting pentacyclic triterpenoids showing significant anticancer activity by triggering apoptosis in tumor cell lines. This study deals with the design and synthesis of new glycyrrhetinic acid (GA)–amino acid peptides and peptide ester derivatives. The structures of the new derivatives were established through various spectral and microanalytical data. The novel compounds were screened for their in vitro cytotoxic activity. The evaluation results showed that the new peptides produced promising cytotoxic activity against the human breast MCF-7 cancer cell line while comparing to doxorubicin. On the other hand, only compounds 3, 5, and 7 produced potent activity against human colon HCT-116 cancer cell line. The human liver cancer (HepG-2) cell line represented a higher sensitivity to peptide 7 (IC₅₀; 3.30 μg/mL), while it appeared insensitive to the rest of the tested peptides. Furthermore, compounds 1, 3, and 5 exhibited a promising safety profile against human normal skin fibroblasts cell line BJ-1. In order to investigate the mode of action, compound 5 was selected as a representative example to study its in vitro effect against the apoptotic parameters and Bax/BCL-2/p53/caspase-7/caspase-3/tubulin, and DNA fragmentation to investigate beta (TUBb). Additionally, all the new analogues were subjected to antimicrobial assay against a panel of Gram-positive and Gram-negative bacteria and the yeast candida Albicans. All the tested GA analogues 1–8 exhibited more antibacterial effect against Micrococcus Luteus than gentamicin, but they exhibited moderate antimicrobial activity against the tested bacterial and yeast strains. Molecular docking studies were also simulated for compound 5 to give better rationalization and put insight to the features of its structure.     

Optical solitons and complexitons of the Schrödinger–Hirota equation

The Schrödinger–Hirota equation governs the propagation of optical solitons in a dispersive optical fiber. In this paper, this equation will be solved by the ansatz method for bright and dark 1-soliton solution. The power law nonlinearity will be assumed. By using the tanh method, some additional solutions will be derived. Finally, the numerical simulations will be given.     

Holography based super resolution

This paper describes the simulation of a simple technique of superresolution based on holographic imaging in spectral domain. The input beam assembly containing 25 optical fibers with different orientations and positions is placed to illuminate the object in the 4f optical system. The position and orientation of each fiber is calculated with respect to the central fiber in the array. The positions and orientations of the fibers are related to the shift of object spectrum at aperture plane. During the imaging process each fiber is operated once in the whole procedure to illuminate the input object transparency which gives shift to the object spectrum in the spectral domain. This shift of the spectrum is equal to the integral multiple of the pass band aperture width. During the operation of single fiber (ON-state) all other fibers are in OFF-state at that time. The hologram recorded by each fiber at the CCD plane is stored in computer memory. At the end of illumination process total 25 holograms are recorded by the whole fiber array and by applying some post processing and specific algorithm single super resolved image is obtained. The superresolved image is five times better than the band-limited image. The work is demonstrated using computer simulation only.     

Supercontinuum generation at 1.55μm using highly nonlinear photonic crystal fiber for telecommunication and medical applications

In this paper, we present a theoretical calculation of a highly nonlinear germanium (Ge) doped photonic crystal fiber with all-normal group velocity dispersion to design a supercontinuum (SC) light source at 1.55 μm. By doping 3% higher refractive index Ge inside the host silica, the nonlinear coefficient is increased to a value as large as 60.5 W^?1 km^?1 at 1.55 μm. A 10 dB bandwidth of a 120 nm SC spectrum for a 2.5 ps input optical pulse and a 10 dB bandwidth of a 190 nm SC spectrum for a 1.0 ps input optical pulse have been found using the same fiber length of 200m and input optical power of 18 W. The coherent lengths of the generated SC light sources are found to be 8.8 μm for a 2.5 ps input optical pulse and 5.6 μm for a 1.0 ps input optical pulse. Therefore, the highest longitudinal resolution at 1.55 μm is found to be about 4.0 μm for biological tissues.     

New Quinoxaline-Based Derivatives as PARP-1 Inhibitors: Design,Synthesis, Antiproliferative,and Computational Studies

Herein, 2,3-dioxo-1,2,3,4-tetrahydroquinoxaline was used as a bio-isosteric scaffold to the phthalazinone motif of the standard drug Olaparib to design and synthesize new derivatives of potential PARP-1 inhibitory activity using the 6-sulfonohydrazide analog 3 as the key intermediate. Although the new compounds represented the PARP-1 suppression impact of IC₅₀ values in the nanomolar range, compounds 8a, 5 were the most promising suppressors, producing IC₅₀ values of 2.31 and 3.05 nM compared to Olaparib with IC₅₀ of 4.40 nM. Compounds 4, 10b, and 11b showed a mild decrease in the potency of the IC₅₀ range of 6.35–8.73 nM. Furthermore, compounds 4, 5, 8a, 10b, and 11b were evaluated as in vitro antiproliferative agents against the mutant BRCA1 (MDA-MB-436, breast cancer) compared to Olaparib as a positive control. Compound 5 exhibited the most significant potency of IC₅₀; 2.57 µM, whereas the IC₅₀ value of Olaparib was 8.90 µM. In addition, the examined derivatives displayed a promising safety profile against the normal WI-38 cell line. Cell cycle, apoptosis, and autophagy analyses were carried out in the MDA-MB-436 cell line for compound 5, which exhibited cell growth arrest at the G2/M phase, in addition to induction of programmed apoptosis and an increase in the autophagic process. Molecular docking of the compounds 4, 5, 8a, 10b, and 11b into the active site of PARP-1 was carried out to determine their modes of interaction. In addition, an in silico ADMET study was performed. The results evidenced that compound 5 could serve as a new framework for discovering new potent anticancer agents targeting the PARP-1 enzyme.     

Front Cover: Deoxygenative Intramolecular Minisci-Type Reaction to Access Fused Heterocyclic Scaffolds (Eur. J. Org. Chem. 7/2023)

Herein, we present a straightforward strategy for the synthesis of fused heterocycles through a deoxygenative, intramolecular Minisci-type reaction. This approach grants access to complex polycyclic scaffolds in three steps from readily available starting materials, such as chlorinated heteroarenes and 1,3-diols. The use of saccharide derivatives as the starting 1,3-diol motif allows for the synthesis of novel heterocyclic scaffolds with excellent diastereoselectivity and formal retention of configuration at the newly formed C−C bond.     

Dual-band detection based on metamaterial sensor at terahertz frequency

Optical Review - This work reported a novel terahertz sensor based on metamaterial absorber. The proposed structure is composed of rectangular metallic resonator made of gold placed above on...     

ChemInform Abstract: Microstructural Evolution During the Sintering of Nanostructured Ceramic Oxides.

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