Helix-to-Disc Conversion of Thia[6]helicenes into Coronenes Facilitated by Sulfur Oxidation and Fluorination.

Helicenes, with their unique helical structures, have long captured the interest of synthetic chemists, not only as end products, but also as versatile platforms for further chemical transformations. However, transforming [6]helicene into planar coronene typically requires harsh conditions and poses significant challenges. Herein, we demonstrate that replacing the terminal benzene ring of [6]helicene with a thiophene ring enables its photochemical transformation into coronene. Sulfur oxidation of the thiophene ring enables the corresponding thermal transformation, and the terminal tetrafluorination of the opposite benzene ring further accelerates this process, yielding 1,2-difluorocoronene, as confirmed by X-ray crystallography. The transformation begins with an intramolecular Diels-Alder reaction, whose activation energy is significantly lowered by these structural changes. Our findings underscore the utility of strategic modifications such as sulfur oxidation and fluorination in promoting this "helix-to-disc" conversion and opening new avenues for synthesizing functional polycyclic aromatics.

A Wnt/ß-catenin signaling inhibitor, IMU1003, suppresses the emergence of osimertinib-resistant colonies from gefitinib-resistant non-small cell lung cancer cells.

Drug resistance has become a challenge in effective longterm molecular targeted therapy. Longterm non-small cell lung cancer (NSCLC) treatments with the first-generation epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) shorten the effective duration of the third-generation EGFR-TKI, osimertinib, via genetic or epigenetic mechanisms in addition to the gatekeeper mutation T790M. This study reproduced this persistence in vitro using gefitinib-resistant NSCLC PC-9 cells (GR cells) and revealed that pharmacological nuclear localization inhibition of ß-catenin suppressed the osimertinib resistance. Osimertinib effectively reduced GR cell survival but left significantly more resistant colonies than parental PC-9 cells. The nuclear fraction of ß-catenin was enriched in GR cells during acquisition of osimertinib resistance. A chemical nuclear localization inhibitor of ß-catenin, IMU1003, dramatically decreased the emergence of osimertinib-resistant colonies. Forced nuclear localization of ß-catenin reduced IMU1003 efficacy. Thus, suppression of the nuclear ß-catenin function may overcome the transgenerational EGFR-TKI-resistance.

Structure-Activity Relationship Study of N-Hydroxyphtalimide Derivatives for the Detection of Amines during Fmoc-Solid-Phase Peptide Synthesis.

Previously, we developed a method for the detection of unprotected amino groups based on their reversible reaction with N-hydroxyphthalimide (NHPI) to form intensely colored products, which can be useful when conducting solid-phase peptide synthesis. Here, we describe a structure-activity relationship study of NHPI derivatives to identify the derivative best suited for this method using a spectrophotometer toward the estimation of chemical yields. We found that the products resulting from the reaction of the derivative with an unprotected amino group were only intensely colored if the structure of the derivative incorporated an NHPI framework. We also prepared five peptides, including those containing N-methyl and D-amino acid, and Pro residues, using our reversible detection method to detect unprotected amino groups. The mechanism of the detection reaction was also studied by the structural analysis of the NHPI (1) and diisopropylamine complex and concluded to entail salt formation between the N-hydroxy group and amine.

A Diversifiable Synthetic Platform for the Discovery of New Carbasugar SGLT2 Inhibitors Using Azide-Alkyne Click Chemistry.

Sodium-glucose cotransporter 2 (SGLT2) inhibitors are clinically available to control blood glucose levels in diabetic patients via an insulin-independent mechanism. It was found that some carbasugar analogs of known SGLT2 inhibitors exert a high inhibiting ability toward SGLT2 and have a prolonged blood glucose lowering effect. In this study, we designed new candidates of carbasugar SGLT2 inhibitor that can be synthesized using copper-catalyzed azide-alkyne cycloaddition (CuAAC) into an aromatic ring, which is a part of the pharmacophore at the final stage in the synthetic protocol for the easier discovery of superior SGLT2 inhibitors. Based on the results of molecular docking studies, some selected compounds have been synthesized. Evaluation of these compounds using a cell-based assay revealed that the majority of these compounds had SGLT2 inhibitory activity in a dose-dependent manner. The SGLT2 inhibitory activity of 7b and 7c was almost equal to that of SGLT2 inhibitors in current use. Furthermore, molecular dynamics simulations also revealed that 7c is a promising novel SGLT2 inhibitor.

A Case of Mediastinal Tuberculous Lymphadenitis in a Chronic Dialysis Patient Diagnosed by Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration (EBUS-TBNA).

A 54-year-old woman on dialysis due to chronic renal failure had a fever lasting 2 weeks and was referred to a hospital. Non-enhanced CT and blood tests showed no remarkable findings. She was hospitalized and received an antibacterial drug. Although she was discharged after the fever subsided, she was hospitalized again due to a fever a few days later. A contrast-enhanced CT revealed mediastinal lymphadenopathy, and she was transferred to our hospital for a bronchoscopy. Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration (EBUS-TBNA) for subcarinal lymph nodes was performed in our hospital. The Polymerase Chain Reaction (PCR) test of the obtained specimen was positive for mycobacterium tuberculosis, and histologically, caseous granulomas were found in the specimen. She was diagnosed with mediastinal tuberculous lymphadenitis, and HREZ (isoniazid, rifampicin, ethambutol, and pyrazinamide) treatment was started. The fever subsided immediately, and she was discharged from our hospital 2 weeks after the initiation of treatment. Thereafter, she received treatment as an outpatient. Since the use of a contrast medium was complicated by dialysis, a non-enhanced CT was performed at first, and it was difficult to make a diagnosis from this. We report this as an informative case that could be diagnosed with EBUS-TBNA, which was easily performed on a patient weakened by prolonged fever and dialysis.

Skeletal Transformation Triggered by C-F Bond Activation after Photochemical Rearrangement of Fluorinated [7]Helicenes.

Tri- and tetra-fluorinated [7]helicenes are photolabile and undergo a double fluorine atom transfer. Herein, we show that the transferred product further undergoes a skeletal transformation on silica gel. The transformation begins with activation of the allylic C-F bond on the silanol surface. Then, the resulting carbocation readily undergoes a regioselective nucleophilic aromatic substitution with water, depending on the position of the fluorine substituents. Hexafluoro-2-propanol also activated the allylic C-F bond and acted as a nucleophile. These findings support the generation of a highly reactive cationic electrophilic intermediate in the successive transformations involving fluorine atoms.

Effect of the conformer distribution on the properties of amorphous organic semiconductor films for organic light-emitting diodes.

With the remarkable improvement in the electrical and optical properties of organic light-emitting diodes (OLEDs) in recent years, the details of the higher-order structure of vacuum-deposited amorphous organic films and its formation mechanism need to be understood. In particular, to clarify the effect of the higher-order structure on the film properties, it is necessary to analyze the molecular aggregation states in the vacuum-deposited amorphous films. Toward their deep understanding, the higher-order structure and film properties have often been discussed with relation to the surface diffusion and structural relaxation of the molecules immediately after deposition on the film surface. However, the effect of the variety of conformers, which is specific to amorphous organic materials, on the thermal and electrical properties of the films has not been deeply discussed. In this study, we focused on three structural isomers of OLED materials and discuss the effect of the conformer distribution on the molecular aggregation states and thermal and electrical properties of the vacuum-deposited films. From their comparison, we found that the properties of the film composed of a relatively small number of stable conformers are superior to those of the other two films composed of relatively large numbers of stable conformers. This superiority originates from formation of aggregates of the same conformer, which become the starting points for crystallization when the film is heated. Our detailed comparison and discussion focusing on the variety of conformers will lead to a deeper understanding of the molecular aggregation states and physical properties of amorphous organic films.

Novel Series of Mononuclear Aluminum Complexes for High-Performance Solution-Processed Organic Light-Emitting Devices.

Light metal complexes, such as lithium (Li), sodium (Na), magnesium (Mg), and aluminum (Al) complexes, are attractive candidates for the fabrication of thermally activated delayed fluorescent (TADF) materials. Nevertheless, mononuclear Al complexes with delayed fluorescence have not been developed so far. In this study, we successfully developed a novel series of highly luminescent Al complexes with two phenylacridine-modified asymmetric acetylacetonate-type ligands. These complexes exhibit high photoluminescence quantum yields (PLQYs) of up to 79 % in the solid state with a short delayed fluorescence lifetime of approximately 4 µs. Solution-processed organic light-emitting devices (OLEDs) using these Al complexes exhibit excellent performance with an external quantum efficiency of 17.5 % at 100 cd m-2 . This is the best performance in light metal-based TADF OLEDs reported so far. The results are expected to guide the advancement of the next-generation solid-state lighting technology.

Alkane Shape- and Size-Recognized Selective Vapor Sorption in "Channel-Like" Crystals Based on Thiacalixarene Assemblies.

Alkanes composed of C-C and C-H show a low electric polarization, and therefore, there is only very weak interaction between alkanes and adsorbents. Thus, it is difficult to separate a specific alkane from a mixture of alkanes by adsorption. Here, two activated "channel-like" crystals generated from brominated thiacalix[4]arene propyl ethers, which adopt 1,3-alternate and partial cone conformations, recognize specific alkane vapors depending on alkane-shape and -size, sorting in three-type alkane guests such as linear, branched, and cyclic alkanes. Two activated crystals, which are prepared by removal of solvent upon heating under reduced pressure, incorporate branched and/or cyclic alkane vapors by a unique "gate-opening" mechanism via a crystal transformation in the process. Linear alkane vapors do not trigger gate opening and are not taken up by the activated crystals. The shape and size molecular-recognition properties of the activated crystals promises considerable usefulness for the separation of linear, branched, and cyclic alkanes.

Alkane Shape- and Size-Recognized Selective Vapor Sorption in "Channel-Like" Crystals Based on Thiacalixarene Assemblies.

Invited for the cover of this issue is the group of Manabu Yamada at Akita University and colleagues from Yamagata University and Vellore Institute of Technology. The image depicts two activated "channel-like" crystals, effectively adsorb branched and cyclic alkanes from linear, branched, and cyclic alkane vapors. Read the full text of the article at 10.1002/chem.202000043.

Room-Temperature Phosphorescence from a Series of 3-Pyridylcarbazole Derivatives.

Exploration of pure metal-free organic molecules that exhibit strong room-temperature phosphorescence (RTP) is an emerging research topic. In this regard, unveiling the design principles for an efficient RTP molecule is an essential, but challenging, task. A small molecule is an ideal platform to precisely understand the fundamental role of each functional component because the parent molecule can be easily derivatized. Here, the RTP behaviors of a series of 3-pyridylcarbazole derivatives are presented. Experimental studies in combination with theoretical calculations reveal the crucial role of the n orbital on the central pyridine ring in the dramatic enhancement of the intersystem crossing between the charge-transfer-excited singlet state and the locally excited triplet states. Single-crystal X-ray crystallographic studies apparently indicate that both the pyridine ring and fluorine atom contribute to the enhancement of the RTP because of the restricted motion owing to weak C-H⋅⋅⋅N and H⋅⋅⋅F hydrogen-bonding interactions. The single crystal of the fluorine-substituted derivative shows an ultra-long phosphorescent lifetime (τP ) of 1.1 s and a phosphorescence quantum yield (ΦP ) of 1.2 %, whereas the bromine-substituted derivative exhibits τP of 0.15 s with a ΦP of 7.9 %. We believe that this work provides a fundamental and universal guideline for the generation of pure organic molecules exhibiting strong RTP.

Tuning the Optical Properties of Sulfonylaniline Derivatives: Degeneracy Breaking of Benzene Orbitals and Linkage through Nodal Planes.

The orbital degeneracy of benzene rings is resolved by an asymmetric push-pull system in 2,6-bis(methylsulfonyl)aniline (BMeSA), in which the highest occupied molecular orbital (HOMO) is located at the 4-position, while the lowest unoccupied molecular orbital (LUMO) is located at a different position and has a nodal plane through the carbon atoms at the 1- and 4-positions. Therefore, the π-extension of BMeSA at the 4-position reveals a strong overlap in the HOMO and a minimal overlap in the LUMO. Consequently, π-extended BMeSA derivatives exhibit longer absorbance and emission wavelengths in the order of the electron-donating abilities of their substituents at the 4-position, which is based on a decrease in an absolute HOMO-level-dependent HOMO-LUMO gap in accordance with the nodal arrangement. Positive fluorescent solvatochromism with polarity-dependent decrease in fluorescent intensity was also observed. The biaryls exhibited more planar geometries in the excited state than in the ground state. The charge transfer mechanism, which can be described as node-induced intramolecular charge transfer (NICT), differs from the planar intramolecular charge transfer (PICT) and twisted intramolecular charge transfer (TICT).

Cyclic arylopeptoid oligomers: synthesis and conformational propensities of peptide-mimetic aromatic macrocycles.

Macrocyclic peptide-mimetic molecules are attracting renewed attention and have found widespread application in research fields ranging from biochemical science to materials science. Herein, we describe the synthesis and structural elucidation of cyclo[n]-p-arylopeptoids (classified into cyclic aromatic ε-amino acids) bearing various side chains, namely, C[n]pAP(Rn) (where n inside brackets denotes the number of main chain units and R inside parentheses represents side chains). We investigate the influence of n and R on the macrocyclization efficiency of linear p-arylopeptoid oligomers (n = 3, 4, 5) under high-dilution conditions with or without slow addition. The structures of the cyclo[4]-p-arylopeptoids (C[4]pAP(Rn)) and their conformational dynamics are disclosed on the basis of single-crystal X-ray analyses, viable-temperature (VT) 1H NMR studies, and density functional theory (DFT) calculations. We found two representative conformations (open and closed) of cyclo[4]-p-arylopeptoids (C[4]pAP(Rn)) in the solid state and whose preference in the solution state was most likely dependent on solvent polarity. We believe that this simple but dynamic macrocyclic peptide-mimetic molecular scaffold would be attractive for developing new functional molecular tools based on rational molecular design as well as molecular library screening strategies.

GnRH agonist pre-treatment for microwave endometrial ablation in women with less than 1 centimetre myometrial thickness.

We evaluated the efficacy of gonadotropin-releasing hormone agonist (GnRHa) therapy for improving the myometrial thickness in women with thin (less than 1 cm) uterine walls, a contraindication for microwave endometrial ablation (MEA). The normal myometrium thickness was 0.5 cm, 0.7 cm and 0.9 cm. After the third GnRHa dose, the myometrial thickness increased to over 1 cm in all the three patients, and all were able to undergo MEA. The VAS score for menorrhagia improved in all the cases. The patient satisfaction levels were 10 in 2 of the 3 patients, and 5 in the other. There was no symptom recurrence, and no adjuvant therapy was administered. GnRHa therapy in women with submucous leiomyomata and a myometrial thickness of less than 1 cm could effectively thicken the myometrium, allowing for the use of MEA.

Terazulene Isomers: Polarity Change of OFETs through Molecular Orbital Distribution Contrast.

Intermolecular orbital coupling is fundamentally important to organic semiconductor performance. Recently, we reported that 2,6':2',6″-terazulene (TAz1) exhibited excellent performance as an n-type organic field-effect transistor (OFET) via molecular orbital distribution control. To validate and develop this concept, here we present three other terazulene regioisomers, which have three azulene molecules connected at the 2- or 6-position along the long axis of the azulene, thus constructing a linear expanded π-conjugation system: 2,2':6',2″-terazulene (TAz2), 2,2':6',6″-terazulene (TAz3), and 6,2':6',6″-terazulene (TAz4). TAz2 and TAz3 exhibit ambipolar characteristics; TAz4 exhibits clear n-type transistor behavior as an OFET. The lowest unoccupied molecular orbitals (LUMOs) of all terazulenes are fully delocalized over the entire molecule. In contrast, the highest occupied molecular orbitals (HOMOs) of TAz2 and TAz3 are delocalized over the 2,2'-biazulene units; the HOMOs of TAz4 are localized at one end of the azulene unit. These findings confirm that terazulene isomers which are simple hydrocarbon compounds are versatile materials with a tunable-polarity FET characteristic that depends on the direction of the azulene unit and the related contrast of the molecular orbital distribution in the terazulene backbone.

Chloride Selective Macrocyclic Bisurea Derivatives with 2,2'-Binaphthalene Moieties as Spacers.

A cyclic bisurea derivative 2a has been successfully prepared from the corresponding diamine and diisocyanate in the presence of tetrabutylammonium chloride as a template. A more soluble cyclic bisurea 2b has also been prepared by introduction of sterically bulky tert-butyl groups. X-ray crystal analyses of [2a·Cl]- and [2b·Cl]- revealed that overall structure was saddle like and the chloride anion was located in the center of the cavity. The bound chloride anion was hydrogen bonded by four N-H of urea groups and weakly hydrogen bonded by four 1-C-H of naphthyl groups, respectively. After removal of the bound chloride anions of [2b·Cl]- with silver nitrate, two different X-ray crystals of free 2b were obtained; one was intermolecular hydrogen bonded shrunken structure and the other was extended structure. Receptor 2b showed large binding ability for Cl-, however, the selectivity for Cl- against basic anions, such as AcO- and F-, has been insufficient. In aqueous MeCN, the association constant of 2b for Cl- was reduced but still large, and the selectivity for hydrophobic Cl- was greatly improved. In this solvent, 2b also selectively recognized alkaline metal chloride salts. Therefore, cyclic bisurea 2b is highly selective and effective Cl- selective receptor.

KRAS/BRAF Analysis in Ovarian Low-Grade Serous Carcinoma Having Synchronous All Pathological Precursor Regions.

Ovarian low-grade serous carcinoma is thought to begin as a serous cystadenoma or adenofibroma that progresses in a slow stepwise fashion. Among the low-grade serous carcinomas, there is a high frequency of activating mutations in the KRAS or BRAF genes; however, it remains unclear as to how these mutations contribute to tumor progression. This is the first report to track the histopathological progression of serous adenofibroma to low-grade serous carcinoma. Each stage was individually analyzed by pathological and molecular genetic methods to determine what differences occur between the distinct stages of progression.

A case with life-threatening uterine bleeding due to postmenopausal uterine arteriovenous malformation.

BACKGROUND: Uterine arteriovenous malformation is a rare but life-threatening condition that accounts for 1-2% of massive vaginal bleeding. Uterine arteriovenous malformations are less common after menopause. The condition can be diagnosed using Doppler ultrasound, magnetic resonance imaging, computed tomography, and pelvic angiography. CASE PRESENTATION: We report a postmenopausal patient with a uterine arteriovenous malformation who underwent emergency hysterectomy for sudden onset of life-threatening uterine bleeding following an initially successful but ultimately failed uterine artery embolization. Interestingly, it was not difficult to ligate and cut the dilated vessels and we were able to safely perform the hysterectomy with little bleeding in the operative field. The hysterectomy was successful, with most of the intraoperative vaginal blood loss due to the ruptured arteriovenous malformation. One year after surgery, the patient has had no vaginal bleeding. CONCLUSION: We consider hysterectomy to be a comparatively safe and effective therapeutic option for postmenopausal women who suffered from uterine arteriovenous malformations with life-threatening uterine bleeding.

Efficacy of multiple microwave endometrial ablation technique for menorrhagia resulting from adenomyosis.

AIM: Conventional microwave endometrial ablation (MEA) can be insufficient to control menorrhagia resulting from adenomyosis. We compared the standard single ablation technique with multiple MEA - repeating ablation three times in the same region - in patients with adenomyosis and menorrhagia. MATERIAL AND METHODS: We performed single MEA in 18 patients and multiple MEA in seven patients between 2007 and 2013. We compared the efficacy of single and multiple MEA using a visual analog scale (VAS) for menorrhagia, dysmenorrhea, and patient satisfaction. We also evaluated the incidence of menorrhagia recurrence, amenorrhea, and procedure complications in relation to patients' clinical factors. RESULTS: VAS scores for improved menorrhagia and patient satisfaction were significantly higher in the multiple MEA group than in the single MEA group; however, the operative time was longer in the multiple-treatment group. There were no statistical differences between groups in hemoglobin levels, VAS improvement for dysmenorrhea, menorrhagia recurrence, frequency of complications, or amenorrhea rate. CONCLUSION: Multiple MEA successfully controls menorrhagia from adenomyosis and achieves a higher satisfaction rate than single MEA.

Single Benzene Green Fluorophore: Solid-State Emissive, Water-Soluble, and Solvent- and pH-Independent Fluorescence with Large Stokes Shifts.

Benzene is the simplest aromatic hydrocarbon with a six-membered ring. It is one of the most basic structural units for the construction of π conjugated systems, which are widely used as fluorescent dyes and other luminescent materials for imaging applications and displays because of their enhanced spectroscopic signal. Presented herein is 2,5-bis(methylsulfonyl)-1,4-diaminobenzene as a novel architecture for green fluorophores, established based on an effective push-pull system supported by intramolecular hydrogen bonding. This compound demonstrates high fluorescence emission and photostability and is solid-state emissive, water-soluble, and solvent- and pH-independent with quantum yields of Φ=0.67 and Stokes shift of 140 nm (in water). This architecture is a significant departure from conventional extended π-conjugated systems based on a flat and rigid molecular design and provides a minimum requirement for green fluorophores comprising a single benzene ring.