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1.
Foot Ankle Int ; : 10711007241239335, 2024 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-38563279

RESUMO

BACKGROUND: Patients with moderate to severe hallux valgus (HV) sometimes exhibit second metatarsophalangeal (MTP) joint dislocation. Second MTP joint instability due to plantar plate (PP) injury has been suggested as one of the causes. However, there have been no reports that quantitatively evaluate this instability. This study aimed to evaluate second MTP joint instability in patients with HV without dislocation via ultrasonography and investigate its relationship with the presence of PP injury or foot form. METHODS: Between May 2018 and July 2023, symptomatic female patients with HV without any lesser toe deformity were included in this study. Second MTP joint instability was defined as the dorsal displacement ratio (DDR) of the passively subluxated proximal phalangeal articular surface on the metatarsal head articular surface. The presence of PP injury was assessed using ultrasonography. Foot "form" was determined by measuring standard foot bony angles on weight-bearing foot-ankle radiographs. The relationship between DDR or PP injury and radiographic measurements was investigated. RESULTS: Sixty-four patients (100 feet) were included. The average DDR of the second MTP joint in patients with HV without dislocation was 35.7%. There was an increase in the probability of PP injury, above a cutoff DDR value r of 35.4% (area under the curve = 0.712). The sensitivity, specificity, positive predictive value, and negative predictive value for the presence of PP injury based on this cutoff level were 63.9%, 74.4%, 79.6%, and 56.9%, respectively. Metatarsalgia was reported in 21 feet (21.0%), of which 15 feet (71.4%) showed PP injury. An increase in DDR was weakly associated with increased metatarsus adductus angle and decreased second metatarsal height. CONCLUSION: In female patients with HV without second MTP dislocation, we found ultrasonographic evidence of second MTP plantar plate injury and joint instability to be a relatively common finding with a high prevalence in those with localized metatarsalgia. LEVEL OF EVIDENCE: Level II, development of diagnostic criteria based on consecutive patients.

2.
Chem Pharm Bull (Tokyo) ; 72(4): 385-388, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38631893

RESUMO

Ephedra plants, the main components of which are ephedrine alkaloids, are used as traditional medicines in Eastern Asian countries. In this study, we isolated non-ephedrine constituents from various Ephedra plant species cultivated in Japan. HPLC analysis suggested that kynurenic acid and its derivatives accumulated in a wide range of Ephedra plant species. Furthermore, a large amount of (2R,3S)-O-benzoyl isocitrate has been isolated from E. intermedia. This study suggests that Ephedra plants have diverse non-ephedrine constituents.


Assuntos
Alcaloides , Ephedra , Efedrina , Japão , Cromatografia Líquida de Alta Pressão
3.
Molecules ; 29(6)2024 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-38542853

RESUMO

Zingiber purpureum Roscoe, known as plai in Thailand, is a perennial plant of the Zingiberaceae family and has traditionally been used in Southeast Asian countries to treat inflammation, pain, and asthma. In this study, we performed the characterization of the volatile constituents in ethyl acetate extracts of plai. Ethyl acetate extracts derived from the rhizomes of plai were subjected to gas chromatography-mass spectrometry, and the key peaks in the total ion current chromatograms were annotated or identified. In total, twenty-one compounds were identified using isolation procedures or standards, and nine compounds were annotated by comparing their Kovats retention index (RI) and electron ionization (EI) mass spectra with those in the literature. Most of the identifications were inconsistent with the tentative annotations found via library search and suggested that some peaks were incorrectly assigned in previous studies. Thus, to avoid further misannotations and contribute to the research on dereplication, the RI value, EI mass spectral data, and NMR spectroscopy data of the isolated compounds are reported.


Assuntos
Zingiberaceae , Cromatografia Gasosa-Espectrometria de Massas , Zingiberaceae/química , Acetatos , Extratos Vegetais/química , Tailândia
4.
Org Lett ; 26(11): 2180-2185, 2024 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-38466232

RESUMO

We have developed visible-light-induced trans-hydroboration of diaryl alkynes via direct photoexcitation of in-situ-generated diboron complexes, affording previously elusive (E)-1,2-diaryl-vinylboronates with high stereoselectivity. Experimental, spectroscopic, and theoretical mechanistic studies revealed that the triplet-state borate complex facilitates B-B bond cleavage and the desired C-B bond formation. This methodology does not require any catalyst and is operationally simple. The highly borylated 1,2-diaryl alkenes [1-(2-borylphenyl)vinyl)boronates] are shown to be useful as building blocks.

5.
Sci Rep ; 14(1): 3369, 2024 03 05.
Artigo em Inglês | MEDLINE | ID: mdl-38443414

RESUMO

Coral reef ecosystems supported by environmentally sensitive reef-building corals face serious threats from human activities. Our understanding of these reef threats is hampered by the lack of sufficiently sensitive coral environmental impact assessment systems. In this study, we established a platform for metabolomic analysis at the single-coral-polyp level using state-of-the-art mass spectrometry (probe electrospray ionization/tandem mass spectrometry; PESI/MS/MS) capable of fine-scale analysis. We analyzed the impact of the organic UV filter, benzophenone (BP), which has a negative impact on corals. We also analyzed ammonium and nitrate samples, which affect the environmental sensitivity of coral-zooxanthella (Symbiodiniaceae) holobionts, to provide new insights into coral biology with a focus on metabolites. The method established in this study breaks new ground by combining PESI/MS/MS with a technique for coral polyps that can control the presence or absence of zooxanthellae in corals, enabling functions of zooxanthellae to be assessed on a polyp-by-polyp basis for the first time. This system will clarify biological mechanisms of corals and will become an important model system for environmental impact assessment using marine organisms.


Assuntos
Antozoários , Dinoflagelados , Pólipos , Humanos , Animais , Ecossistema , Espectrometria de Massas em Tandem , Recifes de Corais
6.
J Nat Prod ; 2024 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-38358957

RESUMO

Clerodane diterpenes are a class of secondary metabolites that can be classified into four types according to the configuration of the H3-19/H-10-H3-17/H3-20 fragment, i.e., trans-cis (TC), trans-trans (TT), cis-cis (CC), and cis-trans (CT). Tinotufolins A-C and E (1a-3a and 5a), isolated from the leaves of Tinospora crispa, were previously elucidated as CT-type clerodanes; however, our established 13C NMR-based empirical rules and density functional theory calculations suggested that these clerodanes belong to the CC type. Therefore, tinotufolins A-F (1-6) were reisolated from the leaves of T. crispa, along with an undescribed compound 7 and known compounds 8-11, and their structures were established by extensive spectroscopic analyses. The structures of tinotufolins A-C and E were revised to CC-type 1-3 and 5, and undescribed compound 7 was established as a CC-type clerodane. The present study demonstrates that empirical rules and calculations can efficiently identify and revise erroneous structures in clerodane diterpenes.

7.
Cells ; 13(3)2024 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-38334622

RESUMO

Neuronal cell death is a key mechanism involved in the development and exacerbation of Parkinson's disease (PD). The excessive production of reactive oxygen species (ROS) is a major cause leading to neuronal death; therefore, compounds that prevent oxidative stress-dependent neuronal death may be promising as a preventive method for PD. Ergothioneine is a natural amino acid with antioxidant properties, and its protective functions in the body are attracting attention. However, there has been no investigation into the protective functions of ergothioneine using in vivo and in vitro PD models. Thus, in this study, we analyzed the efficacy of ergothioneine against 6-hydroxydopamine (6-OHDA)-dependent neuronal cell death using immortalized hypothalamic neurons (GT1-7 cells). First, we found that ergothioneine prevents 6-OHDA-dependent neuronal cell death by suppressing ROS overproduction in GT1-7 cells. The cytoprotective effect of ergothioneine was partially abolished by verapamil, an inhibitor of OCTN1, which is involved in ergothioneine uptake. Furthermore, ergothioneine-rich Rice-koji (Ergo-koji) showed cytoprotective and antioxidant effects similar to those of ergothioneine. Taken together, these results suggest that ergothioneine or foods containing ergothioneine may be an effective method for preventing the development and progression of PD.


Assuntos
Ergotioneína , Ergotioneína/farmacologia , Ergotioneína/metabolismo , Oxidopamina/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Neurotoxinas/farmacologia , Morte Celular , Antioxidantes/farmacologia , Antioxidantes/metabolismo
8.
Pathology ; 56(1): 81-91, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38110323

RESUMO

Myeloid sarcoma is a rare extramedullary haematopoietic malignancy. Interaction between CD47 and signal regulatory protein α (SIRPα) inhibits phagocytosis. CD47-positive tumours confer poor prognoses in various malignant tumours, including acute myeloid leukaemia. This study aimed to investigate the clinicopathological effects of CD47 and SIRPα expression in myeloid sarcoma. Immunohistochemistry (IHC) of CD47 and SIRPα was performed in 84 biopsy samples obtained from patients with myeloid sarcoma, some of which were CD47-positive. Patients were categorised into the following two groups based on IHC of SIRPα: those with SIRPα-positive neoplastic cells (nSIRPα) and, SIRPα expression on non-neoplastic stromal cells in tumour microenvironment (miSIRPα). In addition, patients with CD47 positivity had higher lymphocytic infiltration into the tumour microenvironment. Overall, these patients had significantly higher overall survival, however, no significant difference was observed in progression-free survival. No significant prognostic differences were observed between the nSIRPα and miSIRPα groups. This is the first study to demonstrate an association between CD47 expression and improved prognosis in myeloid sarcoma. Nonetheless, it will be necessary to conduct additional research on gene expression and genomic abnormalities to elucidate the corresponding pathogenesis of myeloid sarcoma.


Assuntos
Leucemia Mieloide Aguda , Sarcoma Mieloide , Humanos , Receptores Imunológicos/genética , Receptores Imunológicos/metabolismo , Prognóstico , Sarcoma Mieloide/diagnóstico , Antígenos de Diferenciação/genética , Antígenos de Diferenciação/metabolismo , Antígeno CD47/genética , Microambiente Tumoral
9.
Hematol Rep ; 15(4): 662-669, 2023 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-38132275

RESUMO

We report a case of a 24-year-old man who developed angioimmunoblastic T-cell lymphoma (AITL) after treatment for refractory lymphocyte-rich classic Hodgkin lymphoma (LR-CHL). This patient was treated with the BV+AVD (brentuximab vedotin, doxorubicin, vinblastine, and dacarbazine) protocol for LR-CHL but progressed before completing chemotherapy. The pathological imaging showed the typical findings of LR-CHL at the first onset and first progression. Rescue chemotherapy and high-dose chemotherapy combined with autologous hematopoietic stem cell transplantation (AHSCT) were performed for refractory LR-CHL, and complete remission was achieved. However, the recurrence was suspected 6 months after AHSCT. The pathological findings of the lymph node biopsy at this time were different from those of the previous two lymph node biopsies, demonstrating findings of AITL. The finding of the immunohistochemical staining and polymerase chain reaction results supported the diagnosis. Although it has been reported that the risk for the development of non-Hodgkin lymphoma after treatment for Hodgkin lymphoma is increased, most are B-cell lymphomas, and few cases of AITL have been reported. AITL is a type of peripheral T-cell lymphoma that generally occurs in middle-aged and elderly people and that rarely occurs in young people. Here, we were able to make an accurate diagnosis by performing re-examination even when recurrence of LR-CHL was suspected. As there are no detailed case reports of AITL developing into secondary non-Hodgkin lymphoma, here we report on an identified case.

10.
Exp Ther Med ; 26(5): 510, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37840568

RESUMO

The abscopal effect is a rare phenomenon that is defined as regression of tumor lesions distant from irradiation targets. At our department, two cases with an abscopal effect with fever of unknown cause (FUC) and an inflammatory response during radiotherapy were encountered. Radiotherapy is a local treatment; therefore, it rarely causes systemic side effects during radiotherapy, and if a patient develops a fever during radiotherapy, it is frequently considered tumor fever. We experienced 2 cases of FUC during irradiation followed by abscopal effect. The obvious relationship between the abscopal effect and the fever remains to be clarified. However, FUC during radiotherapy may be a hint to the abscopal effect, considering that immune response and cytokines are closely related to the abscopal effect.

11.
JBJS Case Connect ; 13(3)2023 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-37651574

RESUMO

CASE: Distal phalangeal fractures are often treated conservatively. However, some patients experience residual pain. We report 2 cases of patients who underwent low-intensity pulsed ultrasound (LIPUS) therapy for pseudarthrosis after fracture of the distal phalanx of the fifth toe with symphalangism. Both patients (female, 63 and 33-year-old, respectively) underwent conservative treatment with buddy-taping fixation; however, bone union failed, and LIPUS therapy was initiated. In both cases, bone union was achieved and pain resolved after 3 months. CONCLUSION: Bone union occasionally fails after conservative treatment of distal phalangeal fractures. LIPUS is a useful treatment of symptomatic pseudarthrosis after such fractures.


Assuntos
Traumatismos do Tornozelo , Traumatismos dos Dedos , Fraturas Ósseas , Fraturas Múltiplas , Traumatismos do Joelho , Pseudoartrose , Humanos , Feminino , Pseudoartrose/diagnóstico por imagem , Pseudoartrose/terapia , Fraturas Ósseas/complicações , Fraturas Ósseas/diagnóstico por imagem , Fraturas Ósseas/terapia , Dedos do Pé , Dor , Ondas Ultrassônicas
12.
J Nat Med ; 77(4): 880-890, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37587329

RESUMO

The roots of Polygonum multiflorum Thunberg (Polygonaceae) are used as a crude drug Kashu that is considered to improve blood deficiency based on a Kampo concept. Kashu has been included in Kampo formulas, such as Tokiinshi, which is used to treat eczema and dermatitis with itchiness by inhibiting inflammation and facilitating blood circulation in the skin. However, the effects of P. multiflorum roots on erythropoiesis are unclear. Previously, we isolated six phenolic constituents from an ethyl acetate (EtOAc)-soluble fraction of P. multiflorum root extract and identified them as (E)-2,3,5,4'-tetrahydroxystilbene-2-O-ß-D-glucopyranoside [(E)-THSG], emodin, emodin-8-O-ß-D-glucopyranoside, physcion, physcion-8-O-ß-D-glucopyranoside, and catechin. To examine whether P. multiflorum roots facilitate erythropoiesis, the EtOAc-soluble fraction was orally administered to healthy ICR mice. When compared with mice fed a standard diet alone (Controls), the mice fed a diet including the EtOAc-soluble fraction exhibited significantly higher serum erythropoietin (Epo) levels. The renal Epo mRNA levels in EtOAc-soluble fraction-administered mice were significantly higher than those in the control mice. Then, we administered roxadustat, which is a drug to treat the patient suffering with renal anemia by specifically inhibiting hypoxia-inducible factor prolyl hydroxylases. Roxadustat slightly increased renal Epo mRNA levels in healthy mice. Administration of (E)-THSG, a major constituent, significantly increased serum Epo levels. It is likely that (E)-THSG may facilitate the process to convert inactive renal Epo-producing cells to active Epo-producing cells. Collectively, it is implied that (E)-THSG in the EtOAc-soluble fraction of P. multiflorum roots may primarily improve blood deficiency of Kampo concept by promoting erythropoiesis.


Assuntos
Emodina , Eritropoetina , Fallopia multiflora , Animais , Camundongos , Camundongos Endogâmicos ICR
13.
Molecules ; 28(13)2023 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-37446738

RESUMO

The roots of Peucedanum praeruptorum Dunn and Angelica decursiva Franchet et Savatier are designated Zenko, which is a crude drug defined by the Japanese Pharmacopoeia. This crude drug is used as an antitussive and an expectorant and is included in the Kampo formula Jinsoin, which improves cough, fever, and headache. Although the anti-inflammatory effects of this crude drug have been determined, the constituents responsible for this effect remain unknown. To investigate biologically active compounds, rat hepatocytes were used, which produce proinflammatory mediator nitric oxide (NO) in response to proinflammatory cytokine interleukin 1ß (IL-1ß). A methanol extract of P. praeruptorum roots, which suppressed IL-1ß-induced NO production, was fractionated into three crude fractions (ethyl acetate (EtOAc)-soluble, n-butanol-soluble, and water-soluble fractions) based on hydrophobicity. The EtOAc-soluble fraction markedly inhibited NO production. After this fraction was purified, three biologically active compounds were identified as praeruptorins A, B, and E, the contents of which were high. A comparison of their activities indicated that praeruptorin B exhibited the highest potency to inhibit NO production by decreasing inducible NO synthase expression and suppressed the expression of mRNAs encoding proinflammatory cytokines. Collectively, the three praeruptorins may primarily contribute to the anti-inflammatory effects of P. praeruptorum roots.


Assuntos
Óxido Nítrico , Extratos Vegetais , Ratos , Animais , Extratos Vegetais/farmacologia , Extratos Vegetais/metabolismo , Óxido Nítrico/metabolismo , Interleucina-1beta/metabolismo , Anti-Inflamatórios/farmacologia , Anti-Inflamatórios/metabolismo , Hepatócitos , Citocinas/metabolismo , Óxido Nítrico Sintase Tipo II/metabolismo
15.
Nutrients ; 15(9)2023 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-37432185

RESUMO

Trace elements such as iron (Fe), zinc (Zn), copper (Cu), and manganese (Mn) are absorbed from food via the gastrointestinal tract, transported into the brain, and play central roles in normal brain functions. An excess of these trace elements often produces reactive oxygen species and damages the brain. Moreover, increasing evidence suggests that the dyshomeostasis of these metals is involved in the pathogenesis of neurodegenerative diseases, including Alzheimer's disease, prion diseases, and Lewy body diseases. The disease-related amyloidogenic proteins can regulate metal homeostasis at the synapses, and thus loss of the protective functions of these amyloidogenic proteins causes neurodegeneration. Meanwhile, metal-induced conformational changes of the amyloidogenic proteins contribute to enhancing their neurotoxicity. Moreover, excess Zn and Cu play central roles in the pathogenesis of vascular-type senile dementia. Here, we present an overview of the intake, absorption, and transport of four essential elements (Fe, Zn, Cu, Mn) and one non-essential element (aluminum: Al) in food and their connections with the pathogenesis of neurodegenerative diseases based on metal-protein, and metal-metal cross-talk.


Assuntos
Doença de Alzheimer , Demência Vascular , Doenças Neurodegenerativas , Oligoelementos , Humanos , Doenças Neurodegenerativas/etiologia , Dieta , Doença de Alzheimer/etiologia , Zinco , Manganês , Proteínas Amiloidogênicas
16.
Int J Mol Sci ; 24(12)2023 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-37373184

RESUMO

As overproduction of reactive oxygen species (ROS) causes various diseases, antioxidants that scavenge ROS, or inhibitors that suppress excessive ROS generation, can be used as therapeutic agents. From a library of approved drugs, we screened compounds that reduced superoxide anions produced by pyocyanin-stimulated leukemia cells and identified benzbromarone. Further investigation of several of its analogues showed that benziodarone possessed the highest activity in reducing superoxide anions without causing cytotoxicity. In contrast, in a cell-free assay, benziodarone induced only a minimal decrease in superoxide anion levels generated by xanthine oxidase. These results suggest that benziodarone is an inhibitor of NADPH oxidases in the plasma membrane but is not a superoxide anion scavenger. We investigated the preventive effect of benziodarone on lipopolysaccharide (LPS)-induced murine lung injury as a model of acute respiratory distress syndrome (ARDS). Intratracheal administration of benziodarone attenuated tissue damage and inflammation via its ROS-reducing activity. These results indicate the potential application of benziodarone as a therapeutic agent against diseases caused by ROS overproduction.


Assuntos
Lesão Pulmonar , Camundongos , Animais , Humanos , Espécies Reativas de Oxigênio/metabolismo , Superóxidos , Lipopolissacarídeos/toxicidade , NADPH Oxidases/metabolismo
17.
Int J Mol Sci ; 24(11)2023 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-37298708

RESUMO

Parkinson's disease (PD) is a neurodegenerative disorder caused by oxidative stress-dependent loss of dopaminergic neurons in the substantia nigra and elevated microglial inflammatory responses. Recent studies show that cell loss also occurs in the hypothalamus in PD. However, effective treatments for the disorder are lacking. Thioredoxin is the major protein disulfide reductase in vivo. We previously synthesized an albumin-thioredoxin fusion protein (Alb-Trx), which has a longer plasma half-life than thioredoxin, and reported its effectiveness in the treatment of respiratory and renal diseases. Moreover, we reported that the fusion protein inhibits trace metal-dependent cell death in cerebrovascular dementia. Here, we investigated the effectiveness of Alb-Trx against 6-hydroxydopamine (6-OHDA)-induced neurotoxicity in vitro. Alb-Trx significantly inhibited 6-OHDA-induced neuronal cell death and the integrated stress response. Alb-Trx also markedly inhibited 6-OHDA-induced reactive oxygen species (ROS) production, at a concentration similar to that inhibiting cell death. Exposure to 6-OHDA perturbed the mitogen-activated protein kinase pathway, with increased phosphorylated Jun N-terminal kinase and decreased phosphorylated extracellular signal-regulated kinase levels. Alb-Trx pretreatment ameliorated these changes. Furthermore, Alb-Trx suppressed 6-OHDA-induced neuroinflammatory responses by inhibiting NF-κB activation. These findings suggest that Alb-Trx reduces neuronal cell death and neuroinflammatory responses by ameliorating ROS-mediated disruptions in intracellular signaling pathways. Thus, Alb-Trx may have potential as a novel therapeutic agent for PD.


Assuntos
Estresse Oxidativo , Doença de Parkinson , Albuminas/metabolismo , Fatores Imunológicos/farmacologia , Oxidopamina/toxicidade , Doença de Parkinson/tratamento farmacológico , Doença de Parkinson/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Tiorredoxinas/metabolismo , Animais , Camundongos , Neurônios/efeitos dos fármacos , Neurônios/metabolismo
18.
Virchows Arch ; 483(2): 255-260, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37270432

RESUMO

Classic Hodgkin lymphoma (CHL) harbors a small number of Hodgkin-Reed-Sternberg (HRS) cells scattered among numerous lymphocytes. HRS cells are surrounded by distinct CD4+ T cells in a rosette-like manner. These CD4+ T cell rosettes play an important role in the tumor microenvironment (TME) of CHL. To elucidate the interaction between HRS cells and CD4+ T cell rosettes, we completed digital spatial profiling to compare the gene expression profiles of CD4+ T cell rosettes and other CD4+ T cells separated from the HRS cells. Immune checkpoint molecules including OX40, programed cell death-1 (PD-1), and cytotoxic T lymphocyte associated protein 4 (CTLA-4) expression was higher in CD4+ T cell rosettes compared to other CD4+ T cells. Immunohistochemistry confirmed variable PD-1, CTLA-4, and OX40 expression in the CD4+ T cell rosettes. This study introduced a new pathological approach to study the CHL TME, and provided deeper insight into CD4+ T cells in CHL.


Assuntos
Doença de Hodgkin , Humanos , Doença de Hodgkin/patologia , Linfócitos T/metabolismo , Antígeno CTLA-4 , Receptor de Morte Celular Programada 1/metabolismo , Células de Reed-Sternberg/metabolismo , Linfócitos T CD4-Positivos , Microambiente Tumoral
19.
Org Lett ; 25(23): 4225-4230, 2023 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-37219051

RESUMO

We have achieved the enantioselective synthesis of axially chiral figure-eight spiro[9.9]cycloparaphenylene (CPP) tetracarboxylates with up to 75:25 er via the cationic Rh(I)/(R)-H8-BINAP complex-catalyzed chemo-, regio-, and enantioselective intermolecular double [2 + 2 + 2] cycloaddition of an achiral symmetric tetrayne with dialkyl acetylenedicarboxylates followed by reductive aromatization. The spiro[9.9]CPP tetracarboxylates are highly distorted at the phthalate moieties with large dihedral and boat angles and exhibit weak aggregation-induced emission enhancement behavior.


Assuntos
Ródio , Reação de Cicloadição , Estereoisomerismo
20.
Angew Chem Int Ed Engl ; 62(24): e202304041, 2023 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-37041121

RESUMO

Covalent organic cages have potential applications in molecular inclusion/recognition and porous organic crystals. Bridging arene units with sp3 atoms enables facile construction of rigid isolated internal vacancies, and various prismatic arene cages have been synthesized by kinetically controlled covalent bond formation. However, the synthesis of a tetrahedral one, which requires twice as much bond formation as prismatic ones, has been limited to a thermodynamically controlled dynamic SN Ar reaction, and this reversible covalent bond formation made the resulting cage product chemically unstable. Here we report the Rh-catalyzed high-yielding and highly 1,3,5-selective room temperature [2+2+2] cycloaddition of push-pull alkynes and its application to the synthesis of chemically stable aryl ether cages of various shapes and sizes, including prismatic and tetrahedral forms. These aryl ether cages are highly crystalline and intertwine with each other to form regular packing structures. Some aryl ether cages encapsulated isolated water molecules in their hydrophobic cavity by hydrogen bonding with the multiple ester moieties.

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