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1.
Nature ; 2024 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-38898283

RESUMO

Glassy polymers are generally stiff and strong yet have limited extensibility1. By swelling with solvent, glassy polymers can become gels that are soft and weak yet have enhanced extensibility1-3. The marked changes in properties arise from the solvent increasing free volume between chains while weakening polymer-polymer interactions. Here we show that solvating polar polymers with ionic liquids (that is, ionogels4,5) at appropriate concentrations can produce a unique class of materials called glassy gels with desirable properties of both glasses and gels. The ionic liquid increases free volume and therefore extensibility despite the absence of conventional solvent (for example, water). Yet, the ionic liquid forms strong and abundant non-covalent crosslinks between polymer chains to render a stiff, tough, glassy, and homogeneous network (that is, no phase separation)6, at room temperature. Despite being more than 54 wt% liquid, the glassy gels exhibit enormous fracture strength (42 MPa), toughness (110 MJ m-3), yield strength (73 MPa) and Young's modulus (1 GPa). These values are similar to those of thermoplastics such as polyethylene, yet unlike thermoplastics, the glassy gels can be deformed up to 670% strain with full and rapid recovery on heating. These transparent materials form by a one-step polymerization and have impressive adhesive, self-healing and shape-memory properties.

2.
Support Care Cancer ; 32(3): 207, 2024 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-38436749

RESUMO

PURPOSE: Children with leukemia may experience a range of chemotherapy-related symptoms. Identifying subgroups and their distinct characteristics of symptoms may improve symptom management. We aimed to identify subgroups and their distinct characteristics of chemotherapy-related symptoms in children with leukemia. METHODS: A cross-sectional survey was conducted among 500 children with leukemia, who completed questionnaires that assessed their demographic and clinical characteristics, as well as the Memorial Symptom Assessment Scale. Latent profile analysis was conducted to identify subgroups of symptoms. Additionally, multiple regression analysis and network analysis were utilized to reveal the characteristics of each subgroup. RESULTS: Four subgroups were identified: "Profile 1: low symptom burden subgroup" (26.2%), "Profile 2: moderate symptom burden subgroup in transitional period" (14.8%), "Profile 3: moderate psychological symptom burden subgroup" (35.6%), and "Profile 4: high symptom burden subgroup" (23.4%). Multiple logistic regression analysis indicated that lower primary caregiver's education level, lower family monthly income, self-paid medical expenses, induction remission period, and consolidation enhancement period were associated with more severe symptoms of subgroups. Network analysis further revealed that nausea was the core symptom in Profiles 1 and 2, while the core symptom in Profile 3 was "I don't look like myself." Additionally, worrying was the core symptom in Profile 4. CONCLUSION: There exists heterogeneity in chemotherapy-related symptoms. Four subgroups and their corresponding characteristics of children with varying symptom severity were identified. Identifying these subgroups will facilitate personalized care, maximize intervention effectiveness, and alleviate symptom burden.


Assuntos
Leucemia , Criança , Humanos , Estudos Transversais , Leucemia/tratamento farmacológico , Escolaridade , Renda , Náusea
3.
Nat Mater ; 21(3): 359-365, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-35190655

RESUMO

Ionogels are compelling materials for technological devices due to their excellent ionic conductivity, thermal and electrochemical stability, and non-volatility. However, most existing ionogels suffer from low strength and toughness. Here, we report a simple one-step method to achieve ultra-tough and stretchable ionogels by randomly copolymerizing two common monomers with distinct solubility of the corresponding polymers in an ionic liquid. Copolymerization of acrylamide and acrylic acid in 1-ethyl-3-methylimidazolium ethyl sulfate results in a macroscopically homogeneous covalent network with in situ phase separation: a polymer-rich phase with hydrogen bonds that dissipate energy and toughen the ionogel; and an elastic solvent-rich phase that enables for large strain. These ionogels have high fracture strength (12.6 MPa), fracture energy (~24 kJ m-2) and Young's modulus (46.5 MPa), while being highly stretchable (~600% strain) and having self-healing and shape-memory properties. This concept can be applied to other monomers and ionic liquids, offering a promising way to tune ionogel microstructure and properties in situ during one-step polymerization.


Assuntos
Líquidos Iônicos , Condutividade Elétrica , Géis/química , Ligação de Hidrogênio , Líquidos Iônicos/química , Polímeros
4.
Acc Chem Res ; 55(19): 2796-2810, 2022 10 04.
Artigo em Inglês | MEDLINE | ID: mdl-35994690

RESUMO

Recent decades have witnessed a resurgence of the study of copper-catalyzed organic reactions. As the surrogate of noble metal catalysts, copper salts have been shown to exhibit remarkable versatility in activating various C-H bonds enabling the construction of diverse carbon-carbon and carbon-heteroatom bonds. Advantageously, copper salts are also naturally abundant, inexpensive, and less toxic in comparison to precious metals. Despite significant developments in synthesis, the mechanism of copper catalysis remains elusive. Hypothetical pathways such as the two-electron Cu(III)/Cu(I) and Cu(II)/Cu(0) catalytic cycles and the one-electron Cu(II)/Cu(I) catalytic cycle have been invoked to diagram C-H bond transformations because of the formidable challenges to isolate and characterize transient high valent organocopper intermediates. In fact, organocopper chemistry has been dominated for a long time by the acknowledged nucleophilic organocopper(I) compounds. Since the beginning of the new millennium, we have been systematically studying the supramolecular chemistry of heteracalix[n]aromatics. Owing to the ease of their synthesis and selective functionalizations, self-tunable conformation and cavity structures resulting from the interplay of heteroatoms with aromatic subunits, and outstanding properties in molecular recognition and self-assembly, heteracalix[n]aromatics have become a class of privileged synthetic macrocyclic hosts. Our journey to the chemistry of high valent organocopper compounds started with a serendipitous discovery of the facile formation of a stable organocopper compound, which contains astonishingly a Ph-Cu(III) σ-bond under very mild aerobic conditions. When we examined routinely the effect of the macrocyclic structures on noncovalent complexation properties, titration of tetraazacalix[1]arene[3]pyridine with Cu(ClO4)2·6H2O resulted in the precipitation of dark-purple crystals of phenylcopper(III) diperchlorate. Our curiosity about the transformation of an arene C-H bond into an Ar-Cu(III) bond prompted us to conduct an in-depth investigation of the reaction of macrocyclic arenes with copper(II) salts, leading to the isolation of arylcopper(II) compounds which are unprecedented and the missing link in organocopper chemistry. With structurally well-defined organometallics in hand, we have explored extensively the reactivities of both arylcopper(II) and arylcopper(III) compounds, demonstrating their versatility and uniqueness in chemical synthesis. Novel and fascinating arene C-H transformations under copper catalysis have been developed. Using acquired high valent arylcopper compounds as molecular probes, and employing the functionalizations of tetraazacalix[1]arene[3]pyridines as model reactions, we have revealed the diverse mechanisms of copper-promoted arene C-H bond reactions. Elusive reaction pathways of some copper-catalyzed C-X bond activations have also been unraveled. In the meantime, we have also witnessed pleasingly the rapid development of field with the advent of new high valent organocopper compounds. Without any doubt, studies of the synthesis, reactivity, and catalysis of high valent organocopper compounds have been reshaping the field of organocopper chemistry. This Account summarizes our endeavors to explore the chemistry of structurally well-defined arylcopper(II) and arylcopper(III) compounds and the mechanisms of copper-catalyzed arene C-H and C-X bond transformations. We hope this Account will inspire chemists to study thoroughly the fundamentals and the cutting-edge catalysis of high valent organocopper compounds advancing and redefining the discipline of organocopper chemistry.


Assuntos
Cobre , Compostos de Cobre Orgânico , Carbono , Catálise , Cobre/química , Sondas Moleculares , Piridinas/química , Sais
5.
J Fluoresc ; 33(4): 1565-1576, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-36787040

RESUMO

A novel D-π-A type fluorescent probe L(NO3) for Cu (II) sensing was designed and fully characterized. The probe consists of a styryl-pyridine cation fluorescent group and a di-(2-picolyl)amine (DPA) receptor unit, which are linked by a phenyl group to form an electron donor-π-acceptor (D-π-A) conjugate system, especially the introduction of a nitrate counter anion for significantly enhanced water solubility of the probe. Fluorescence titration studies of the probe L(NO3) showed a higher selectivity for Cu2+ than other metal ions, and the emission spectrum was strongly quenched upon binding. The competitive binding assay and the low detection limit (0.932 µM) showed that the probe L(NO3) had strong anti-interference ability and excellent Cu2+ detection performance. The binding ratio of probe L(NO3) and Cu2+ was determined from Job's plot to be 1:1, which is consistent with the results obtained from X-ray crystal structures. Meanwhile, the probe showed instantaneous chemical reversibility when titrated with EDTA solution, indicating potential recycling properties of the probe. In addition, the design of inexpensive fluorescent test strips can perform the on-site and real-time detection Cu2+ with a color recognition application.

6.
Crit Care ; 27(1): 490, 2023 12 13.
Artigo em Inglês | MEDLINE | ID: mdl-38093296

RESUMO

BACKGROUND: Sepsis is defined as a life-threatening syndrome caused by an unbalanced host response to infection. The role of interleukin (IL)-36 cytokines binding to the IL-36 receptor (IL-36R) in host response during sepsis remains unknown. METHODS: Serum IL-36 level was measured in 47 septic patients sampled on the day of intensive care unit (ICU) and emergency department admission, 21 non-septic ICU patient controls, and 21 healthy volunteers. In addition, the effects of IL-36R deletion on host inflammatory response in cecal ligation and puncture (CLP)-induced polymicrobial sepsis was determined. RESULTS: On the day of ICU and emergency department admission, the patients with sepsis showed a significant increase in serum IL-36 levels compared with ICU patient controls and healthy volunteers, and the serum IL-36 levels were related to the severity of sepsis. Non-survivors of septic patients displayed significantly lower serum IL-36 levels compared with survivors. A high serum IL-36 level in ICU and emergency department admission was associated with 28-day mortality, and IL-36 was found to be an independent predictor of 28-day mortality in septic patients by logistic regression analysis. Furthermore, IL-36R deletion increased lethality in CLP-induced polymicrobial sepsis. Septic mice with IL-36R deletion had higher bacterial load and demonstrated more severe multiple organ injury (including lung, liver, and kidney) as indicated by clinical chemistry and histopathology. Mechanistically, IL-36R ligands released upon lung damage activated IL-36R+lung fibroblasts thereby inducing expression of the antimicrobial protein lipocalin 2. Moreover, they induced the apoptosis of lung epithelial cells. CONCLUSIONS: Septic patients had elevated serum IL-36 levels, which may correlate with disease severity and mortality. In experimental sepsis, we demonstrated a previously unrecognized role of IL-36R deletion in increasing lethality.


Assuntos
Lesão Pulmonar , Sepse , Animais , Humanos , Camundongos , Modelos Animais de Doenças , Células Epiteliais , Fibroblastos , Interleucinas
7.
Support Care Cancer ; 31(10): 578, 2023 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-37715817

RESUMO

PURPOSE: Children with acute leukemia have suffered from a considerable symptom burden during chemotherapy. However, few studies have focused on exploring the mechanisms among symptoms in children with acute leukemia. Our study aims to explore core symptoms and describe the interrelationships among symptoms in children with acute leukemia during chemotherapy. METHODS: From January 2021 to March 2023, 469 children with acute leukemia were recruited from 20 Chinese cities. The Memorial Symptom Assessment Scale 10-18 (MSAS 10-18) was used to evaluate the prevalence and severity of symptoms during chemotherapy. A network analysis was performed by the R software based on 31 symptoms. Centrality indices and density were used to explore core symptoms and describe interrelationships among symptoms in the network during chemotherapy. RESULTS: Worrying and feeling irritable were the central symptoms across the three centrality indices, including strength, closeness, and betweenness. Lack of energy was the most prevalent symptom; however, it was less central than other symptoms. The density of the "induction and remission" network significantly differed from other cycles' counterparts (p < 0.001). Global strength was greater in the " ≥ 8 years group " network than the " < 8 years group " network (p = 0.023). CONCLUSION: Network analysis provides a novel approach to identifying the core symptoms and understanding the interrelationships among symptoms. Our study indicates the need to assess emotional symptoms in children with acute leukemia during chemotherapy, especially during the induction and remission phases, as well as in older children. Future research is imperative to construct trajectories of dynamic symptom networks and centrality indices in longitudinal data to investigate the causal relationships among symptoms.


Assuntos
Antineoplásicos , Leucemia , Criança , Humanos , Povo Asiático , Emoções , Leucemia Mieloide Aguda/tratamento farmacológico , Leucemia Mieloide Aguda/epidemiologia , Software , Antineoplásicos/uso terapêutico , Leucemia/diagnóstico , Leucemia/tratamento farmacológico , Leucemia/psicologia , Doença Aguda , China
8.
Scand Cardiovasc J ; 57(1): 2286885, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38010775

RESUMO

Objectives. Studies have shown that fasting blood glucose (FBG) is closely associated with poor prognosis in patients with coronary heart disease (CHD) after percutaneous coronary intervention (PCI), but its association with in-stent restenosis (ISR) is still unclear. Therefore, this study was to explore the association between FBG with ISR in patients with CHD after PCI. Design. In this cohort study, we included 531 patients with CHD who underwent PCI. Logistic regression, receiver operating characteristic (ROC), subgroup analysis and restricted cubic spline (RCS) were used to assess the association between FBG with ISR. Results. A total of 124 (23.4%) patients had ISR. Patients with higher levels of FBG had higher incidence of ISR compared to those with lower levels of FBG (p = 0.002). In multivariable logistic regression analyses, higher levels of FBG remained strongly associated with higher risk of ISR (as a categorical variable, OR: 1.89, 95% CI: 1.21-2.94, p = 0.005; as a continuous variable, OR: 1.12, 95% CI: 1.03-1.23, p = 0.011). ROC analysis also showed that FBG might be associated with the occurrence of ISR (AUC = 0.577, 95% CI: 0.52-0.64, p = 0.013). Subgroup analyses showed the association of FBG with ISR was also stable in several subgroups (< 60 years or ≥ 60 years, male, with or without smoking, without diabetes and without hypertension). And RCS analysis showed that FBG was linearly and positively associated with the risk of ISR. Conclusions. Higher levels of FBG were closely associated with higher risk of ISR in patients with CHD after PCI.


Assuntos
Reestenose Coronária , Intervenção Coronária Percutânea , Humanos , Masculino , Intervenção Coronária Percutânea/efeitos adversos , Estudos de Coortes , Glicemia , Reestenose Coronária/etiologia , Constrição Patológica , Jejum , Angiografia Coronária/efeitos adversos , Fatores de Risco , Estudos Retrospectivos , Stents/efeitos adversos
9.
Surg Innov ; 30(3): 303-313, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-36787724

RESUMO

Objective. To evaluate the value of individualized planning of left atrial appendage occlusion (LAAO) using cardiac computed tomography angiography (CCTA) reconstruction techniques. Methods. A total of 96 patients treated for LAAO with the Watchman occluder were included in this study. All patients were randomized by random number table in a 2:1 ratio into the CCTA (+) and CCTA (-) groups according to whether CCTA was performed preoperatively. 3D cardiac reconstruction was performed preoperatively in the CCTA (+) group to plan the location of the atrial septal puncture site, left atrial appendage(LAA) landing zone, predict the size of the occluder and simulate occluder release. In the CCTA(-) group, only transesophageal echocardiography (TEE) and fluoroscopy were used to guide LAAO. Results. The number of occluders used in a single procedure (1.06 ± .24 vs 1.22 ± .42), the number of intraoperative angiography positions (1.23 ± .58 vs 2.28 ± .85) and the procedure time (45.88 ± 5.08 vs 62.44 ± 5.60) in the CCTA(+) group were lower than in the CCTA(-) group (P < .05), and the first-attempt blocking success rate was higher than that of the CCTA(-) group (85.9% vs 65.6%, P = .021). Furthermore, the Bland-Altman plots showed good agreement between the longest diameter of the CCTA-predicted landing zone and the longest diameter of the actual landing zone (95% LoA -7.49, 10.24). A strong positive correlation was observed between the predicted compression ratio and the actual compression ratio (r = .890, P < .001). In addition, a strong positive correlation was found between the CCTA-predicted longest diameter of the landing zone and the actual occluder size (r = .863, P < .001). Conclusion. Accurate planning for LAAO using preoperative CCTA can reduce intraoperative angiography positions and occluder changes, shorten the procedure time, increase the success rate of first-attempt blocking and reduce the difficulty of the procedure.


Assuntos
Apêndice Atrial , Fibrilação Atrial , Humanos , Angiografia por Tomografia Computadorizada/métodos , Apêndice Atrial/diagnóstico por imagem , Apêndice Atrial/cirurgia , Fibrilação Atrial/diagnóstico por imagem , Fibrilação Atrial/cirurgia , Tomografia Computadorizada por Raios X , Angiografia , Resultado do Tratamento
10.
Angew Chem Int Ed Engl ; 62(24): e202302646, 2023 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-37088714

RESUMO

Hydrocarbon belts have drawn great attention because of their unique structures and tantalizing properties. Although a few belts and heteroatom-doped analogs have been synthesized, belt molecules containing non-hexagonal rings remain rare. Herein we report the construction and application of unprecedented zigzag-type hydrocarbon belts which contain functionalized eight-membered rings. The synthesis features fourfold intramolecular acylation reactions of resorcin[4]arene-derived intermediates, which affords C4 -symmetric tetrabenzobelt[4]arene[4]cyclooctatrienones. Stereoselective ketone reduction with LiAlH4 and nucleophilic addition with alkynyllithiums provide the corresponding tetrahydroxylated belts. The tetraol and its methyl ether are powerful and selective hosts to form 2 : 1 and 1 : 1 complexes with cesium ion, respectively, with binding constants up to (1.71±0.33)×1011  M-2 and (1.50±0.16)×106  M-1 . In addition, enantiopure C4 -symmetric belts can emit CPL with |glum | being around 0.01.

11.
Angew Chem Int Ed Engl ; 62(15): e202301782, 2023 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-36808689

RESUMO

Herein we report a two-directional cyclization strategy for the synthesis of highly strained depth-expanded oxygen-doped chiral molecular belts of the zigzag-type. From the easily accessible resorcin[4]arenes, an unprecedented cyclization cascade generating fused 2,3-dihydro-1H-phenalenes has been developed to access expanded molecular belts. Stitching up the fjords through intramolecular nucleophilic aromatic substitution and ring-closing olefin metathesis reactions furnished a highly strained O-doped C2 -symmetric belt. The enantiomers of the acquired compounds exhibited excellent chiroptical properties. The calculated parallelly aligned electric (µ) and magnetic (m) transition dipole moments are translated to the high dissymmetry factor (|glum | up to 0.022). This study provides not only an appealing and useful strategy for the synthesis of strained molecular belts but also a new paradigm for the fabrication of belt-derived chiroptical materials with high CPL activities.

12.
Acc Chem Res ; 53(7): 1364-1380, 2020 07 21.
Artigo em Inglês | MEDLINE | ID: mdl-32559061

RESUMO

Noncovalent bond interactions provide primary driving forces for supramolecular processes ranging from molecular recognition to self-assembly of sophisticated abiotic and biological machineries. While hydrogen bonding and π-π interactions are arguably textbook concepts playing indispensable parts in various scientific disciplines, noncovalent anion-π interactions have been emerging as attractive forces between π systems and negatively charged species for just about two decades. At the beginning of this century, three research groups reported independently their computational studies on the interactions between anions and aromatic compounds, proposing attractive anion-π interactions. Since π systems such as aromatic rings are traditionally noted as electron rich entities, anions and π systems would be repulsive to each other if there are any interactions. In stark contrast to the acknowledged cation-π interactions, the seemingly counterintuitive noncovalent anion-π bindings invoked great interest in the following years. Although a plethora of calculations had been published, the lack of experimental evidence cast doubt on the existence of anion-π interactions between anions and charge-neutral aromatic systems.During the same time when anion-π interactions were coined, we were studying the chemistry of novel macrocyclic compounds, namely, heteracalixaromatics, and their applications in supramolecular chemistry. It has been shown that heteracalixaromatics are powerful and versatile macrocyclic hosts to bind various guest species forming interesting assembled structures and organometallic complexes. Being a member of heteracalixaromatics, tetraoxacalix[2]arene[2]triaizne adopts a 1,3-alternate conformational structure yielding a V-shaped cavity or cleft formed by two electron-deficient triazine rings. Advantageously, the macrocycle is able to self-tune the cavity sizes by altering the degrees of conjugation between the bridging oxygen atoms with their bonded aromatic rings in response to the guest species in present, rendering it an ideal tool to explore anion-π interactions. We initiated our study on anion-π interactions using tetraoxacalix[2]arene[2]triazine as a molecular tool with the primary aim to clarify experimentally the uncertainty of whether exclusive anion-π interactions exist between anions and charge-neutral aromatic rings. We provided for the first time concrete evidence substantiating the formation of typical anion-π interaction between the anions and 1,3,5-triazine ring and demonstrated subsequently the generality and binding motifs of anion-π interactions. We have then extended our study to anion-π interaction-directed or -driven anion recognition and selective sensing, transmembrane anion transport, molecular self-assembly, and stimuli-responsive aggregation systems. A number of new generation macrocycles and cages constructed from electron-deficient tetrazine and benzenetriimide segments have also been developed in the meantime, advancing the study of anion-π interactions. This Account summarizes our endeavors to explore nascent anion-π interactions and their applications in supramolecular chemistry. We hope this Account will inspire scientists from various disciplines to explore all aspects of the nascent yet fruitful research area of anion-π interactions.

13.
J Am Chem Soc ; 142(3): 1196-1199, 2020 01 22.
Artigo em Inglês | MEDLINE | ID: mdl-31903753

RESUMO

We report in this communication the synthesis, structure, and application of a novel type of hydrocarbon belts. Starting from inexpensive and easily available resorcin[n]arenes, a closing-all-fjords strategy featuring exhaustive triflation of phenolic hydroxyl groups followed by consecutively the transition-metal-catalyzed vinylation and intramolecular olefin metathesis allowed facile construction of belt[n]arene[n]tropilidenes (n = 4, 6), which adopt double-stranded macrocyclic belt structures with unique truncated cone cavities. Selective hydrogenation reactions of olefin and benzene subunits led to diverse hydrocarbon belts with varied structures. Moreover, the resulting molecular belts acted as synthetic host materials to include selectively small molecules such as nitromethane and p-xylene.

14.
J Am Chem Soc ; 142(10): 4576-4580, 2020 03 11.
Artigo em Inglês | MEDLINE | ID: mdl-32084314

RESUMO

Hydrocarbon belts including fully conjugated beltarenes and their (partially) saturated analogs have fascinated chemists for decades due to their aesthetic structures, tantalizing properties, and potential applications in supramolecular chemistry and carbon nanoscience and nanotechnology. However, synthesis of hydrocarbon belts still remains a formidable challenge. We report in this communication a general approach to hydrocarbon belts and their derivatives. Closing up all four fjords of resorcin[4]arene derivatives through multiple intramolecular Friedel-Crafts alkylation reactions in an operationally simple one-pot reaction manner enabled efficient construction of octohydrobelt[8]arenes. Synthesis of belt[8]arene from DDQ-oxidized aromatization of octohydrobelt[8]arene under different conditions resulted in aromatization and simultaneous [4 + 2] cycloaddition reactions with DDQ or TCNE to produce selectively tetrahydrobelt[8]arene-DDQ2, tetrahydrobelt[8]arene-TCNE2, and belt[8]arene-DDQ4 adducts. Formation of belt[8]arene, a fully conjugated hydrocarbon belt, was observed from retro-Diels-Alder reaction of a belt[8]arene-DDQ4 adduct with laser irradiation under MALDI conditions. The new and practical synthetic method established would open an avenue to create belt-shaped molecules from easily available starting materials.

15.
J Am Chem Soc ; 142(34): 14432-14436, 2020 08 26.
Artigo em Inglês | MEDLINE | ID: mdl-32786737

RESUMO

We report herein a strategy to construct enantiopure inherently chiral macrocycles, ABCD-type heteracalix[4]aromatics, through a catalytic enantioselective intramolecular C-N bond forming reaction. A chiral ligand-palladium complex was found to efficiently induce the inherent chirality of molecules during the macrocyclization process with ee values up to >99%. The resulting ABCD-type heteracalix[4]aromatics displayed excellent and pH-triggered switchable electronic circular dichroism and circularly polarized luminescence properties.


Assuntos
Calixarenos/síntese química , Complexos de Coordenação/química , Compostos Macrocíclicos/síntese química , Paládio/química , Calixarenos/química , Catálise , Concentração de Íons de Hidrogênio , Ligantes , Compostos Macrocíclicos/química , Estrutura Molecular , Estereoisomerismo
16.
Nat Mater ; 23(1): 29-30, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38129576
17.
Chemistry ; 26(2): 401-405, 2020 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-31602706

RESUMO

We report in this article a cascade reaction strategy for the synthesis of complex N-heterocyclic compounds with contiguous and tetrasubstituted stereogenic carbons. Under the sequential catalysis of a chiral binol-Ti complex and BF3 , cyclopentanone-derived tertiary enamides undergo an enantioselective enamine addition to ketone carbonyls followed by diastereoselective trapping of the resulting acyliminiums by electron-rich aryl moieties to furnish four- and five-membered ring-fused N-heterocyclic products as the sole diastereomers in high yields with up to 99 % ee.

18.
J Org Chem ; 85(20): 13211-13219, 2020 10 16.
Artigo em Inglês | MEDLINE | ID: mdl-33026225

RESUMO

We report herein an efficient cascade strategy for the rapid construction of a highly enantioenriched erythrinane core skeleton. Under the sequential catalysis of a chiral Cr(III)(salen)Cl and InCl3, cyclohexanone-derived tertiary enamides undergo an intramolecular enantioselective nucleophilic addition followed by diastereoselective Pictet-Spengler cyclization. This method is highly enantio- and diastereoselective, leading to diverse erythrina alkaloid derivatives as the sole diastereoisomer with up to 98% ee.

19.
J Org Chem ; 85(4): 2312-2320, 2020 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-31878781

RESUMO

A number of butadiynylene-strapped O6-corona[6]arenes were synthesized straightforwardly through intramolecular oxidative homocoupling of O6-corona[6]arenes, which contained at least two N-propargyl-phthalimide segments. The mono-macrocyclic reactants were prepared from the reaction between 3,6-dichlorotetrazine and N-propargyl-3,6-dihydroxyphthalimide and another 1,4-dihydroxybenzene derivative with roughly a 3:2:1.3-1.5 ratio in a one-pot reaction manner. The synthesized butadiynylene-strapped corona[3]arene[3]tetrazines acted as highly selective electron-deficient macrocyclic hosts to form 1:1 complexes with thiocyanate in solution, and the association constant (Ka) was up to 1390 M-1. The anion-π noncovalent interactions provided the driving force for host-guest complexation.

20.
Angew Chem Int Ed Engl ; 59(41): 18151-18155, 2020 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-32602229

RESUMO

Described in this paper are the synthesis and structure of novel and edge-functionalized zigzag hydrocarbon belts. A stepwise "fjord-stitching" strategy featuring repetitive intramolecular acylation reactions of a resorcin[4]arene derivative as the key steps afforded a biscarbonyl-functionalized octahydrobelt[8]arene product. Facile ketone reduction with NaBH4 and nucleophilic addition with n-butyllithium produced secondary and tertiary alcohol-containing molecular belts, respectively. Selective oxidation reactions of biscarbonyl-bearing octahydrobelt[8]arene with m-CPBA and (PhSeO)2 O furnished the corresponding lactone- and 1,4-quinone-embedded molecular belts. Depending on the functional groups on the edges, the acquired belt molecules adopt different shapes such as square prism, truncated cone, and elliptical cylinder.

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