Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 15 de 15
Filtrar
1.
Stem Cell Res Ther ; 15(1): 187, 2024 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-38937829

RESUMO

Due to the advanced studies on stem cells in developmental biology, the roles of stem cells in the body and their phenotypes in related diseases have not been covered clearly. Meanwhile, with the intensive research on the mechanisms of stem cells in regulating various diseases, stem cell therapy is increasingly being attention because of its effectiveness and safety. As one of the most widely used stem cell in stem cell therapies, hematopoietic stem cell transplantation shows huge advantage in treatment of leukemia and other blood-malignant diseases. Besides, due to the effect of anti-inflammatory and immunomodulatory, mesenchymal stem cells could be a potential therapeutic strategy for variety infectious diseases. In this review, we summarized the effects of Staphylococcus aureus (S. aureus) and its components on different types of adult stem cells and their downstream signaling pathways. Also, we reviewed the roles of different kinds of stem cells in various disease models caused by S. aureus, providing new insights for applying stem cell therapy to treat infectious diseases.


Assuntos
Staphylococcus aureus , Humanos , Animais , Inflamação/terapia , Infecções Estafilocócicas/terapia , Transdução de Sinais , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/metabolismo
2.
Biomed Pharmacother ; 170: 116039, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38157643

RESUMO

Renal fibrosis (RF) is the end stage of several chronic kidney diseases. Its series of changes include excessive accumulation of extracellular matrix, epithelial-mesenchymal transition (EMT) of renal tubular cells, fibroblast activation, immune cell infiltration, and renal cell apoptosis. RF can eventually lead to renal dysfunction or even renal failure. A large body of evidence suggests that natural products in traditional Chinese medicine (TCM) have great potential for treating RF. In this article, we first describe the recent advances in RF treatment by several natural products and clarify their mechanisms of action. They can ameliorate the RF disease phenotype, which includes apoptosis, endoplasmic reticulum stress, and EMT, by affecting relevant signaling pathways and molecular targets, thereby delaying or reversing fibrosis. We also present the roles of nanodrug delivery systems, which have been explored to address the drawback of low oral bioavailability of natural products. This may provide new ideas for using natural products for RF treatment. Finally, we provide new insights into the clinical prospects of herbal natural products.


Assuntos
Produtos Biológicos , Medicamentos de Ervas Chinesas , Nefropatias , Humanos , Medicina Tradicional Chinesa , Produtos Biológicos/farmacologia , Produtos Biológicos/uso terapêutico , Medicamentos de Ervas Chinesas/farmacologia , Medicamentos de Ervas Chinesas/uso terapêutico , Nefropatias/tratamento farmacológico , Fibrose , Sistemas de Liberação de Medicamentos
3.
Zhongguo Zhen Jiu ; 43(3): 294-8, 2023 Mar 12.
Artigo em Chinês | MEDLINE | ID: mdl-36858391

RESUMO

OBJECTIVE: To observe the clinical efficacy and safety of Jianpi Peiyuan acupoint thread embedding therapy on perimenopausal obesity (PMO). METHODS: Ninety-six patients of PMO were randomly divided into an observation group (48 cases) and a control group (48 cases). The control group received health education and lifestyle intervention. On the basis of the treatment in the control group, the observation group was treated with acupoint thread embedding at the main acupoints of Shangwan (CV 13), Zhongwan (CV 12), Xiawan (CV 10), Yinlingquan (SP 9) and Fenglong (ST 40), etc. as well as the supplementary acupoints in accordance with the syndrome differentiation, once every 2 weeks for 8 weeks (4 times in total). The indexes of obesity (body mass index [BMI], waist circumference, hip circumference and body mass), modified Kupperman score, insomnia severity index (ISI) score, self-rating anxiety scale (SAS) score, and self-rating depression scale (SDS) score of the two groups were observed before and after treatment, and the safety was evaluated. RESULTS: After treatment, BMI, waist circumference, hip circumference and body mass in the two groups were lower than before treatment (P<0.05), and those in the observation group were lower than the control group (P<0.05). After treatment, Kupperman, ISI and SAS scores in the observation group were lower than before treatment (P<0.05), and ISI score in the control group was lower than before treatment (P<0.05). Kupperman, ISI and SAS scores in the observation group were lower than those in the control group (P<0.05). There was no significant difference in SDS between the two groups or within groups (P>0.05). No serious adverse reactions occurred during the experiment. CONCLUSION: Jianpi Peiyuan acupoint thread embedding therapy can reduce the degree of obesity in PMO patients, and improve patients' the perimenopausal symptoms, insomnia and anxiety, with good safety.


Assuntos
Pontos de Acupuntura , Distúrbios do Início e da Manutenção do Sono , Humanos , Perimenopausa , Ansiedade , Obesidade
4.
Zhongguo Zhen Jiu ; 43(3): 299-303, 2023 Mar 12.
Artigo em Chinês | MEDLINE | ID: mdl-36858392

RESUMO

OBJECTIVE: To observe the effect of acupuncture at Weizhong (BL 40) with deqi on bladder urination function. METHODS: A total of 60 healthy subjects were randomized into an observation group and a control group, 30 subjects in each group. Under the guidance of ultrasound, acupuncture was applied Weizhong (BL 40) on both sides. In the observation group, the needling depth was reached to the tibial nerve, and lifting-thrusting twirling method was used to induce deqi. In the control group, the needling depth was reached to the superficial fascia, and no manipulation was operated to induce deqi. The needles were retained for 10 min and acupuncture was given once in both groups. The bilateral ureteral ejection frequency and volume of the bladder were observed by ultrasound before and after acupuncture, and the score of clinical evaluation scale of deqi sensation was observed in both groups. RESULTS: After acupuncture, the frequency of bilateral ureteral ejection in the observation group and the bladder volume in the two groups were increased compared before acupuncture (P<0.05), and the frequency of bilateral ureteral ejection, bladder volume and score of clinical evaluation scale of deqi sensation in the observation group were higher than those in the control group (P<0.05, P<0.01). CONCLUSION: Acupuncture at Weizhong (BL 40) with deqi improves the bladder urination function. Ultrasound visualization improves the standardization and safety of acupuncture, intuitively evaluates the acupuncture effect, and provides an objective basis for the correlation between meridian points specificity and zang-fu organs.


Assuntos
Terapia por Acupuntura , Meridianos , Humanos , Micção , Bexiga Urinária , Pontos de Acupuntura
5.
Artigo em Chinês | MEDLINE | ID: mdl-35300758

RESUMO

Objective To explore the interaction between abnormal prepregnancy body mass index(pBMI)and high blood lipid level during pregnancy on the risk of gestational diabetes mellitus(GDM). Methods A total of 235 patients with GDM and no blood lipid-related diseases before pregnancy were selected from Hangzhou Women's Hospital during March 2017 to July 2018 as the GDM group.At a ratio of 1∶3,a total of 705 individual age-matched pregnant women with normal glucose metabolism during prenatal examination from the same hospital were selected as the control group.The generalized multifactor dimension reduction(GMDR)method was employed to characterize the possible interaction between pBMI-blood lipid and GDM.The cross-validation consistency,equilibrium test accuracy,and P value were calculated to evaluate the interaction of each model. Results GMDR model analysis showed that the second-order model including pBMI and gestational blood lipid level had the best performance(P=0.001),with the cross-validation consistency of 10/10 and the equilibrium test accuracy of 64.48%,suggesting that there was a potential interaction between pBMI and gestational high blood lipid level.After adjustment of confounding factors,the model demonstrated that overweight/obesity patients with high triglyceride(TG) level had the highest risk of developing GDM(OR=14.349,95%CI=6.449-31.924,P<0.001).Stratified analysis showed that overweight/obesity patients under high TG level group had a higher risk of developing GDM than normal weight individuals(OR=2.243,95%CI=1.173-4.290,P=0.015). Conclusions Abnormal pBMI and high blood lipid level during pregnancy are the risk factors of GDM and have an interaction between each other.Overweight/obese pregnant women with high TG levels are more likely to develop GDM.


Assuntos
Diabetes Gestacional , Hiperlipidemias , Índice de Massa Corporal , Feminino , Humanos , Hiperlipidemias/complicações , Obesidade/complicações , Sobrepeso , Gravidez
6.
Zhonghua Nan Ke Xue ; 28(12): 1123-1128, 2022 Dec.
Artigo em Chinês | MEDLINE | ID: mdl-37846634

RESUMO

In recent years, the incidence of PCa in China has been increasing year by year. Early diagnosis of the malignancy and monitoring of its progression are keys to the reduction of mortality. Currently, early diagnosis of PCa is mainly achieved by determining the level of PSA. Due to the insufficient specificity of PSA, definite diagnosis necessitates needle biopsy, which, as an invasive procedure, causes injury to the patients. Therefore biomarkers seem to be a significant option for the improvement of diagnostic accuracy. Exosomes are 30-150 nm extracellular vesicles secreted by various types of cells in normal and pathological conditions and exist stably in circumcision. Studies show that exosomes contain miRNAs and proteins critical to the progression and metastasis of PCa and have a great potential in the diagnosis of the malignancy. This review outlines the advances in the application of exosomes as novel biomarkers in the diagnosis of PCa.


Assuntos
Exossomos , MicroRNAs , Neoplasias da Próstata , Masculino , Humanos , Antígeno Prostático Específico/metabolismo , Biomarcadores Tumorais/metabolismo , Neoplasias da Próstata/patologia
7.
Biomed Environ Sci ; 34(9): 705-718, 2021 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-34530960

RESUMO

OBJECTIVE: The effects of interactions between genetic and environmental factors on the noise-induced hearing loss (NIHL) are still unclear. This study aimed to assess interactions among gene polymorphisms, noise metrics, and lifestyles on the risk of NIHL. METHODS: A case-control study was conducted using 307 patients with NIHL and 307 matched healthy individuals from five manufacturing industries. General demographic data, lifestyle details, and noise exposure levels were recorded. The Kompetitive allele-specific polymerase chain reaction (KASP) was used to analyze the genotypes of 18 SNPs. RESULTS: GMDR model demonstrated a relevant interaction between NRN1 rs3805789 and CAT rs7943316 (P = 0.0107). Subjects with T allele of rs3805789 or T allele of rs7943316 had higher risks of NIHL than those with the SNP pair of rs3805789-CC and rs7943316-AA (P < 0.05). There was an interaction among rs3805789, rs7943316, and kurtosis (P = 0.0010). Subjects exposed to complex noise and carrying both rs3805789-CT and rs7943316-TT or rs3805789-CT/TT and rs7943316-AA had higher risks of NIHL than those exposed to steady noise and carrying both rs3805789-CC and rs7943316-AA (P < 0.05). The best six-locus model involving NRN1 rs3805789, CAT rs7943316, smoking, video volume, physical exercise, and working pressure for the risk of NIHL was found to be the interaction (P = 0.0010). An interaction was also found among smoking, video volume, physical exercise, working pressure, and kurtosis (P = 0.0107). CONCLUSION: Concurrence of NRN1 and CAT constitutes a genetic risk factor for NIHL. Complex noise exposure significantly increases the risk of NIHL in subjects with a high genetic risk score. Interactions between genes and lifestyles as well as noise metrics and lifestyles affect the risk of NIHL.


Assuntos
Catalase/genética , Perda Auditiva Provocada por Ruído/genética , Neuropeptídeos/genética , Adulto , Estudos de Casos e Controles , Feminino , Proteínas Ligadas por GPI/genética , Predisposição Genética para Doença , Humanos , Masculino , Polimorfismo de Nucleotídeo Único
8.
J Clin Psychiatry ; 82(3)2021 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-34004092

RESUMO

BACKGROUND: Some previous studies have shown that weight gain is associated with greater improvement in psychopathology during antipsychotic treatment in patients with chronic schizophrenia. However, the results are mixed due to many confounding factors. The current study aimed to investigate whether weight gain was associated with antipsychotic response in patients with antipsychotic-naive and first-episode (ANFE) DSM-IV--diagnosed schizophrenia. METHODS: 526 ANFE patients and 313 healthy controls were enrolled in this study, which was conducted from January 2012 to December 2018. Treatment outcome was measured by the Positive and Negative Syndrome Scale (PANSS) at baseline and follow-up. Weight was measured at baseline and at the end of 8 weeks. RESULTS: After treatment, PANSS scores were significantly reduced as follows: positive symptoms (-10.40; 95% CI, -9.31 to -10.60), negative symptoms (-5.01; 95% CI, -4.43 to -5.54), general psychopathology (-13.01; 95% CI, -12.01 to -14.01), and PANSS total score (-28.53; 95% CI, -26.73 to -30.33). In addition, the average weight of ANFE patients increased by 2.89 kg (95% CI, 2.55 to 3.22), although it was still lower than the average weight of healthy controls. The proportion of patients with weight gain ≥ 7% after treatment was 38.2%. Weight gain was positively associated with decrease of PANSS positive symptoms, general psychopathology, and total score (all P < .05). Multiple linear regression analysis showed that baseline weight, decrease of PANSS total score, and sex were significantly associated with weight gain after treatment. CONCLUSIONS: Our findings suggest that there is a significant association between weight gain and improvement of clinical symptoms after 8 weeks of antipsychotic treatment in patients with ANFE schizophrenia. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT04076371.


Assuntos
Antipsicóticos/farmacologia , Avaliação de Resultados em Cuidados de Saúde , Esquizofrenia/tratamento farmacológico , Esquizofrenia/fisiopatologia , Aumento de Peso/efeitos dos fármacos , Adulto , Antipsicóticos/administração & dosagem , Antipsicóticos/efeitos adversos , Feminino , Seguimentos , Humanos , Masculino , Estudos Prospectivos , Escalas de Graduação Psiquiátrica , Índice de Gravidade de Doença , Adulto Jovem
9.
J Int Med Res ; 48(8): 300060520945895, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32812467

RESUMO

Cardiac tamponade is a rare complication that occurs during hemihepatectomy. This particular complication has a high degree of mortality and morbidity. A 51-year-old woman was admitted to our hospital for surgical treatment of a malignant liver tumor. During surgery, she developed sudden hemodynamic instability and signs suggesting cardiac tamponade, which was confirmed via transthoracic echocardiogram. Cardiac compression and creation of a pericardial window resulted in immediate hemodynamic improvement. At completion of surgery, a repeated transthoracic echocardiogram showed no pericardial effusion. Early ultrasound-assisted diagnosis and treatment of cardiac tamponade are crucial. Although cardiac tamponade rarely occurs during hemihepatectomy, medics should be aware of this possibility to ensure prompt diagnosis. Our findings strongly support the use of early cardiac compression in cardiac arrest during surgery with echocardiography for prompt and accurate diagnosis of cardiac tamponade. Additionally, our findings will hopefully make anesthesiologists aware of the need to maintain a high index of suspicion for cardiac tamponade with sudden hypotension and a large reduction in differential pressure, and encourage early use of echocardiography and timely cardiac compression.


Assuntos
Tamponamento Cardíaco , Derrame Pericárdico , Tamponamento Cardíaco/diagnóstico por imagem , Tamponamento Cardíaco/etiologia , Ecocardiografia , Feminino , Coração , Humanos , Pessoa de Meia-Idade , Derrame Pericárdico/diagnóstico por imagem , Derrame Pericárdico/etiologia , Ultrassonografia
10.
Transl Psychiatry ; 10(1): 18, 2020 01 21.
Artigo em Inglês | MEDLINE | ID: mdl-32066717

RESUMO

Accumulating studies have revealed gender differences in many aspects of schizophrenia (SZ), including obesity and cognitive function. The relationship between obesity and cognitive impairment in SZ has been studied before; however, the results are inconsistent. This study was designed to examine the sex differences in the relationship between body mass index (BMI) and cognitive deficits in Chinese patients with chronic SZ, which have not been investigated yet. 176 chronic patients with SZ (male/female = 108/68) and 200 controls (male/female = 120/80) were enrolled to compare the sex differences in cognitive functions measured by the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), BMI, and their associations. The clinical symptoms were evaluated using the positive and negative syndrome scales (PANSS). Our results showed that male patients had lower BMI and more negative symptoms but fewer positive symptoms than female patients (all p < 0.05). However, there was no significant sex difference in RBANS scores. In male patients, BMI was correlated with age of onset, PANSS general psychopathology, total score, negative symptom, together with RBANS language, visuospatial/construction, and attention. Further regression analysis showed that in male patients, BMI was significantly associated with RBANS language, PANSS general psychopathology, PANSS total score, and age of onset, with adjusted R2 = 0.22. These findings revealed significant sex differences in BMI, cognitive dysfunctions and their association in SZ. Nonetheless, these results should only be considered as preliminary because of the cross-sectional design, which will deserve further replication in first-episode patients using a prospective longitudinal design.


Assuntos
Disfunção Cognitiva , Esquizofrenia , Índice de Massa Corporal , China/epidemiologia , Cognição , Disfunção Cognitiva/epidemiologia , Estudos Transversais , Feminino , Humanos , Idioma , Masculino , Testes Neuropsicológicos , Estudos Prospectivos , Escalas de Graduação Psiquiátrica , Esquizofrenia/complicações , Esquizofrenia/epidemiologia , Psicologia do Esquizofrênico , Caracteres Sexuais
11.
Chin Med J (Engl) ; 131(9): 1059-1066, 2018 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-29692377

RESUMO

BACKGROUND: As a major complication after orthotopic liver transplantation (OLT), the occurrence of acute kidney injury (AKI) is frequently defined by serum creatinine (Cr); however, the accuracy of commonly used blood urea nitrogen (BUN), uric acid (UA), and ß2-microglobulin (ß2-MG) remains to be explored. This retrospective study compared the accuracy of these parameters for post-OLT AKI evaluation. METHODS: Patients who underwent OLT in three centers between July 2003 and December 2013 were enrolled. The postoperative AKI group was diagnosed by the Kidney Disease Improving Global Outcomes (KDIGO) criteria and classified by stage. Measurement data were analyzed using the t-test or Wilcoxon rank-sum test; enumerated data were analyzed using the Chi-square test or Fisher's exact test. Diagnostic reliability and predictive accuracy were evaluated using receiver operating characteristic (ROC) curve analysis. RESULTS: This study excluded 976 cases and analyzed 697 patients (578 men and 119 women); the post-OLT AKI incidence was 0.409. Compared with the no-AKI group, the AKI group showed very significant differences in Model for End-stage Liver Disease score (14.74 ± 9.91 vs. 11.07 ± 9.54, Z = 5.404; P < 0.001), hepatic encephalopathy (45 [15.8%] vs. 30 [7.3%], χ2 = 12.699; P < 0.001), hemofiltration (28 [9.8%] vs. 0 [0.0%], χ2 = 42.171; P < 0.001), and 28-day mortality (23 [8.1%] vs. 9 [2.2%], χ2 = 13.323; P <0.001). Moreover, mean values of Cr, BUN, UA, and ß2-MG in the AKI group differed significantly at postoperative days 1, 3, and 7 (all P < 0.001). ROC curve area was 0.847 of Cr for the detection of AKI Stage 1 (sensitivity 80.1%, specificity 75.7%, cutoff value 88.23 µmol/L), 0.916 for Stage 2 (sensitivity 87.6%, specificity 82.6%, cutoff value 99.9 µmol/L), and 0.972 for Stage 3 (sensitivity 94.1%, specificity 88.2%, cutoff value 122.90 µmol/L). CONCLUSION: The sensitivity and specificity of serum Cr might be a high-value indicator for the diagnosis and grading of post-OLT AKI.


Assuntos
Injúria Renal Aguda/sangue , Nitrogênio da Ureia Sanguínea , Creatinina/sangue , Transplante de Fígado , Ácido Úrico/sangue , Microglobulina beta-2/sangue , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos
12.
Acta Crystallogr Sect E Struct Rep Online ; 65(Pt 6): o1329, 2009 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-21583183

RESUMO

In the title compound, C(8)H(12)N(2)·H(2)O, four substituted pyridine mol-ecules alternate with four water mol-ecules, forming a large ring via O(water)-H⋯N(pyridine) and N(amine)-H⋯O(water) hydrogen bonding. Adjacent rings are connected via O(water)-H⋯O(water) hydrogen-bonds, forming a three-dimensional network.

13.
J Org Chem ; 69(19): 6221-7, 2004 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-15357579

RESUMO

Four oligoanthranilamides 1-4, which are incorporated with three, five, seven, or nine benzene units, respectively, have been synthesized and characterized. X-ray analysis, 1D and 2D (1)H NMR, and IR experiments reveal that all the new oligoamides adopt rigid, planar and zigzagged conformations in both solution and solid state, which are stabilized by intramolecular three-center hydrogen bonding. A 5-mer oligomer 22, which is incorporated with two acetylene groups at the ends, has also been synthesized and utilized for the self-assembly of a rigid hydrogen-bonded metallocyclophane. The new rigid oligoanthranilamides represent useful building blocks for the construction of supramolecular architectures.

14.
J Am Chem Soc ; 125(49): 15128-39, 2003 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-14653748

RESUMO

This paper describes the synthesis, self-assembly, and characterization of a new class of highly stable hydrazide-based quadruply hydrogen-bonded heterodimers. All of the hydrazide-derived heterodimers possess the complementary ADDA-DAAD hydrogen-bonding sequences. Hydrazide derivatives 1, which has two intramolecular S(6) RO.H-N hydrogen bonds, and 2 complex to afford two fastly exchanging isomeric heterodimers 1.2 and 1.2' in chloroform, as a result of two different conformational arrangements of 2. An average binding constant K(assoc) of 4.7 x 10(4) M(-)(1) was determined for heterodimer 1.2 and 1.2' by (1)H NMR titration of 1 with changing 2 in chloroform-d. In contrast, 1 binds 11 and 12, both of which are introduced with two intramolecular S(6) hydrogen bonds, to exclusively afford heterodimers 1.11 and 1.12, with K(assoc) values of 1.8 x 10(4) and 5.0 x 10(2) M(-)(1), respectively. Fluorine-containing 19, which has a hydrazide skeleton identical to that of 1 but two intramolecular S(6) F.H-N hydrogen bonds, can also complex with 2, 11, and 12, to afford heterodimers 19.2, 19.2', 19.11, and 19.12, with K(assoc) values of of 1.2 x 10(4) (average value for 19.2 and 19.2'), 5.4 x 10(3), and 1.9 x 10(2) M(-)(1), respectively. The structures of the new heterodimers have been proven with NOESY, IR, and VPO (for some of the heterodimers) experiments. Moreover, 1 and 19 can also strongly bind 2,7-dilauroylamido-1,8-naphthyridine 23 to afford dimers 1.23 and 19.23 with K(assoc) values of 6.0 x 10(5) and 1.4 x 10(5) M(-)(1), respectively. Adding 1 to the 1:1 solution of 23 and 1-octyl-3-(4-oxo-3,4-dihydro-pyrido[2,3-d]pyrimidin-2-yl)urea 24 or 1-octyl-3-(4-oxo-1,4-dihydro-pyrimidin-2-yl)urea 25, which had been developed initially by Zimmerman and Meijer, respectively, induces dimers 23.24 and 23.25 to dissociate, leading to the formation of dimers 1.23 and 24.24 or 25.25, respectively. The new hydrazide-based hydrogen-bonding modules described are useful building blocks for self-assembly and open a new avenue to recognition between discrete supramolecular species.

15.
Chemistry ; 9(12): 2904-13, 2003 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-12868422

RESUMO

A general method has been developed to control the selective rearrangement of Meijer's AADD quadruply hydrogen-bonded homodimers by introducing an additional donor-acceptor interaction. Therefore, one donor-assembling monomer, 1, in which the electron-rich bis(p-phenylene)-34-crown-10 moiety is connected to the hydrogen-bonding moiety, and two acceptor-assembling monomers, 2 and 3, in which the electron-deficient pyromellitic diimide or naphthalene diimide group is incorporated, respectively, are synthesized and characterized. 1H NMR and 2D-NOESY studies show that all these compounds exist as stable homodimers in chloroform. Mixing 1 equiv of 1 with 1 equiv of 2 in chloroform leads to the formation of heterodimers 1.2 in approximately 60 % yield, as a result of the electrostatic interaction between the bis(p-phenylene)-34-crown-10 moiety of 1 and the pyromellitic diimide group of 2. Selective formation of heterodimer 1.3 (>97 %) was achieved by mixing 1 equiv of 1 with 1 equiv of 3 in chloroform which resulted in a strengthened electrostatic interaction between the bis(p-phenylene)-[34]crown-10 moiety of 1 and the naphthalene diimide group of 3. The structures of heterodimers 1.2 and 1.3, which have been characterized by 1H NMR and UV/Vis experiments, reveal a remarkable promoting effect between the donor-acceptor interaction and intermolecular hydrogen-bonding. 1H NMR studies also reveal that heterodimers 1.2 and 1.3 can be fully and partially dissociated by addition of heterocycle 29, leading to the formation of new more robust heterodimers 1.29 and 2.29, or 3.29,respectively, and partially regenerated by subsequent addition of heterocyclic compound 30 through the formation of a new heterodimer 29.30. Heterodimers 1.2 and 1.3 represent a novel class of pseudo[2]rotaxanes constructed by two different noncovalent interactions.


Assuntos
Éteres Cíclicos/síntese química , Compostos Heterocíclicos/síntese química , Compostos Policíclicos/síntese química , Alcinos/síntese química , Alcinos/química , Materiais Biomiméticos/síntese química , Materiais Biomiméticos/química , Éteres Cíclicos/química , Compostos Heterocíclicos/química , Ligação de Hidrogênio , Imidas/síntese química , Imidas/química , Espectroscopia de Ressonância Magnética , Compostos Policíclicos/química , Rotaxanos , Espectrofotometria Ultravioleta
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...