RESUMEN
Propylene glycol alginate sodium sulfate (PSS) is a heparinoid polysaccharide drug used in clinic for >30 years in China. But its allergy events happened from time to time and should not be ignored. Here, ammonium salt in PSS (PSS-NH4+), PSS fractions with high Mw (PSS-H-Mw) and low mannuronic acid (M) to guluronic acid (G) ratio (PSS-L-M/G) were found to induce allergic response by the structure-activity and impurity-activity relationships in vitro. Furthermore, we confirmed the reason and elucidated the mechanism accounted for allergic side effect of PSS in vivo. It was found that high IgE levels in PSS-NH4+ and PSS-H-Mw groups upregulate the cascade expression of Lyn-Syk-Akt or Erk and second messenger Ca2+, which accelerated mast cells (MCs) degranulation to release histamine, LTB4, TPS, and finally induced lung tissue injury. PSS-L-M/G caused a mild allergic symptom because it only enhanced the expression of p-Lyn and histamine release. In brief, PSS-NH4+ and PSS-H-Mw were main reasons to result in allergic response. Our results suggested that it is very necessary to control the range of Mw and the content of impurities (< 1 % ammonium salt) of PSS to guarantee its safety and effectiveness in clinical treatment.
Asunto(s)
Compuestos de Amonio , Hipersensibilidad , Humanos , Alginatos/farmacología , Polisacáridos/farmacología , Hipersensibilidad/tratamiento farmacológico , MastocitosRESUMEN
Hematopoietic damage is a serious side effect of cytotoxic drugs, and agents promoting hematopoiesis are quite important for decreasing the death rate in cancer patients. In our previous work, we prepared the simulated digestive product of fucoidan from Sargassum fusiforme, DSFF, and found that DSFF could activate macrophages. However, more investigations are needed to further evaluate whether DSFF could promote hematopoiesis in the chemotherapy process. In this study, the protective effect of DSFF (1.8-7.2 mg/kg, i.p.) on cyclophosphamide-induced hematopoietic damage in mice and the underlying mechanisms were investigated. Our results show that DSFF could restore the numbers of white blood cells, neutrophils, and platelets in the peripheral blood, and could also retard bone marrow cell decrease in mice with cyclophosphamide-induced hematopoietic damage. UPLC/Q-Extraction Orbitrap/MS/MS-based lipidomics results reveal 16 potential lipid biomarkers in a serum that responded to hematopoietic damage in mice. Among them, PC (20:1/14:0) and SM (18:0/22:0) were the key lipid molecules through which DSFF exerted protective actions. In a validation experiment, DSFF (6.25-100 µg/mL) could also promote K562 cell proliferation and differentiation in vitro. The current findings indicated that DSFF could affect the blood cells and bone marrow cells in vivo and thus showed good potential and application value in alleviating the hematopoietic damage caused by cyclophosphamide.
Asunto(s)
Ciclofosfamida/toxicidad , Hematopoyesis/efectos de los fármacos , Agonistas Mieloablativos/toxicidad , Polisacáridos/farmacología , Sustancias Protectoras/farmacología , Sargassum , Animales , Biomarcadores/sangre , Médula Ósea/efectos de los fármacos , Médula Ósea/metabolismo , Proliferación Celular/efectos de los fármacos , ADN/metabolismo , Humanos , Células K562 , Recuento de Leucocitos , Lipidómica , Ratones , Neutrófilos/efectos de los fármacos , Recuento de PlaquetasRESUMEN
Molecular size and spatial structure affect the bioactivities of polysaccharides. SFF is a fucoidan extracted from Sargassum fusiforme. The possible changes of SFF affected by gastrointestinal tract and subsequently changes of its physicochemical property or its bioactivity have yet to be systematically investigated. Our results showed that DSFF, the gastrointestinal digestion product of SFF, has increased reducing sugar content, increased proportion of low molecular weight components, and a more clustered island-like morphology. Both SFF and DSFF activate RAW 264.7 macrophages evidenced by the increasing level of NO, intracellular ROS, and macrophages cytokines. Further investigation showed that DSFF induced M1 phenotype polarization in RAW 264.7 cells. DSFF also showed stronger macrophage activation and phenotype polarization than SFF. Our present work showed that SFF could be digested by simulated gastrointestinal environment in vitro and the digested product DSFF showed higher efficiency in macrophages activation and phenotype polarization.
Asunto(s)
Activación de Macrófagos , Polisacáridos , Sargassum , Animales , Digestión/efectos de los fármacos , Microbioma Gastrointestinal/efectos de los fármacos , Ratones , Peso Molecular , Células RAW 264.7RESUMEN
BACKGROUND: Lung cancer has the highest morbidity and mortality in the world and novel treatment strategies are still needed. Haimufang decoction (HMF) is a patented clinical prescription of traditional Chinese medicine for lung cancer treatment. HMF is composed of four herbs and has been applied clinically in advanced cancer patients. However, its therapeutic mechanisms are still unclear. This study aims to elucidate the possible mechanisms of HMF for the treatment of lung cancer. METHODS: 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide assay was applied for evaluating the proliferative effect of HMF in lung cancer cells and monocyte macrophage RAW264.7 cells. Flow cytometer was used to detect the effects of HMF on cell cycle and apoptosis, and western blotting was employed to explore the potential apoptotic mechanisms of HMF on lung cancer cells. For immunomodulatory effect, co-culture system was used to detect the activation of macrophage RAW264.7 cells when treated with HMF, and neutral red assay was used to measure the effect of HMF on the phagocytosis of the activated macrophages. Enzyme linked immunosorbent assay, flow cytometer, and immunofluorescence staining method were employed for the investigation on the underlying mechanisms of the immunomodulatory effect on RAW264.7 induced by HMF. RESULTS: HMF inhibited the proliferation, induced S phase cell cycle arrest, and stimulated apoptosis in lung cancer NCI-H1975 cells, while had negligible cytotoxicity on macrophage RAW264.7 cells. Moreover, HMF could activate macrophage RAW264.7 cells and promote the inhibition activity of RAW264.7 cells against lung cancer cells. And also, HMF activated macrophages and increased their phagocytic activity in a concentration-dependent manner. HMF increased the expression of macrophage activation marker CD40, the level of nitric oxide, the generation of intracellular reactive oxygen species, as well as M1 macrophages cytokines including tumor necrosis factor-α, interleukin-1ß, interleukin 12 p70, and interleukin 6. Further investigation showed that HMF induced M1 but not M2 phenotype polarization in RAW264.7 cells. CONCLUSIONS: HMF can mainly exert anticancer activity via (1) cytotoxicity to human lung cancer cells by proliferation inhibition, cell cycle arrest, and apoptosis induction; and also via (2) immunomodulation via macrophage cells activation and M1 phenotype polarization induction.
Asunto(s)
Antineoplásicos/farmacología , Apoptosis/efectos de los fármacos , Puntos de Control del Ciclo Celular/efectos de los fármacos , Medicamentos Herbarios Chinos/farmacología , Neoplasias Pulmonares/tratamiento farmacológico , Macrófagos/efectos de los fármacos , Animales , Línea Celular Tumoral , Humanos , Ratones , Células RAW 264.7RESUMEN
OBJECTIVE: To study the value of serum gamma-glutamyl transpeptidase (GGT) combined with direct bilirubin (DB) in the diagnosis of biliary atresia. METHODS: A total of 667 infants with cholestasis who were hospitalized and treated from July 2010 to December 2018 were enrolled as subjects. According to the results of intraoperative cholangiography and follow-up, they were divided into biliary atresia group with 234 infants and cholestasis group with 433 infants. The two groups were compared in terms of age of onset, sex, and serum levels of total bilirubin (TB), DB, alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bile acid (TBA), and GGT. A receiver operating characteristic (ROC) curve analysis was performed for indices with statistical significance, and the area under the ROC curve (AUC) and the optimal cut-off value for diagnosis were calculated. RESULTS: The biliary atresia group had a significantly younger age of onset than the cholestasis group (P<0.001). There were no significant differences in sex, ALT, and AST between the two groups (P>0.05), while the biliary atresia group had significantly higher serum levels of TB, DB, TBA, and GGT than the cholestasis group (P<0.05). GGT combined with DB had the highest AUC of 0.892 (95% confidence interval: 0.868-0.916) in the diagnosis of biliary atresia. At the optimal cut-off values of 324.0 U/L for GGT and 115.1â µmmol/L for DB, GGT combined with DB had a sensitivity of 79.8% and a specificity of 83.2% in the diagnosis of biliary atresia. CONCLUSIONS: GGT combined with DB has high sensitivity and specificity in the diagnosis of biliary atresia and can be used as an effective indicator for diagnosis of biliary atresia in infants.
Asunto(s)
Atresia Biliar , gamma-Glutamiltransferasa/sangre , Alanina Transaminasa , Aspartato Aminotransferasas , Atresia Biliar/diagnóstico , Bilirrubina , Humanos , LactanteRESUMEN
The photosynthesis response of the leaves of 2-year-old potted Dendrocalamopsis oldhami seedlings under continuous and multistage soil moisture was measured and analyzed by using a porta-ble photosynthetic system (Li-6400) during the natural water consumption process from artificial watering to saturated soil water. The results showed that there was less obvious photoinhibition in leaves of D. oldhami grown in the region where the relative soil water content (SRWC) was from 53.5% to 95.6%. There was a higher net photosynthetic rate in relative water deficit environment with the relative soil water content from 53.5% to 69.6%. When SRWC was below 33.6%, there was a significant photoinhibition. When the relative soil water changed, the Pn max value simulated by rectangular hyperbola model was much higher than measured value. The simulated light saturation point (LSP) value fitted by the rectangular hyperbola model, the non-rectangular hyperbola model and the exponential model was much lower than the measured value, and the simulation of the light-response curve under extreme water shortage conditions had larger differences between the fitted values and the observed data. Both the stomatal limitation value (Ls) and water use efficiency (WUEinst) showed a similar response process as the relative soil water decreased. Both of them increased first and then decreased, with the maximum value appeared in the range of 53.5%≤SRWC≤69.6%. Such a result showed a similarity and representative with the Pn max of photosynthesis light-response processes under changing soil moisture. The optimal humidity management range of SRWC for normal photosynthesis in leaves of D. oldhami was from 53.5% to 69.6%. In addition, it had good adaptability to higher soil water content (69.6%≤SRWC≤95.6%). Rectangular hyperbola modified model could well simulate the light-response of photosynthesis under different soil water conditions (23.1%≤SRWC≤95.6%), while the other three models had their own limitations.
Asunto(s)
Bambusa/fisiología , Luz Solar , Agua , Fotosíntesis , Hojas de la Planta , SueloRESUMEN
AIM: To investigate the specific biomarkers and potential pathogenesis of colorectal cancer-related ischemic stroke (CRCIS). METHODS: A retrospective study was conducted on CRCIS patients (colorectal cancer patients with ischemic stroke without conventional stroke risk factors) registered at seven centers between January 2007 and December 2017. Clinical data and laboratory and imaging findings were compared with age- and sex- matched patients with colorectal cancer (CRC) without ischemic stroke that were admitted to the same hospital during the same period. Univariate and multivariate analyses were performed to analyze the independent risk factors for CRCIS. A receiver operator characteristic curve was configured to calculate the optimal cut-off value of the products of the independent risk factors for CRCIS. RESULTS: A total of 114 CRCIS patients and 114 CRC patients were included. Multiple lesions in multiple vascular territories were common in CRCIS patients (71, 62.28%). The levels of plasma D-dimer, carcinoembryonic antigen (CEA), cancer antigen 125, and neutrophil count were significantly higher in CRCIS patients than in CRC patients. Multiple logistic regression analysis revealed that plasma D-dimer levels [odds ratio (OR) = 1.002, 95% confidence interval (CI): 1.001-1.003, P < 0.001], CEA levels (OR = 1.011, 95%CI: 1.006-1.015, P < 0.001), and neutrophil count levels (OR = 1.626, 95%CI: 1.268-2.087, P < 0.001) were independent risk factors for CRCIS. In addition, receiver operator characteristic curve revealed that the area under curve for the products of plasma D-dimer, CEA, and neutrophil count was 0.889 ± 0.022 (95%CI: 0.847-0.932, P < 0.001), and the optimal cut-off value for the product was 252.06, which was called the CRCIS Index, with a sensitivity of 86.0% and specificity of 79.8%. CONCLUSION: Hypercoagulability induced by elevated CEA and neutrophils may be an important cause of CRCIS. The CRCIS index, which serves as a biomarker of CRCIS, needs further study.
Asunto(s)
Isquemia Encefálica/etiología , Antígeno Carcinoembrionario/sangre , Neoplasias Colorrectales/complicaciones , Neutrófilos , Accidente Cerebrovascular/etiología , Trombofilia/etiología , Anciano , Isquemia Encefálica/sangre , Isquemia Encefálica/diagnóstico , Antígeno Carcinoembrionario/metabolismo , Neoplasias Colorrectales/sangre , Femenino , Proteínas Ligadas a GPI/sangre , Proteínas Ligadas a GPI/metabolismo , Humanos , Recuento de Leucocitos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Factores de Riesgo , Accidente Cerebrovascular/sangre , Accidente Cerebrovascular/diagnóstico , Trombofilia/patologíaRESUMEN
Propylene glycol alginate sodium sulfate (PSS), a sulfated polysaccharide derivative, has been used as a heparinoid drug to prevent and treat hyperlipidemia and ischemic cardio-cerebrovascular diseases in China for 30 years. But its bleeding risk should not be overlooked. Here we clarified the reasons and mechanism leading to bleeding side effect of PSS. It was found that PSS fractions with low mannuronic acid (M)/guluronic acid (G) ratio and high molecular weight (Mw) can excessively extend activated partial thromboplastin time (APTT) and thrombin time (TT), over-inhibit the thrombin (FIIa) activity mediated by anti-thrombin III (ATIII) to induce bleeding risk. In addition, the fraction of low M/G ratio can suppress platelet aggregation mediated by adenosine diphosphate (ADP) and induce platelet reduction by improving platelet antibody (PA)-IgA/G in serum and by inhibiting or damaging the bone marrow hematopoietic function. And the fraction of high Mw can restrain the reticulated platelet (RP) production, then reduce mean platelet volume (MPV) and platelet-large cell counts or ratio, and finally decrease platelet amount by inhibiting or damaging the bone marrow hematopoietic function. In brief, PSS fractions with low M/G ratio and high Mw were the main reasons to bring about bleeding by excessively suppressing coagulant factors activities and weakening platelet function. Our results suggested that it is very necessary to control the M/G ratio and the range of Mw of PSS to guarantee its safety and effectiveness in clinical.
Asunto(s)
Alginatos/efectos adversos , Anticoagulantes/efectos adversos , Hemorragia/tratamiento farmacológico , Polisacáridos/efectos adversos , Sulfatos/efectos adversos , Alginatos/química , Alginatos/farmacología , Animales , Anticoagulantes/química , Anticoagulantes/farmacología , Pruebas de Coagulación Sanguínea , Conformación de Carbohidratos , Femenino , Masculino , Ratones , Ratones Endogámicos , Agregación Plaquetaria/efectos de los fármacos , Polisacáridos/química , Polisacáridos/farmacología , Ratas , Ratas Wistar , Sulfatos/química , Sulfatos/farmacologíaRESUMEN
Propylene glycol alginate sodium sulfate (PSS), a sulfated polysaccharide derivative, has been used as a heparinoid drug to prevent and treat hyperlipidemia and ischemic cardio-cerebrovascular diseases in China for nearly 30 years. To extend the applications of PSS, a series of low-molecular-weight PSSs (named FPs) were prepared by oxidative-reductive depolymerization, and the antithrombotic activities were investigated thoroughly in vitro and in vivo. The bioactivity evaluation demonstrated a positive correlation between the molecular weight and the anticoagulant and antithrombotic activities of FPs. FPs could prolong the APTT and clotting time and reduce platelet aggregation significantly. FPs could also effectively inhibit factor IIa in the presence of AT-III and HC-II. FPs decreased the wet weights and lengths of the thrombus and increased occlusion times in vivo. FP-6k, a PSS fragment with a molecular weight of 6 kDa, is an optimal antithrombotic candidate for further study and showed little chance for hemorrhagic action.
Asunto(s)
Alginatos/farmacología , Anticoagulantes/farmacología , Fibrinolíticos/farmacología , Hemorragia/prevención & control , Sulfatos/farmacología , Trombosis/tratamiento farmacológico , Alginatos/síntesis química , Alginatos/química , Animales , Anticoagulantes/síntesis química , Anticoagulantes/química , Pruebas de Coagulación Sanguínea , Relación Dosis-Respuesta a Droga , Fibrinolíticos/síntesis química , Fibrinolíticos/química , Masculino , Ratones , Ratones Endogámicos , Estructura Molecular , Peso Molecular , Agregación Plaquetaria/efectos de los fármacos , Ratas , Ratas Wistar , Relación Estructura-Actividad , Sulfatos/síntesis química , Sulfatos/químicaRESUMEN
Pigs are susceptible to both human and avian influenza viruses and therefore have been proposed to be mixing vessels for the generation of pandemic influenza viruses through reassortment. In this study, for the first time, we report the isolation and genetic analyses of three novel triple-reassortant H1N1 swine influenza viruses from pigs in Tianjin, Northern China. Phylogenetic analysis showed that these novel viruses contained genes from the 2009 pandemic H1N1 (PB2, PB1, PA and NP), Eurasian swine (HA, NA and M) and triple-reassortant swine (NS) lineages. This indicated that the reassortment among the 2009 pandemic H1N1, Eurasian swine and triple-reassortant swine influenza viruses had taken place in pigs in Tianjin and resulted in the generation of new viruses. Furthermore, three human-like H1N1, two classical swine H1N1 and two Eurasian swine H1N1 viruses were also isolated during the swine influenza virus surveillance from 2009 to 2013, which indicated that multiple genetic lineages of swine H1N1 viruses were co-circulating in the swine population in Tianjin, China. The emergence of novel triple-reassortant H1N1 swine influenza viruses may be a potential threat to human health and emphasizes the importance of further continuous surveillance.
Asunto(s)
Subtipo H1N1 del Virus de la Influenza A/aislamiento & purificación , Infecciones por Orthomyxoviridae/veterinaria , Virus Reordenados/aislamiento & purificación , Enfermedades de los Porcinos/virología , Animales , China , Genes Virales/genética , Subtipo H1N1 del Virus de la Influenza A/clasificación , Subtipo H1N1 del Virus de la Influenza A/genética , Infecciones por Orthomyxoviridae/virología , Filogenia , ARN Viral/genética , Virus Reordenados/clasificación , Virus Reordenados/genética , PorcinosRESUMEN
OBJECTIVE: Lifestyle changes have led to an increasing incidence of acute pancreatitis (AP) in China. The aims of this study were to evaluate the association between lifestyle as well as medical history and AP in the elderly population and to provide evidence towards the prevention against AP. METHODS: A population-based cross-sectional study was conducted in Daqing, Heilongjiang Province, China. A total of 23 294 residents aged ≥55 years were enrolled in the study. A questionnaire survey was conducted to collect data on participants' characteristics, lifestyle and medical history via a face-to-face interview, and compared these data with the medical chart. RESULTS: In total, 45 participants had been diagnosed with AP, that is, a prevalence of 0.19%. No significant differences were observed with respect to their age, gender, marital status or body mass index (BMI) in participants with and without AP. However, those were better educated were more likely to develop AP (P = 0.005). The univariate analysis showed that a high meat intake, smoking, alcohol consumption and a medical history of gallstones were associated with a significant increase in the risk of developing AP (P < 0.05). Furthermore, smoking or alcohol consumption was dose-dependently associated with the risk of AP, particularly in those who smoked at least 15 pack-years or consumed ≥56.2 drinks per year. Multivariable logistics analysis suggested that the level of education, smoking and medical history of gallstone are independent risk factors for AP. CONCLUSIONS: Our study indicated that a higher education level, smoking, alcohol consumption and history of gallstones may be potential risk factors for AP in the elderly in northeast China.
Asunto(s)
Pancreatitis/etiología , Enfermedad Aguda , Distribución por Edad , Anciano , Consumo de Bebidas Alcohólicas/efectos adversos , Consumo de Bebidas Alcohólicas/epidemiología , China/epidemiología , Estudios Transversales , Dieta/efectos adversos , Dieta/estadística & datos numéricos , Femenino , Cálculos Biliares/complicaciones , Cálculos Biliares/epidemiología , Humanos , Estilo de Vida , Masculino , Persona de Mediana Edad , Pancreatitis/epidemiología , Factores de Riesgo , Distribución por Sexo , Fumar/efectos adversos , Fumar/epidemiologíaRESUMEN
This study was aimed at developing a sensitive and selective HPLC method with postcolumn fluorescence derivatization for the detection of propylene glycol alginate sodium sulfate (PSS) in rat plasma. Plasma samples were prepared by a simple and fast ultrafiltration method. PSS was extracted from rat plasma with D-glucuronic acid as internal standard. Isocratic chromatographic separation was performed on a TSKgel G2500 PWxL column with the mobile phase of 0.1 M sodium sulfate at a flow rate of 0.5 mL/min. Analyte detection was achieved by fluorescence detection (FLD) at 250 nm (excitation) and 435 nm (emission) using guanidine hydrochloride as postcolumn derivatizing reagent in an alkaline medium at 120 °C. The calibration curve was linear over a concentration range of 1-500 µg/mL, and the lower limit of detection (LLOD) was found to be 250 ng/mL. This validated method was applied successfully to the pharmacokinetic study of PSS and PSS-loaded poly lactic-co-glycolic acid (PLGA) nanoparticles (PSS-NP) in rat plasma after a single intravenous (PSS only) and oral administration (PSS and PSS-NP). Significant differences in the main pharmacokinetic parameters of PSS and PSS-NP were observed. The relative bioavailability of PSS-NP was 190.10% compared with PSS which shows that PSS-NP can improve oral bioavailability.
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Alginatos/farmacocinética , Cromatografía Líquida de Alta Presión/métodos , Ácido Láctico/química , Nanopartículas , Ácido Poliglicólico/química , Administración Oral , Alginatos/análisis , Alginatos/química , Animales , Disponibilidad Biológica , Calibración , Femenino , Fluorescencia , Inyecciones Intravenosas , Límite de Detección , Masculino , Copolímero de Ácido Poliláctico-Ácido Poliglicólico , Ratas , Ratas Wistar , Sulfatos/químicaRESUMEN
AIM: The present study was designed to explore the radiation-resistance mechanism by interfering in checkpoints kinase 1 (CHK1) and DNA-activated protein kinase (DNA-PK) genes with short hairpin RNA (shRNA) transfection into Skov3 cells derived from ovarian cancer and HeLa cells derived from cervical cancer. MATERIALS AND METHODS: The cultured Skov3 and HeLa cells were transfected with plasmid vectors containing CHK1 shRNA and DNA-PK shRNA, respectively, through Lipofectimine™ 2000 mediation, and cultured for 20 hours before exposure to 2 Gy X-radiation. The cells were harvested 4 and 28 after X-irradiation respectively then washed 3 times with PBS. These cells were stained with Annexin V/PI and applied by flow cytometer to analyze alteration of apoptosis with software CellQuest. RESULTS: The apoptotic response in Skov3 cells to X-radiation was significantly lower than that in HeLa cells at 4 hour (t = 15.22, P < 0.001) and 28 hours (t = 15.78, P < 0.001) of post-irradiation. The shRNA might not affect the apoptosis of Skov3 and HeLa cells, while shRNA-transfection significantly enhanced the apoptotic response in Skov3 cells to X-radiation as compared with that in HeLa cells. CONCLUSIONS: The present work suggests that the CHK1 and DNA-PK genes are very likely to play a role in developing a radiation resistance in ovarian cancer.
Asunto(s)
Neoplasias Ováricas/genética , Tolerancia a Radiación/genética , Apoptosis/genética , Apoptosis/efectos de la radiación , Línea Celular Tumoral , Quinasa 1 Reguladora del Ciclo Celular (Checkpoint 1) , Proteína Quinasa Activada por ADN/genética , Proteína Quinasa Activada por ADN/metabolismo , Femenino , Células HeLa , Humanos , Neoplasias Ováricas/radioterapia , Proteínas Quinasas/genética , Proteínas Quinasas/metabolismo , Interferencia de ARN , Radiación , Rayos XRESUMEN
The Wittig reaction involving direct olefination of triphenylphosphonium ylides (Ph(3)P horizontal lineCHR) with aldehydes is arguably the most often used method for alkene synthesis, but in general it yields mixtures of Z- and E-alkenes for semistabilized triphenylphosphonium ylides (R = aryl or vinyl). We have developed a simple and efficient protocol to improve the stereoselectivity significantly by replacing the aldehydes used in the Wittig reaction with N-sulfonyl imines, which possess distinct electronic and steric properties relative to aldehydes. A broad range of aromatic, alpha,beta-unsaturated, and aliphatic imines bearing appropriate N-sulfonyl groups smoothly undergo olefination reaction with various benzylidenetriphenylphosphoranes or allylidenetriphenylphosphoranes under mild reaction conditions to afford an array of both Z- and E-isomers of conjugated alkenes in good to excellent yields and with greater than 99:1 stereoselectivity. Moreover, this tunable protocol has been successfully applied to the highly stereoselective synthesis of two anticancer agents, DMU-212 and its Z-isomer.
Asunto(s)
Alquenos/síntesis química , Iminas/química , Compuestos Organofosforados/química , Compuestos de Sulfhidrilo/química , Alquenos/química , Estructura Molecular , Compuestos Organofosforados/síntesis química , EstereoisomerismoRESUMEN
In the absence of external catalysts and additives, a broad range of benzylic and allylic alcohols react with various sulfinyl chlorides to afford structurally diversified benzylic and allylic sulfones in moderate to excellent yields, and importantly, a catalysis with byproduct HCl is involved in this new protocol for sulfone synthesis.
RESUMEN
The acid-catalyzed three-component reaction of terminal alkynes, benzylic alcohols, and simple arenes provides convenient and atom-economic access to an array of both Z- and E-isomers of trisubstituted alkenes with excellent stereoselectivity by switching reaction temperature and acidic catalysts.