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A new species of the firmoss from China, Huperziacrassifolia sp. nov., is described and illustrated based on morphological characters and molecular evidence. The new species resembles species associated with the H.javanica complex, in particular H.javanica based on leaf shape and serrations, but can be easily distinguished by elliptic lanceolate and thick coriaceous leaves, well differentiated seasonal constriction zones, and reflexed leaf margins when get dried. Phylogenomic reconstruction using whole chloroplast genome sequences recovered H.crassifolia as sister to H.sutchueniana and only distantly related to morphological similar species H.javanica, H.nanlingensis, and H.serrata. The genome size 2C = 17.2 pg indicated the new species to be a tetraploid, whereas diploid H.javanica had a genome size of 8.7 pg. Morphological characters, distribution, and conservation status of the new species are also presented.
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The effective and mild [4+1] annulation of ninhydrin-derived MBH carbonates with α,ß-unsaturated ketones has been developed, providing a wide range of multisubstituted furans in high yields (up to 90%) with excellent ß-regioselectivities. In contrast, the polysubstituted cyclopentenes bearing dispiro-bisindanedione motifs were obtained via classical [3+2] annulations by employing ninhydrin-derived MBH carbonates with 2-arylidene-1,3-indandiones under the same catalytic conditions. Furthermore, the structures of two kinds of cycloadducts were straightforwardly confirmed through X-ray diffraction analysis.
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A copper/cobalt-catalyzed difunctionalization of alkenes with sulfonylazides and tert-butyl hydroperoxide has been achieved. This protocol provides an efficient and direct oxysulfonylation approach to ß-ketosulfones and ß-sulfonyl peroxides in moderate to good yields under mild conditions. This methodology applies sulfonylazides as a new sulfonyl radical source and features a wide substrate scope and good functional group tolerance.
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Chronic fragmented sleep is a very common type of insomnia that affects the daily lives of numerous people around the world. However, its pathogenesis is not very clear and a corresponding rat model has not been reported for this purpose at present. The present study aimed to establish a rat model of chronic insomnia with sleep fragmentation using self-made multiple strings of unstable platforms surrounded by shallow water. During the establishment of the models, changes in body weight and differences in food and water intake in the daytime and at night were acquired. The rat models were assessed using several tests, including the Morris water maze test, pentobarbital sodium-induced sleep, infrared monitoring and electroencephalogram/electromyography during sleep. The expression levels of certain inflammatory factors and orexin A were detected in the serum and brain tissues using ELISAs, immunohistochemistry and immunofluorescence. The expression levels of orexin 1 receptor (orexin 1r) were also detected in the brain. Polysomnography indicated that the model rats were successfully prepared with reduced non-rapid eye movement (non-REM) sleep in the daytime, which was increased at night, and considerably lower REM duration during the day and night. The number of instances of sleep arousals were also increased in the day and at night, and the average duration of each sleep bout was decreased in the daytime. The body weights of the model rats increased at a normal rate. However, the reduction of body weight in the daytime and increased in body weight at night were significantly less than those of the control rats. The daytime food and water consumption of the model rats increased significantly compared with that of the control rats, but was similar to that of the control group at night. The Morris water maze test indicated that the model rats were slow to learn to escape the platforms and performed a lower number of target crossings. The pentobarbital-induced sleep experiment confirmed that the model rats exhibited a longer sleep latency and shorter sleep time. The serum IL-1ß, IL-6, TNF-α and orexin A levels of the model rats were significantly increased, whereas their serum IL-10 levels were significantly decreased compared with those of the control rats. The expression levels of IL-1ß, IL-6, orexin A and orexin 1r in the brain tissues of the model rats were also significantly increased. In conclusion, these data indicate that learning and memory function, sleep time, arousal times, diurnal and nocturnal body weight changes, food and water intake, and expression levels of the specific inflammatory factors orexin A and orexin 1r were altered in the model rats. This suggests the chronic insomnia rat model with sleep fragmentation was successfully established using multiple strings of unstable platforms surrounded by water.
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A highly selective and divergent synthesis which enabled access to various complex compounds is highly attractive in organic synthesis and medicinal chemistry. Herein, we developed an effective method for divergent synthesis of highly substituted tetrahydroquinolines via Lewis base catalyzed switchable annulations of Morita-Baylis-Hillman carbonates with activated olefins. The reaction displayed switchable [4 + 2] or [3 + 2] annulations via catalyst or substrate control, providing a diverse range of architectures which contained highly substituted tetrahydroquinolines or cyclopentenes with three contiguous stereocenters bearing a quaternary carbon center in high yields with excellent diastereoselectivities and regioselectivities. Furthermore, synthetic utility of this strategy was further highlighted by gram-scale experiments and simple transformations of the products.
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A simple and practical method for the construction of 1,3,5-trisubstituted imidazolidine derivatives via [3 + 2] cycloaddition reaction has been developed. This reaction could smoothly proceed between nonstabilized azomethine ylides generated in situ and 2-benzothiazolamines to deliver a wide scope of differently substituted imidazolidines in high yields (up to 98%). The structure of one example was confirmed by X-ray single-crystal structure analysis.
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A copper-catalyzed sulfonylation of alkynyl imines with sulfonyl hydrazides has been developed, which exhibited excellent regio- and stereoselectivity and furnished a series of (E)-ß-sulfonyl enones in moderate to good yields. Mechanistic studies suggest that this strategy goes through a radical process.
Assuntos
Cobre , Iminas , Catálise , HidrazinasRESUMO
Mild, convenient, and effective TBAI-catalyzed S-H and N-H insertion reactions of α-diazoesters with thiophenols and aromatic amines under metal-free conditions have been described, furnishing a straightforward and general platform for the synthesis of various thioethers and 2-amino-2-oxoacetates in moderate to excellent yields. Moreover, this strategy features simple operation, mild conditions, broad substrate scope, and easy scale-up.
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An effective synthetic method for 1,3,5-trisubstituted pyrazoles via 1,3-dipolar cycloaddition reaction has been developed. This reaction could smoothly proceed between ninhydrin-derived Morita-Baylis-Hillman carbonates and nitrilimines to provide a wide scope of differently substituted pyrazoles in high yields (up to 95%). In addition, the reaction mechanism was also proposed to explain its regioselectivity.
Assuntos
Iminas , Ninidrina , Carbonatos , Catálise , Reação de Cicloadição , Nitrilas , PirazóisRESUMO
To increase the solubility and targeting efficiency of curcumin (CCM) to tumors, transferrin (Tf)-CCM nanoparticles (NPs-CCM) with a CCM loading capacity of 5.2% were fabricated by Tf denaturation with hydrochloric acid, a denaturing agent, to open the hydrophobic cavity of Tf. The NPs-CCM were approximately 160 nm in size with a spherical shape. The solubility of the CCM in the nanoparticles was approximately 100,000 times greater than that of CCM alone (11 ng mL-1 vs 1.11 mg mL-1, respectively). The changes in the fluorescence spectra of Tf and 1-(anilinon)-aphthalene-8-sulfonic acid (ANS) in the NP-CCM preparation indicated that the polarity of certain hydrophobic and hydrophilic groups of Tf changed. CCM treatment of A549 cells resulted in a decrease in the mitochondrial membrane potential (MMP) and induced apoptosis through mitochondrial dependence. CCM increased the expression of phosphorylated c-Jun N-terminal kinase (JNK), P38, and extracellular signal-regulated kinase (ERK) but had a weak effect on the expression of nonphosphorylated JNK, P38, and ERK, which showed that the mitogen-activated protein kinase signaling (MAPK) transduction pathway is involved in CCM-mediated apoptosis. The half maximal inhibitory concentration (IC50) of NPs-CCM was higher than that of free CCM in A549 (16.41 ± 0.86 vs 12.51 ± 3.9 (µg mL-1), p = 0.036) and MCF-7 (9.31 ± 0.11 vs 2.44 ± 3.76 (µg mL-1), p < 0.0037) tumor cells, however the former had a greater tumor-targeting in vivo. Without the side effects of polyoxyethylene castor oil/ethanol as solvent, the hemolysis effect of NPs-CCM (0.05-1 mg mL-1) was notably lower than that of free CCM (p < 0.05). It was estimated that the half maximal lethal dose (LD50) of NPs-CCM was approximately two times that of CCM (100 mg kg-1 vs 50 mg kg-1), and the former had many advantages over that of free CCM in terms of lower toxicity and better targeting; thus, NPs-CCM can be administered at higher doses to acquire better antitumor effects than CCM alone, indicating that NPs-CCM are an effective and safe carrier for CCM delivery.
Assuntos
Curcumina , Nanopartículas , Curcumina/química , Interações Hidrofóbicas e Hidrofílicas , Nanopartículas/química , Solubilidade , Transferrina/químicaRESUMO
The additive-free [3 + 2] annulation from isatins, amino acids with 2-styrylbenzoxazoles, was described, providing a series of functional and structurally complex 3,3'-pyrrolidinyl-spirooxindole derivatives containing four contiguous and two quaternary stereogenic centers in high yields (up to 95%) and excellent diastereoselectivities (up to >25:1 dr). Interestingly, the reaction exhibits switchable regioselectivity depending on the substrate of amino acids. With proline or thioproline as the substrate, the reaction afforded α-regioselective spirooxindole skeletons. In contrast, when piperidine acid is the substrate, the reaction provided γ-regioselective spirooxindole skeletons.
Assuntos
Compostos de Espiro , Aminoácidos , Catálise , Indóis/química , Compostos de Espiro/química , EstereoisomerismoRESUMO
A CuI-catalyzed coupling reaction of benzofuran-3(2H)-ones with amines has been well established for the direct synthesis of α-ketoamides. This process involves C-O bond cleavage and C[double bond, length as m-dash]O/C-N bond formation. Mechanism studies indicated that this α-ketoamide formation reaction may involve a free radical process.
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A simple and efficient method for the synthesis of O-acylhydroxamate derivatives from oxime chlorides and carboxylic acids was developed. The reaction affords clean and facile access to diverse O-acylhydroxamates in high yields (up to 85%). The chemical structure of a typical product was confirmed using single-crystal X-ray structure analysis.
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A PIDA-promoted cross-dehydrogenative coupling reaction between N-hydroxyphthalimide (NHPI) and aryl ketones for efficient synthesis of N-alkoxyphthalimide products in moderate to good yields has been described. This methodology is distinguished by catalyst-free conditions, readily available starting materials, wide substrate scope and operational simplicity. In addition, a gram-scale reaction and synthetic transformation of the product into synthetically useful intermediates has been demonstrated.
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An operationally simple and convenient synthesis method toward a series of diverse spiro[4.4]thiadiazole derivatives via double [3 + 2] 1,3-dipolar cycloaddition of nitrilimines generated in situ from hydrazonyl chlorides with carbon disulfide has been achieved under mild reaction conditions.
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To improve the permeability and antifouling properties of polyvinyl chloride (PVC) ultrafiltration (UF) membrane, amphiphilic sulfonated polysulfone (SPSF) was introduced into PVC matrix. Three types of PVC/SPSF blend membranes containing different SPSF with the sulfonation degree (SD) of 20%, 30%, and 50% were fabricated by non-solvent induced phase separation (NIPS) process. The excellent compatibility between PVC and SPSF was confirmed by differential scanning calorimetry (DSC). Surface chemical compositions, morphology, roughness, charge, hydrophilicity, permeability and antifouling properties of the pristine PVC membrane and the PVC/SPSF blend membranes were systematically compared and characterized. Due to the improved hydrophilicity and endowed negative charge, the blend membrane showed high water permeability (i.e. 880 L m-2h-1 bar-1), high bovine serum albumin (BSA) rejection (i.e. 95.7%), and high flux recovery ratio (i.e. 96%), which outperformed ever reported and commercialized PVC membranes. Furthermore, the permeability and rejection properties of PVC/SPSF UF membranes were maintained after soaking in acidic and alkaline solutions for 30 days, indicating their outstanding acid and alkali tolerance. Therefore, SPSF was expected as a potential versatile modifier for fabricating high performance UF membranes.
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A simple and green procedure was established by [3 + 3] cycloaddition reaction of isatin derived cyclic imine 1,3-dipoles with α,ß-unsaturated aldehydes, giving the desired spiro heterocyclic oxindoles with aza-quaternary centers in good yields and diastereoselectivities. It should be noted that water can be employed as a suitable solvent for the improvement of diastereoselectivity.
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A highly diastereoselective dearomative [3 + 2] 1,3-dipolar cycloaddition reaction of nitrobenzothiophenes with an in situ-generated nonstabilized azomethine ylides has been developed. The transformation provides a series of functionalized fused tricyclic benzo[4,5]thieno[2,3-c]pyrroles in good yields (up to 92%) under mild reaction conditions. In addition, a gram-scale experiment and the synthetic transformation of the cycloadduct further highlighted the synthetic utility. The relative configurations of the typical products were clearly confirmed by X-ray crystallography.
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A novel tetrabutylammonium iodide (TBAI)-promoted three-component reaction of carboxylic acid with alkene and alcohol has been developed, which represents facile and straightforward access to polysubstituted γ-lactone skeletons in moderate-to-good yields. This methodology is distinguished by the use of a commercial catalyst and readily available starting materials, wide substrate scope, and operational simplicity. Mechanistic studies suggested that this transformation went through a radical process.
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A cross 1,3-dipolar cycloaddition of two different ylides between C,N-cyclic azomethine imines with an in situ-generated nonstabilized azomethine ylide from an N-benzyl precursor was realized. The reactions afforded a clean and facile access to diverse fused tricyclic 1,2,4-hexahydrotriazines in high yields (up to 96%). The chemical structures of the typical compounds were confirmed by X-ray single-crystal structure analysis.