Titanium-catalyzed highly stereoselective anti-Markovnikov intermolecular hydroalkoxylation of alkynes to prepare Z-enol ethers.

Enol ethers are essential synthetic frameworks and widely applied in organic synthesis; however, high regio- and stereo-selective access to enol ethers remains challenging. Herein, we report a titanium-catalyzed stereospecific anti-Markovnikov hydroalkoxylation reaction of alkynes for the synthesis of Z-enol ethers with excellent functional group tolerance and yields. Mechanistic studies showed that the titanium coordinates with the alkyne and then an oxygen anion attacks the π-bond of the alkyne from the backside to provide a trans-oxygen metallation intermediate, which accounts for the high Z-stereoselectivity. Furthermore, Z-enol ethers could be applied as a kind of synthon for late-stage transformations and gram-scale synthesis, which demonstrates their potential value in organic synthesis.

A Conjugated Microporous Polymer/Wood Aerogel with Physical Adsorption, Chemical Degradation and Antibacterial Self-Cleaning Triple Sewage Treatment Functions.

Conjugated microporous polymers (CMPs) have important applications in the fields of optoelectronics and sewage treatment due to their high specific surface area, broad visible absorption, processability and simple synthesis process. Biocompatibility, recycling, mass production and solar photodegradation are particularly important in wastewater treatment. Here, A CMP with a high specific surface area and a hierarchical pore structure (CPOP) was constructed based on 4,4',4″-Tris(carbazol-9-yl)-triphenylamine (3CZ-TPA). Furthermore, a CMP-loaded wood aerogel (CPOP/wood aerogel) with physical adsorption, chemical degradation, bacterial inhibition and self-cleaning properties was prepared by in situ polymerization and used for wastewater treatment. The obtained CPOP/wood aerogel is highly biocompatible and easy to recycle. In addition, the inherent broad visible light absorption property of CPOP endows it with promising photocatalytic properties. Subsequently, we investigated the photocatalytic mechanism of CPOP, and the results showed that it was mainly affected by peroxyl radicals, which implied and confirmed its microbial self-cleaning for secondary cleaning of water pollutants. The reported studies on CPOP/wood aerogel provide a new direction for water purification materials with excellent adsorption, degradation and antibacterial properties.

CuI-catalyzed synthesis of multisubstituted pyrido[1,2-a]pyrimidin-4-ones through tandem Ullmann-type C-N cross-coupling and intramolecular amidation reaction.

Various multi-substituted pyrido[1,2-a]pyrimidin-4-ones were synthesized via a one-pot tandem CuI-catalyzed C-N bond formation/intramolecular amidation reaction at 130 °C in DMF. This protocol features simple operation, broad substrate scope, good functional group tolerance and gram scale preparation, thus allowing practical and modular synthesis of pyrido[1,2-a]pyrimidin-4-ones from readily available 2-halopyridine and (Z)-3-amino-3-arylacrylate ester in good to excellent yields.

Novel lignin-supported copper complex as a highly efficient and recyclable nanocatalyst for Ullmann reaction.

In this work, we prepared polyhydroxylated lignin by demethylation and hydroxylation of lignin, and grafted phosphorus-containing groups by nucleophilic substitution reaction, the resulting material could be used as a carrier for the preparation of heterogeneous Cu-based catalysts (PHL-CuI-OPR2). The optimal PHL-CuI-OPtBu2 catalyst was characterized by FT-IR, TGA, BET, XRD, SEM-EDS, ICP-OES, XPS. The catalytic performance of PHL-CuI-OPtBu2 in the Ullmann CN coupling reaction was evaluated using iodobenzene and nitroindole as model substrates under nitrogen atmosphere with DME and H2O as cosolvent at 95 °C for 24 h. The applicability of modified lignin-supported copper catalyst was investigated of various aryl/heteroaryl halides with indoles under optimal conditions, the corresponding products were obtained with high yield. Additionally, it could be easily recovered from the reaction medium by an easy centrifugation and washing.

Acidity Scale in a Choline Chloride- and Ethylene Glycol-Based Deep Eutectic Solvent and Its Implication on Carbon Dioxide Absorption.

An equilibrium acidity (pKa) scale that comprises 16 Brönsted organic acids, including phenols, carboxylic acids, azoles, and phenylmalononitriles, was established in a choline chloride/EG-based deep eutectic solvent (DES) ([Ch][Cl]:2EG) by ultraviolet-visible (UV-Vis) spectroscopic methods. The established acidity scale spans about 6 pK units in the DES, which is similar to that for these acids in water. The acidity comparisons and linear correlations between the DES and other solvents show that the solvent property of [Ch][Cl]:2EG is quite different from those of amphiphilic protic and dipolar aprotic molecular solvents. The carbon dioxide absorption capabilities as well as apparent absorption kinetics for a series of anion-functionalized DESs ([Ch][X]:2EG) were measured, and the results show that the basicity of comprising anion [X] of choline salt is essential for the maximum carbon dioxide absorption capacity, i.e., a stronger basicity leads to a greater absorption capacity. The possible absorption mechanisms for carbon dioxide absorption in these DESs were also discussed based on the spectroscopic evidence.

Polyoxometalate-covalent organic framework hybrid materials for pH-responsive photothermal tumor therapy.

Photothermal therapy (PTT) has become one of the most effective methods for tumor treatment. With the development of medicine, studies focusing primarily on therapeutic and diagnostic agents with desirable biocompatibility, targeting and stability are still of great significance. Heteropoly blue (HPB) is an ideal photothermal therapy agent (PTA) with decent photothermal conversion efficiency. Covalent organic frameworks (COFs) are considered to be good carriers with excellent biocompatibility. Due to their superior characteristics, such as being adjustable, and having high thermal stability and porous structures, COFs have been broadly applied in various fields. In this study, HPB was successfully in situ loaded into a COF via a one-pot method. The resultant HPB@COF platform exhibited desirable biocompatibility, pH-responsive release properties and high tumor inhibition efficiency, which can be used for PTT to effectively inhibit tumor growth. Our work provides a valuable paradigm for the fabrication of safer and effective HPB@COF NPs for future pH-responsive photothermal therapy.

Palladium-Catalyzed Synthesis of Fluorescent Benzo[4,5]imidazo[1,2-a]pyridines through Annulation Reaction of Benzimidazoles and Alkynyl Bromides with Internal Alkynes.

An efficient synthesis of fused azapolycycles based on (benz)imidazole and pyridine scaffolds has been developed. In all cases, the first nucleophilic addition of (benz)imidazoles to alkynyl bromides in tert-pentyl alcohol can proceed in a stereoselective manner to provide (Z)-N-(1-bromo-1-alken-2-yl)benzimidazoles at 110 °C. Sequentially, these adducts containing alkenyl bromide can undergo Pd-catalyzed intermolecular C-H annulation in the presence of internal alkynes in dimethylacetamide, affording fluorescent (benz)imidazole-fused pyridines in good to high yields. These compounds generally exhibit blue or green fluorescences (454-503 nm for solution states and 472-506 nm for solid states), and the fluorescence quantum yields remained in 0.19-0.89 and 0.02-0.74 for solution and solid states, respectively.

Transition-Metal-Free One-Pot Synthesis of Naphthoquinonefuran Derivatives Through Sequential Nucleophilic Substitution-Nucleophilic Addition Reaction.

A transition-metal-free route for tandem one-pot synthesis of naphthoquinonefuran derivatives from 2-hydroxynaphthoquinones has been developed. The sequentially accomplished process comprises an intermolecular alkynylation of sp2-carbon at the 3 position of 2-hydroxynaphthoquinones with arylethynyl bromides, followed by a base-promoted intramolecular nucleophilic annulation reaction. A broad range of functional groups is compatible with this reaction, and diverse naphtho[2,3-b]furan-4,9-diones can be obtained with good yields and excellent regioselectivity.

Palladium(II)-Catalyzed Oxidative Annulation of 2-Hydroxynaphthalene-1,4-diones and Internal Alkynes via C-H Functionalization.

An efficient Pd(II)-catalyzed oxidative annulation of 2-hydroxynaphthalene-1,4-diones and internal alkynes has been developed with high step efficiency. A broad range of functional groups are compatible with this reaction, thus providing a new entry to diverse naphtho[2,3-b]furan-4,9-dione derivatives in good to high yields.

Copper(ii)-catalyzed synthesis of multisubstituted indoles through sequential Chan-Lam and cross-dehydrogenative coupling reactions.

Starting from arylboronic acids and ester (Z)-3-aminoacrylates, one-pot syntheses of diverse indole-3-carboxylic esters have been described through copper(ii)-catalyzed sequential Chan-Lam N-arylation and cross-dehydrogenative coupling (CDC) reactions. The initial Chan-Lam arylation can proceed in DMF at 100 °C for 24 h to give ester (Z)-3-(arylamino)acrylate intermediates in the presence of Cu(OAc)2/tri-tert-butylphosphine tetrafluoroborate, a catalytic amount of myristic acid as the additive, KMnO4 and KHCO3. Sequentially, these in situ arylated intermediates can undergo an intramolecular oxidative cross-dehydrogenative coupling process in mixed solvents (DMF/DMSO = 2 : 1) at 130 °C to give C3-functionalized multi-substituted indole derivatives.

Palladium-catalyzed tandem one-pot synthesis of π-expanded imidazoles through a sequential Heck and oxidative amination reaction.

An efficient palladium-catalyzed route for tandem synthesis of imidazole-fused polyheterocycles from 2-vinyl imidazoles and aryl halides is described. The sequentially accomplished process comprises intermolecular Heck arylation of 2-vinyl imidazoles followed by an intramolecular aerobic oxidative C-H amination reaction promoted by the same Pd catalyst. This Pd-catalyzed tandem approach offers a straightforward protocol for the assembly of benzimidazo/phenanthroimidazo[1,2-a]quinolines in moderate to high yields, serving as a useful tool for the discovery of fluorescent materials.

Tunable synthesis of quinolinone-fused isoquinolines through sequential one-pot nucleophilic addition and palladium-catalyzed intramolecular C-H alkenylation.

An efficient sequential one-pot synthesis of fused heterocycles based on 4-quinolinone and isoquinoline scaffolds of biological interest has been developed. In all cases, the first nucleophilic addition of 2-aryl quinolin-4(1H)-ones to alkynyl bromides in tert-pentyl alcohol can proceed in a chemo-, regio- and stereoselective manner to give (Z)-N-(1-bromo-1-alken-2-yl)quinolin-4-ones at 110 °C. Sequentially, these in situ functionalized adducts can undergo direct intramolecular aromatic C-H alkenylation in the presence of PdCl2 (5 mol%) in mixed solvents (tert-pentyl alcohol/DMF = 1 : 1), affording the novel quinolinone-fused isoquinoline derivatives in good yields.

Copper-Catalyzed Synthesis of Multisubstituted Indoles through Tandem Ullmann-Type C-N Formation and Cross-dehydrogenative Coupling Reactions.

Multisubstituted indoles were synthesized via a one-pot tandem copper-catalyzed Ullmann-type C-N bond formation/intramolecular cross-dehydrogenative coupling process at 130 °C in DMSO. The methodology allows practical and modular assembly of indoles in good to excellent yields from readily available aryl iodides and enamines.

Synthesis of 4H-Chromen-4-one Derivatives by Intramolecular Palladium-Catalyzed Acylation of Alkenyl Bromides with Aldehydes.

The palladium-catalyzed intramolecular acylation of alkenyl bromides and aldehydes was developed for an efficient synthesis of 4H-chromen-4-ones. With Pd(PPh3)4/Xphos as the catalyst and K2CO3 as the base, this protocol was applied to synthesize a small library of diversely functionalized flavonoids in moderate to good yields in 1,4-dioxane.

High rate of missed HIV infections in individuals with indeterminate or negative HIV western blots based on current HIV testing algorithm in China.

It remains unclear if China's current HIV antibody testing algorithm misses a substantial number of HIV infected individuals. Of 196 specimens with indeterminate or negative results on HIV western blot (WB) retrospectively examined by HIV-1 nucleic acid test (NAT), 67.57% (75/111) of indeterminate WB samples, and 16.47% (14/85) of negative WB samples were identified as NAT positive. HIV-1 loads in negative WB samples were significantly higher than those in indeterminate WB samples. Notably, 86.67% (13/15) of samples with negative WB and double positive immunoassay results were NAT positive. The rate of HIV-1 infections missed by China's current HIV testing algorithm is unacceptably high. Thus, China should consider using NAT or integrating fourth generation ELISA into current only antibodies-based HIV confirmation. J. Med. Virol. 88:1462-1466, 2016. © 2016 Wiley Periodicals, Inc.

Circulation of human metapneumovirus among children with influenza-like illness in Wuhan, China.

Human metapneumovirus (HMPV) is a worldwide distributed pathogen of the respiratory tract. The objectives of this study were to identify HMPV infections among children with influenza-like illness (ILI) in Wuhan and to assess circulation patterns and molecular diversity of HMPV in this area. From July 2008 to December 2013, a total of 3,883 throat swab samples were collected from ILI outpatients under 16 years old. HMPV RNA was detected in 171 samples (4.40%). All the four subtypes of HMPV were identified, among which A2 was the most common subtype (61/145, 42.1%), followed by B1, B2, and A1. During the study period, HMPV circulation presented a biennial alternation between high and low incidence in Wuhan and the seasonal peak also shift between winter and spring in two continuous seasons. Subtype A2, B1, and B2 co-circulated during the study period, with genotype A prevailing in epidemic season 2008-2009 and 2012-2013, and genotype B prevailing during other periods. This large-scale analysis of HMPV prevalence in ILI outpatient children improves the understanding of local HMPV circulation patterns and provides molecular epidemic evidence for comparative analysis of HMPV infection.

Short Communication: HIV-1 Infection Suppresses Circulating Viral Restriction microRNAs.

MicroRNAs (miRNAs) participate in host innate immunity against HIV-1 infection. We examined the impact of HIV-1 infection on viral restriction miRNAs in plasma of HIV-1-infected subjects. HIV-1-infected subjects had significantly lower plasma levels of HIV-1 restriction miRNAs (miRs-29a, -29b, -125b, -223, -198, and -382) than control subjects. Further in vitro studies showed that HIV-1 infection of macrophages suppressed production of the extracellular miRs-29b, -125b, and -223. These data demonstrate the compelling evidence that HIV-1 infection impairs host innate immunity by inhibiting antiviral miRNAs, which provide a possible mechanism for HIV-1 persistence in the host.

Antiretroviral Therapy Fails to Restore Levels of HIV-1 Restriction miRNAs in PBMCs of HIV-1-infected MSM.

A number of cellular microRNAs (miRNAs) have been identified to have the ability to inhibit HIV-1 replication. In this study, we examined the impact of combination antiretroviral therapy (cART) on the expression of HIV-1 restriction miRNAs in peripheral blood mononuclear cells of HIV-1-infected men who have sex with men (MSM). Compared with male healthy donors, HIV-infected MSM had significantly lower levels of 9 HIV-1 restriction miRNAs. The treatment of HIV-1-infected MSM with cART, however, failed to restore the levels of these miRNAs in peripheral blood mononuclear cells. These observations suggest that the suppression of the cellular restriction miRNAs by HIV-1 may attribute to the virus latency during cART.

Heroin inhibits HIV-restriction miRNAs and enhances HIV infection of macrophages.

Although opioids have been extensively studied for their impact on the immune system, limited information is available about the specific actions of opioids on intracellular antiviral innate immunity against HIV infection. Thus, we investigated whether heroin, one of the most abused drugs, inhibits the expression of intracellular HIV restriction microRNA (miRNA) and facilitates HIV replication in macrophages. Heroin treatment of macrophages enhanced HIV replication, which was associated with the downregulation of several HIV restriction miRNAs. These heroin-mediated actions on the miRNAs and HIV could be antagonized by naltrexone, an opioid receptor antagonist. Furthermore, the in vitro negative impact of heroin on HIV-associated miRNAs was confirmed by the in vivo observation that heroin addicts had significantly lower levels of macrophage-derived HIV restriction miRNAs than those in the control subjects. These in vitro and in vivo findings indicate that heroin use compromises intracellular anti-HIV innate immunity, providing a favorable microenvironment for HIV survival in the target cells.