Visible-Light-Induced, Graphene Oxide-Promoted C3-Chalcogenylation of Indoles Strategy under Transition-Metal-Free Conditions.

An efficient and general method for the synthesis of 3-sulfenylindoles and 3-selenylindoles employing visible-light irradiation with graphene oxide as a promoter at room temperature has been achieved. The reaction features are high yields, simple operation, metal-free and iodine-free conditions, an easy-to-handle oxidant, and gram-scalable synthesis. This simple protocol allows one to access a wide range of 3-arylthioindoles, 3-arylselenylindoles, and even 3-thiocyanatoindoles with good to excellent yields.

Photoinitiated Multicomponent Anti-Markovnikov Alkoxylation over Graphene Oxide.

The development of graphene oxide-based heterogeneous materials with an economical and environmentally-friendly manner has the potential to facilitate many important organic transformations but proves to have few relevant reported reactions. Herein, we explore the synergistic role of catalytic systems driven by graphene oxide and visible light that form nucleophilic alkoxyl radical intermediates, which enable an anti-Markovnikov addition exclusively to the terminal alkenes, and then the produced benzyl radicals are subsequently added with N-methylquinoxalones. This photoinduced cascade radical difunctionalization of olefins offers a concise and applicable protocol for constructing alkoxyl-substituted N-methylquinoxalones.

Consistency and applicability of different brief screen instrument of cognitive function in elderly population.

BACKGROUND: Screening for cognitive impairment (CI) is often hampered by lack of consensus as to which screening instrument to use. The aim is to assess the consistence and applicability of different CI screening tools. METHOD: In a cross-sectional study from October 2017 to September 2018 in 7 communities in Shanghai, China, elder (≧60) residential volunteers with no history of major cardiovascular diseases, cancers and other comorbidities known to affect cognitive functions were recruited. The participants underwent tests with 7 cognitive function screening instruments. Multivariate linear regressions were performed to test correlations between demographic characteristics, including gender, age, education, and marital status, with cognitive test scores. Mini-Mental State Examination (MMSE) score adjusted according to the correlation coefficients was used to detect CI with a cutoff of 24. Other cognitive function scores were compared between participants with and without CI. In addition, Pearson's correlation test was used to detect association between different test scores. RESULTS: 172 participants with relatively low education levels were included. Age and education showed significant association with cognitive test scores. Using adjusted MMSE, 39.6% of participants were identified with CI, while the percentage was 87.2% when adjusted Montreal Cognitive Assessment (MoCA) with cutoff of 26 was used. Analysis of "abnormal" test scores showed that MMSE had the highest percentage of valid data (98.8%). MoCA and Isaacs test of Verbal Fluency (VF) score had correlation with most the other scores, while MMSE only significantly associated with VF and MoCA. CONCLUSIONS: MMSE may still present the most applicable tools for quick screen of cognitive functions, especially when environmental conditions may interfere with participants' attention.

CoCl2-promoted TEMPO oxidative homocoupling of indoles: access to tryptanthrin derivatives.

A novel TEMPO/CoCl2-promoted aerobic oxidation of indoles was developed. The reaction provided one-step access to tryptanthrin derivatives in moderate to good yields and excellent regioselectivity via a cascade process. The reactions could be carried out under mild reaction conditions with varying functional group tolerance, especially halogen functional groups. Mechanistic studies disclosed that the oxygen atom in the desired product originated from molecular dioxygen.

Tuning the activity of the inert MoS2 surface via graphene oxide support doping towards chemical functionalization and hydrogen evolution: a density functional study.

The basal plane of MoS2 provides a promising platform for chemical functionalization and the hydrogen evolution reaction (HER); however, its practical utilization remains challenging due to the lack of active sites and its low conductivity. Herein, using first principles simulations, we first proposed a novel and effective strategy for significantly enhancing the activity of the inert MoS2 surface using a graphene oxide (GO) support (MoS2/GOs). The chemical bonding of the functional groups (CH3 and NH2) on the MoS2-GO hybrid is stronger than that in freestanding MoS2 or MoS2-graphene. Upon increasing the oxygen group concentration or introducing N heteroatoms into the GO support, the stability of the chemically functionalized MoS2 is improved. Furthermore, use of GOs to support pristine and defective MoS2 with a S vacancy (S-MoS2) can greatly promote the HER activity of the basal plane. The catalytic activity of S-MoS2 is further enhanced by doping N into GOs; this results in a hydrogen adsorption free energy of almost zero (ΔGH = ∼-0.014 eV). The coupling interaction with the GO substrate reduces the p-type Schottky barrier heights (SBH) of S-MoS2 and modifies its electronic properties, which facilitate charge transfer between them. Our calculated results are consistent with the experimental observations. Thus, the present results open new avenues for the chemical functionalization of MoS2-based nanosheets and HER catalysts.

Oxygen-Molecule Adsorption and Dissociation on BCN Graphene: A First-Principles Study.

Boron and nitrogen co-doped (BCN) graphene is an attractive material for use as a metal-free oxygen reduction reaction electrocatalyst and as other catalysts due to its unique structure and electronic properties. Reported here is the structure, determined by using density functional theory, of the active O2 -dissociation site of BCN graphene containing different types of BN cluster. The results show that the edge termination and shape of substitutional BN clusters are two important factors that determine the catalytic activity of BCN graphene for the dissociation of molecular oxygen. N-Terminated triangular BN (t-BN) cluster doping can reduce the energy barrier more effectively compared to a t-BN with a B edge or quadrangular BN cluster. Interestingly, the B atom neighboring the N edge, only in the case of N-terminated t-BN doping, is determined to be the most active site for O2 dissociation due to the barrier being as low as 0.08 eV. The electronic structure calculations reveal that in addition to the large positive charge densities, the catalytic activity of graphene enhanced by B,N doping is also attributed to the increased density of states of the π* states of the active site around the Fermi level.

A multifunctionalized strategy of indoles to C2-quaternary indolin-3-ones via a TEMPO/Pd-catalyzed cascade process.

A method for combinative oxidative homo dimerization and cyanomethylation of free indole derivatives catalysed by TEMPO and Pd(OAc)2 was demonstrated for the first time. This new methodology is both atom and step efficient and is applicable to a broad scope of substrates, allowing the synthesis of a range of synthetically valuable 2-(2-(1H-indol-3-yl)-3-oxoindolin-2-yl)acetonitriles in moderate to excellent yields.

Regioselective synthesis of 2,3'-biindoles mediated by an NBS-induced homo-coupling of indoles.

Mild conditions have been developed to achieve NBS-induced homodimerization of indole derivatives with excellent regioselectivity at 15 °C in high efficiency. This method provides a simple route to a 2,3'-linked biindolyl scaffold from the electron-rich to moderately electron-poor indoles. In addition, [3,2-a]carbazole derivatives can also be prepared through this method.

Diels-Alder reactions of graphene oxides: greatly enhanced chemical reactivity by oxygen-containing groups.

Graphene oxides (GOs) or reduced GOs (rGOs) may offer extraordinary potential for chemical functionalization of graphene due to their unique electronic and structural properties. By means of dispersion-corrected density functional theory computations, we systematically investigated the Diels-Alder (DA) chemistry of GOs. Our computations showed that the dual nature of GOs as both a diene and a dienophile is stronger than that of pristine graphene. Interestingly, the interior bonds of a graphene surface modified by oxygen-containing groups could be functionalized by maleic anhydride (MA) and 2,3-dimethoxybutadiene (DMBD) through cycloaddition reactions, and the cycloaddition products of MA and DMBD are more favorable than the non-covalent complexes between these reagents and the GO surface. The feasibility of covalent functionalization of GOs as a diene and a dienophile strongly depends on the local structural environment of the oxygen groups, including the atomic arrangement and the number of these groups surrounding the reaction site. The exothermicities for (4+2) adducts of DMBD with GO are far larger than those of MA, which indicates that the dienophile character of the GO surface is stronger than its behavior as a diene.

Anion Effects on Lanthanide(III) Tetrazole-1-acetate Dinuclear Complexes Showing Slow Magnetic Relaxation and Photofluorescent Emission.

Three types of lanthanide complexes based on the tetrazole-1-acetic acid ligand and the 2,2'-bipyridine coligand were prepared and characterized by single-crystal X-ray diffraction, IR spectroscopy, and elemental analyses; the formulas of these complexes are [Ln2(1-tza)4(NO3)2(2,2'-bipy)2] (Ln = Sm (1), Eu (2), Gd (3), Tb (4), Dy (5)), [Dy2(1-tza)4Cl2(2,2'-bipy)2] (6), and [Yb2(1-tza)4(NO3)2(2,2'-bipy)2] (7) (1-tza = tetrazole-1-acetate and 2,2'-bipy = 2,2'-bipyridine). They are dinuclear complexes possessing similar structures but different lanthanide(III) ion coordination geometries because of the distinction of peripheral anions (such as NO3(-) and Cl(-)) and the effect of lanthanide contraction. The variable-temperature magnetic susceptibilities of 1-6 were measured. Both Dy(III) complexes (5 and 6) display field-induced single-molecule magnet behaviors. Ab initio calculations revealed that the Dy(III) complex 6 possesses a more anisotropic Dy(III) ion in comparison to that in 5. The room-temperature photoluminescence spectra of Sm(III) (1), Eu(III) (2), Tb(III) (4), and Dy(III) (5 and 6) complexes exhibit strong characteristic emissions in the visible region, whereas the Yb(III) (7) complex shows near-infrared (NIR) luminescence.

NiSO4-catalyzed C-H activation/C-S cross-coupling of 1,2,3-triazole N-oxides with thiols.

An efficient nickel-catalyzed protocol for C-S cross-coupling through the direct functionalization of 2-aryl-1,2,3-triazole N-oxide C-H bonds with aryl or alkyl thiols, or diphenyl disulfide has been developed. The targeted N(+)-O(-) bond cleavage can be observed during the reaction, and thus obviates the need to use an additional deoxygenation step. This new protocol for the preparation of thiolated 2-aryl-1,2,3-triazoles appears to offer good yields with high regioselectivity, mild conditions, and a wide substrate scope.

Metal-free (Boc)2O-mediated C4-selective direct indolation of pyridines using TEMPO.

Direct metal-free C-4-selective indolation of pyridines is achieved for the first time using TEMPO and (Boc)2O. A variety of substituents on both indoles and pyridines are tolerated to give 3-(pyridin-4-yl)-1H-indole derivatives in moderate to excellent yields. This finding provides a novel approach for developing metal-free C-H functionalization of pyridines.

Highly efficient synthesis of 2,5-disubstituted pyrazines from (Z)-ß-haloenol acetates.

A highly efficient synthesis of a wide range of 2,5-disubstituted pyrazines from (Z)-ß-haloenol acetates is described. The reactions are conducted under convenient conditions and provide products with excellent regioselectivity in moderate to excellent yields with a broad substrate scope, including a variety of aromatic and aliphatic haloenol acetates.

Cu(II)-catalyzed highly regio- and stereoselective construction of C-C double bonds: an efficient method for the ketonization-olefination of indoles.

A general and efficient method for the cross-coupling of indoles with ß-keto esters by using TEMPO/CuSO4·5H2O in air as oxidant has been developed. This reaction features high functional-group compatibility and an excellent selectivity. This methodology provides an alternative approach for the ketonization-olefination of indoles in moderate to good yields.

Tunable doping and band gap of graphene on functionalized hexagonal boron nitride with hydrogen and fluorine.

First-principles calculations have been used to investigate the structural and electronic properties of graphene supported on functionalized hexagonal boron nitride (h-BN) with hydrogen and fluorine atoms. Our results show that the hydrogenation and fluorination of the h-BN substrate modify the electronic properties of graphene. Interactions of graphene with fully hydrogenated or fully fluorinated h-BN and half-hydrogenated and half-fluorinated h-BN with H at N sites and F at the B sites can lead to n- or p-type doping of graphene. The different doping effect may be attributed to the significant charge transfer from graphene to the substrate. Interestingly, when graphene is supported on the functionalized h-BN with H at B sites and F at N sites (G/HBNF), a finite band gap of 79 meV in graphene is opened due to the equivalence breaking of two sublattices of graphene, and can be effectively modulated by changing the interlayer spacing, increasing the number of functionalized BN layers, and applying an external electric field. More importantly, the modification of the band gap in G/HBNF with a functionalized BN bilayer by the electric field is more pronounced than that of the single-layer h-BN, which is increased to 408 meV with 0.8 V Å(-1). Thus, graphene on chemically modified h-BN with a tunable and sizeable band gap may provide a novel way for fabricating high-performance graphene-based nanodevices.

Metal-free catalyzed oxidative trimerization of indoles by using TEMPO in air: a biomimetic approach to 2-(1H-indol-3-yl)-2,3'-biindolin-3-ones.

A simple, convenient and efficient metal-free catalyzed oxidative trimeric reaction of indoles toward a variety of 2-(1H-indol-3-yl)-2,3'-biindolin-3-one derivatives in moderate to excellent yields has been developed. This transformation proceeds via a tandem oxidative homocoupling reaction by using TEMPO in air as an environmentally benign oxidant. This methodology provides an alternative approach for the direct generation of all-carbon quaternary centers at the C3 position of indoles.

RuCl3·3H2O catalyzed reactions: facile synthesis of bis(indolyl)methanes under mild conditions.

RuCl3·3H2O was found to be an effective catalyst for reactions of indoles, 2-methylthiophene, and 2-methylfuran with aldehydes to afford the corresponding bis(indolyl)methanes, bis(thienyl)methanes, and bis(fur-2-yl)methanes in moderate to excellent yields. Experimental results indicated that mono(indolyl)methanol is not the reaction intermediate under these reaction conditions.

Graphene oxide-catalyzed trifluoromethylation of alkynes with quinoxalinones and Langlois' reagent.

The direct C-H trifluoromethylation of alkynes and quinoxalinones has been achieved using a graphene oxide/Langlois' reagent system. This multi-component tandem reaction using graphene oxide as the catalyst and Langlois' reagent as the robust CF3 radical source results in the formation of olefinic C-CF3 to access a series of 3-trifluoroalkylated quinoxalin-2(1H)-ones.

A general and simple diastereoselective reduction by L-Selectride: efficient synthesis of protected (4S,5S)-dihydroxy amides.

A general approach to (4S,5S)-4-benzyloxy-5-hydroxy-N-(4-methoxybenzyl) amides 10 based on a diastereoselective reduction of (5S,6RS)-6-alkyl-5-benzyloxy-6-hydroxy-2-piperidinones 6 and their tautomeric ring-opened keto amides 7 is described. The reduction with L-Selectride at -20 degrees C to room temperature afforded the products 10 in excellent yields and moderate to high syn-diastereoselectivities.

ATAS Acupuncture Reduces Chemotherapy Induced Fatigue in Breast Cancer Through Regulating ADROA1 Expression: A Randomized Sham-Controlled Pilot Trial.

OBJECTIVE: To investigate the feasibility and effectiveness of ATAS acupuncture (Acupoints-Time-Space Acupuncture) as a non-pharmacological intervention to prevent or relieve chemotherapy-induced fatigue in breast cancer patients undergoing taxane chemotherapy. METHODS: A pilot study in Kunming center with the aim of evaluating 40 patients randomized to 3 groups: ATAS, sham and non-acupuncture with an unequal randomization of 2:1:1. Participants with stage I-III breast cancer were scheduled to receive adjuvant EC4P4 chemotherapy. Participants in the ATAS and sham acupuncture arms received 20 sessions of acupuncture over 20 weeks, non-acupuncture arm received usual care. Evaluation scales, including VAS-F, MFI-20, HDAS, ISI, and blood samples were collected at four timepoints (T1-T4). mRNA sequencing was performed to detect the mechanism of acupuncture. RESULTS: A total of 581 sessions of acupuncture were performed on patients in the acupuncture group. There was no difference between the three groups in terms of clinical characteristics. Patients randomized to ATAS acupuncture had improved symptoms including fatigue, anxiety and insomnia during the whole process of chemotherapy compared with the other two groups. The VAS-F score of ATAS acupuncture group was decreased compared with non-acupuncture group (P=0.004). The score of MFI-20 in ATAS acupuncture group was kept at low level, while the other two groups' scores kept climbing during chemotherapy (P=0.016; P=0.028, respectively). The mechanism of ATAS acupuncture which reduced fatigue and depression may be related to ADROA1, by regulating cGMP/PKG pathway. CONCLUSION: This pilot study has demonstrated that ATAS acupuncture can significantly reduce fatigue induced by chemotherapy. TRIAL REGISTRATION: Chinese Clinical Trials Registry, ChiCTR-IPR-17,013,652, registered Dec 3, 2017. http://www.chictr.org.cn/. PROTOCOL VERSION: Version 3.2 dated from 2018/04/20.