Fluoroalkylation reactions in aqueous media: a review Song, Hai-Xia; Han, Qiu-Yan; Zhao, Cheng-Long ...
Green chemistry : an international journal and green chemistry resource : GC,
2018, Volume:
2, Issue:
8
Journal Article
Peer reviewed
This review highlights the progress of aqueous fluoroalkylation over the past few decades. Fluorine-containing functionalities are important design elements in new pharmaceuticals, agrochemicals, and ...functional materials, due to their unique effects on the physical, chemical, and/or biological properties of a molecule. Because the environmental concerns are receiving increasing attention in organic synthesis, the development of methods for the mild, environment-friendly, and efficient incorporation of fluorinated or fluoroalkylated groups into the target molecules is of broad interest. At the early stage, most of the fluoroalkylation reactions and their variants were thought in principle to be hydrophobic. Recently, the environment-benign fluoroalkylation reactions by taming nucleophilic, radical, or electrophilic fluoroalkylation reagents in water or in the presence of water have been explored, building a new prospect for green chemistry. The use of significant catalytic systems and/or the newly developed reagents is the key to the success of these reactions. Water is used as a (co)solvent and/or a reactant in aqueous fluoroalkylation, including trifluoromethylation, difluoromethylation, monofluoromethylation, trifluoroethylation, perfluoroalkylation, trifluoromethylthiolation, and other conversions, under environment-friendly conditions. Although great accomplishments have been achieved, they are just the tip of the iceberg with a wide scope for improvement. This review will draw great attention and inspire more contributions in the development of new aqueous fluoroalkylation reactions.
Recent advances in aqueous fluoroalkylation using various fluoroalkylation reagents are summarized in this review.
Synaptic pruning during adolescence is important for appropriate neurodevelopment and synaptic plasticity. Aberrant synaptic pruning may underlie a variety of brain disorders such as schizophrenia, ...autism and anxiety. Dopamine D2 receptor (Drd2) is associated with several neuropsychiatric diseases and is the target of some antipsychotic drugs. Here we generate self-reporting Drd2 heterozygous (SR-Drd2
) rats to simultaneously visualize Drd2-positive neurons and downregulate Drd2 expression. Time course studies on the developing anterior cingulate cortex (ACC) from control and SR-Drd2
rats reveal important roles of Drd2 in regulating synaptic pruning rather than synapse formation. Drd2 also regulates LTD, a form of synaptic plasticity which includes some similar cellular/biochemical processes as synaptic pruning. We further demonstrate that Drd2 regulates synaptic pruning via cell-autonomous mechanisms involving activation of mTOR signaling. Deficits of Drd2-mediated synaptic pruning in the ACC during adolescence lead to hyper-glutamatergic function and anxiety-like behaviors in adulthood. Taken together, our results demonstrate important roles of Drd2 in cortical synaptic pruning.
Optical characteristics of luminescent materials, including emission color (wavelength), lifetime, and excitation mode, play crucial roles in data communication and information security. Conventional ...luminescent materials generally display unicolor, unitemporal, and unimodal (occasionally bimodal) emission, resulting in low‐level readout and decoding. The development of multicolor, multitemporal, and multimodal luminescence in a single material has long been considered to be a significant challenge. In this study, for the first time, the superior integration of colorful (red–orange–yellow–green), bitemporal (fluorescent and delayed), and four‐modal (thermo‐/mechano‐motivated and upconverted/downshifted) emissions in a particular piezoelectric particle via optical multiplexing of dual‐lanthanide dopants is demonstrated. The as‐prepared versatile NaNbO3:Pr3+,Er3+ luminescent microparticles shown are particularly suitable for embedding into polymer films to achieve waterproof, flexible/wearable and highly stretchable features, and synchronously to provide multidimensional codes that can be visually read‐out using simple and commonly available tools (including the LED of a smartphone, pen writing, cooling–heating stimuli, and ultraviolet/near‐infrared lamps). These findings offer unique insight for designing highly integrated stimuli‐responsive luminophors and smart devices toward a wide variety of applications, particularly advanced anticounterfeiting technology.
Thermo‐mechano‐opto‐responsive bitemporal (fluorescent and delayed) colorful (red–orange–yellow–green) luminescence is designed and achieved through optical multiplexing of dual‐lanthanides of Pr3+ and Er3+ in NaNbO3 piezoelectric microparticles. The smart materials are well‐embedded into polymer elastomers to show waterproof, flexible/wearable and highly‐stretchable features, and provide multidimensional codes that enable visual readout using commonly available tools (e.g., smartphone flashlight, pen writing, and cooling‐heating stimuli).
Two-dimensional (2D) topological materials, including quantum spin/anomalous Hall insulators, have attracted intense research efforts owing to their promise for applications ranging from low-power ...electronics and high-performance thermoelectrics to fault-tolerant quantum computation. One key challenge is to fabricate topological materials with a large energy gap for room-temperature use. Stanene-the tin counterpart of graphene-is a promising material candidate distinguished by its tunable topological states and sizeable bandgap. Recent experiments have successfully fabricated stanene, but none of them have yet observed topological states. Here we demonstrate the growth of high-quality stanene on Cu(111) by low-temperature molecular beam epitaxy. Importantly, we discovered an unusually ultraflat stanene showing an in-plane s-p band inversion together with a spin-orbit-coupling-induced topological gap (~0.3 eV) at the Γ point, which represents a foremost group-IV ultraflat graphene-like material displaying topological features in experiment. The finding of ultraflat stanene opens opportunities for exploring two-dimensional topological physics and device applications.
Biological entities are involved in intricate and complex interactions, in which uncovering the biological information from the network concepts are of great significance. Benefiting from the ...advances of network science and high-throughput biomedical technologies, studying the biological systems from network biology has attracted much attention in recent years, and networks have long been central to our understanding of biological systems, in the form of linkage maps among genotypes, phenotypes, and the corresponding environmental factors. In this review, we summarize the recent developments of computational network biology, first introducing various types of biological networks and network structural properties. We then review the network-based approaches, ranging from some network metrics to the complicated machine-learning methods, and emphasize how to use these algorithms to gain new biological insights. Furthermore, we highlight the application in neuroscience, human disease, and drug developments from the perspectives of network science, and we discuss some major challenges and future directions. We hope that this review will draw increasing interdisciplinary attention from physicists, computer scientists, and biologists.
Probiotics are considered to be a potential treatment for ulcerative colitis (UC). The aim of this study was to compare the preventive effect of a space flight‐induced mutant L. reuteri F‐9‐35 and ...its wild type on UC in vivo. Female mice were randomly assigned to five groups: one normal and four colitic. Mice from colitis groups were daily gavaged with 0.2 mL 12% (w/v) skim milk containing the mutant or wild type (1 × 1011 CFU/mL), skim milk alone or distilled water for the whole experiment period, starting 7 days before colitis induction. UC was induced by administrating mice with 3.5% (w/v) dextran sulfate sodium (DSS) in drinking water for 7 days, after which DSS was removed and maintained for 3 days as a recovery phase. The results showed that the mice fed with L. reuteri F‐9‐35 had less inflammatory phenotype according to macroscopic and histological analysis, reduced myeloperoxidase activity, and lower expression of proinflammatory genes (Tumor necrosis factor‐α, cyclooxygenase‐2 and interleukin‐6) in colonic tissue compared with control. Furthermore, L. reuteri F‐9‐35 protected the mice from gut microbiota dysbiosis from DDS induced colitis. Neither wild type nor the milk alone had such beneficial effects. From above we conclude that L. reuteri F‐9‐35 has great potential in the prevention of UC as a dietary supplement.
Practical Application
Ulcerative colitis (UC) is the most common inflammatory bowel diseases and there is still a lack of safe and effective treatments. Consumption of L. reuteri F‐9‐35 may effective in preventing human UC.
Mountainous peatlands are one of the most important terrestrial ecosystems for carbon storage and play an important role in the global carbon cycle. An insight into the carbon cycle of peat swamps ...located in mountainous regions can be obtained by studying the distribution of soil organic carbon (SOC) and its relationships with environmental factors. This study focused on the development conditions of peat swamps in the Gahai wetlands, located on the Zoigê Plateau, China, with four different altitudinal gradients as experimental sample sites. The distribution of SOC and its relationship with environmental factors were analysed through vegetation surveys and a generalized additive model (GAM). The results show that with increasing altitude, soil temperature decreased while the soil pH and bulk density initially decreased then increased. On the contrary, the topographic wetness index (TWI), SOC content, above‐ground biomass and litter count initially increased then decreased. The SOC content of the 0–30 cm soil layer was in the range 226–330 g·kg−1 (coefficient of variation (CV) = 21.4%), and the 30–60 cm layer was 178–257 g·kg−1 (CV = 17.5%) and was significantly correlated (p < .05) with above‐ground biomass and litter count. Meanwhile, the SOC content in the 60–90 cm soil layer was in the range 132–167 g·kg−1 (CV = 9.2%) with a significant correlation (p < .05) with soil temperature, pH, bulk density and topographic moisture index. The study showed that the SOC content exhibited more pronounced spatial patterns with increasing altitude, with the peak value in the shallow soil layer appearing in lower elevation areas compared with the deep soil layer. The level of variation changed from medium to low, reflecting the stable mechanism for maintaining SOC within the heterogeneous peat swamp environment.
Carbon and nitrogen are the two most abundant nutrient elements for all living organisms, and their metabolism is tightly coupled. What are the signaling mechanisms that cells use to sense and ...control the carbon/nitrogen (C/N) metabolic balance following environmental changes? Based on studies in cyanobacteria, it was found that 2-phosphoglycolate derived from the oxygenase activity of Rubisco (ribulose-1,5-bisphosphate carboxylase/oxygenase) and 2-oxoglutarate from the Krebs cycle act as the carbon- and nitrogen-starvation signals, respectively, and their concentration ratio likely reflects the status of the C/N metabolic balance. We will present and discuss the regulatory principles underlying the signaling mechanisms, which are likely to be conserved in other photosynthetic organisms. These concepts may also contribute to developments in the field of biofuel engineering or improvements in crop productivity.
Cyanobacteria are simple models among photosynthetic organisms for studying the metabolic regulation of carbon/nitrogen (C/N), the two most abundant nutrient elements for all living organisms.
2-Oxoglutarate (2-OG), an intermediate from the Krebs cycle, serves as a carbon skeleton for nitrogen assimilation and as a signal of nitrogen limitation, whereas 2-phosphoglycolate (2-PG), an intermediate from photorespiration, acts as a signal of inorganic carbon limitation.
The levels of 2-PG and 2-OG are inversely correlated, and their ratio reflects the C/N metabolic balance.
The transcriptional activator NtcA is a sensor of 2-OG, and the transcriptional repressor NdhR is a sensor of both 2-OG and 2-PG. These regulators together balance C/N metabolic networks by switching on or off the expression of genes involved mainly in the uptake and assimilation of carbon and nitrogen sources.
The signaling role of 2-OG and 2-PG in C/N balance is likely conserved in other photosynthetic organisms.
Herein, we report the development of a method for highly regio‐, stereo‐, and enantioselective B−H bond insertion reactions of α‐silylcarbenes generated from 1‐silylcyclopropenes in the presence of a ...chiral copper(I)/bisoxazoline catalyst for the construction of chiral γ,γ‐disubstituted allylic gem‐silylboranes, which cannot be prepared by any other known methods. This reaction is the first highly enantioselective carbene insertion reaction of α‐silylcarbenes ever to be reported. The method shows general applicability for various 3,3‐disubstituted silylcyclopropenes and exclusively affords E‐products. The novel chiral γ,γ‐disubstituted allylic gem‐silylborane products are versatile allylic bimetallic reagents with high stability and have great synthetic potential, especially for the construction of complex molecules with continuous chiral centers.
We developed a highly regio‐, stereo‐, and enantioselective CuI‐catalyzed ring‐opening/B−H bond insertion reaction between 1‐silylcyclopropenes and borane adducts, which represents the first highly enantioselective carbene insertion reaction of α‐silylcarbenes, and enriches the accesses and type of chiral gem‐bimetallic reagents.
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•The state-of-art lignocellulose pretreatment was comprehensively reviewed.•The advances in bioenergy production from pretreated lignocellulose was described.•The review covers key ...challenges associated with the lignocellulose pretreatment.•New strategies for overcoming pretreatment barriers were highlighted.
As a clean and renewable energy, bioenergy is one of the most promising alternatives to fossil fuels. Lignocellulose possesses great potential for bioenergy production, but the recalcitrant and heterogeneous structure limits its application. Pretreatment technology offers an effective solution to fractionate the main components of the lignocellulose and uncover the available cellulose. The obtained feedstock can be applied to bioconversion into energy, e.g., bioethanol, biogas, biohydrogen, etc. Here, the current state of lignocellulose pretreatment technologies was comprehensively reviewed, the advances in bioenergy production from pretreated lignocellulose was described, with particular attention to key challenges involved. Several new strategies for overcoming pretreatment barriers to realize highly efficient lignocellulose bioconversion were highlighted. The insights given in this review will facilitate further development on lignocellulosic bioenergy production, towards addressing the global energy crisis and climate change related to the use of fossil fuels.
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