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Electrochemistry has recently emerged as a sustainable approach for efficiently generating radical intermediates utilizing eco-friendly electric energy. An electrochemical process was developed to transform 1,2,4-oxadiazolines under mild conditions. The electrochemical N-O bond cleavage at a controlled oxidation potential led to the selective synthesis of quinazolinone derivatives that could not be obtained by photocatalytic radical processes, indicating complementary reactivities in radical processes. The electrochemical reaction pathways were fully revealed by density functional theory-based investigations.

Background Woody plants with high glucose content are alternative bioresources for the production of biofuels and biochemicals. Various pretreatment methods may be used to reduce the effects of retardation factors such as lignin interference and cellulose structural recalcitrance on the degradation of the lignocellulose material of woody plants. Results A hydrogen peroxide-acetic acid (HPAC) pretreatment was used to reduce the lignin content of several types of woody plants, and the effect of the cellulose structural recalcitrance on the enzymatic hydrolysis was analyzed. The cellulose structural recalcitrance and the degradation patterns of the wood fibers in the xylem tissues of Quercus acutissima (hardwood) resulted in greater retardation in the enzymatic saccharification than those in the tracheids of Pinus densiflora (softwood). In addition to the HPAC pretreatment, the application of supplementary enzymes (7.5 FPU cellulase for 24 h) further increased the hydrolysis rate of P. densiflora from 61.42 to 91.94% whereas the same effect was not observed for Q. acutissima. It was also observed that endoxylanase synergism significantly affected the hydrolysis of P. densiflora. However, this synergistic effect was lower for other supplementary enzymes. The maximum concentration of the reducing sugars produced from 10% softwood was 89.17 g L−1 after 36 h of hydrolysis with 15 FPU cellulase and other supplementary enzymes. Approximately 80 mg mL−1 of reducing sugars was produced with the addition of 7.5 FPU cellulase and other supplementary enzymes after 36 h, achieving rapid saccharification. Conclusion HPAC pretreatment removed the interference of lignin, reduced structural recalcitrance of cellulose in the P. densiflora, and enabled rapid saccharification of the woody plants including a high concentration of insoluble substrates with only low amounts of cellulase. HPAC pretreatment may be a viable alternative for the cost-efficient production of biofuels or biochemicals from softwood plant tissues.

White sugar is the main commodity used to feed honey bees during the off-season as a nectar substitute. However, the price of sugar is increasing every year, thereby making bee keeping an expensive enterprise. Hence, it is necessary to find an alternative bee feed that is cheaper than sugar. The study aims to determine the potential of an alternative bee feed from renewable resources using onion waste (OW), which has a similar sugar composition to that of honey. The OW produces biosugar from in-house produced enzymes at a 90% conversion rate. The efficiency of enzymatic hydrolysis increases by more than 2 times after popping pretreatment. Furthermore, a removal rate of 98.5% for sulfur compounds, which caused the distinctive smell of onion, is obtained using a continuous column process with an activated carbon-containing alginate bead (AC-AB) adsorbent. In addition, after popping pretreatment and continuous AC-AB adsorbent column treatment, the feed intake is increased and the mortality is decreased by 3.2 times compared to that of none-popping and desulfurization treatment. Moreover, the combination of alternative feed with pollen decreases the mortality rate to almost 5.4 times. The results clearly demonstrates that OW can be a possible alternative feed source for honey bees.

A Ni-catalyzed reaction was developed for the synthesis of multifunctionalized indoles. The reaction proceeded through oxidative cyclization of the Ni(0)/P^N complex with an enyne system, 2-alkynyl anilinoacrylate, to provide a nickelacycle intermediate. The trans-carboamination around the internal alkyne was achieved by syn/anti-rotation of the Ni-carbenoid intermediate formed by C-N bond cleavage of the nickelacycle, and 3-alkenylated indoles were formed by C-N bond-forming reductive elimination. Notably, the synthesized indoles could be successfully transformed to functionalized carbazoles.

An unconventional approach for intermolecular direct C(sp3)-N radical coupling has been developed by photocatalytic C(sp3)-H activation of simple alkyl substrates using O-benzoyl oximes. The selective photocatalytic energy-transfer-driven homolysis followed by decarboxylation generates the persistent iminyl radical and aryl radical, which would undergo an unprecedented intermolecular hydrogen atom abstraction from the alkyl substrate to provide the key C(sp3) radical. Selective radical-radical C-N cross-coupling furnishes imines which are valuable amine building blocks.

Subtle differences in reaction conditions facilitated unprecedented photocatalytic reactions of oxadiazolines by energy transfer catalysis. A set of compounds, sulfoximines and benzimidazoles, were ingeniously prepared from oxadiazolines via nitrene intermediates by photocatalytic N-O/C-N bond cleavages. The synthesis of sulfoximines was realized through intermolecular N-S bond formation between nitrene intermediates and sulfoxides, whereas benzimidazoles were obtained via intramolecular aromatic substitution of the nitrene to the tethered aryl substituent.

Reductive N–O bond cleavage has been widely explored for providing either N or O radical species for various coupling processes. Despite significant advances, this photoredox pathway is less appeal...

BiVO4 crystals synthesized by an ultrasonic-assisted method (Sono-BiVO4 ) showed improved efficiency as a heterogeneous photocatalyst under visible-light irradiation. Sono-BiVO4 was successfully used for the C-C bond cleavage of alkenes to generate carbonyl compounds. Styrene derivatives were converted into carbonyl compounds in the presence of Sono-BiVO4 under highly sustainable conditions requiring only natural sources, that is, molecular oxygen, visible light, and water at room temperature. Additionally, Sono-BiVO4 could be easily separated from the reaction mixture and reused.

Melanoma is one of the skin cancers caused by various causes. Since the patients often do not feel pain that melanoma is mistaken for benign skin diseases. However, melanoma has the risk of multiplying rapidly and spreading easily through metastasis. It is important to treat it through chemo- or radiotherapy after surgical resection. Immunotherapy is a relatively new cancer treatment, which has shown longer survival rates than conventional cancer treatments in some cases. Cytokines or immune checkpoint blockers are the common immunotherapy strategies for melanoma. However, there are still melanoma patients who have not been benefited by immunotherapies. To overcome the limitations of current immunotherapy approaches, studies are underway to find new immunomodulators and various combinational immunotherapies. In this review, the existing treatments for melanoma are introduced and efforts to find optimal immunotherapy conditions for melanoma treatment have been summarized. Attempts to study the immunotherapy of melanoma with biochip technologies that simulate the body's microenvironment have also been summarized.

BACKGROUND: The cost of biomass feedstock represents a large portion of the total cost of bioethanol production. Therefore, it is necessary to find candidate materials as cheap feedstock for bioethanol production. Mangosteen pericarp waste (MPW) has potential as a feedstock for the production of bioethanol and other valuable chemicals. RESULTS: We have developed a new method to efficiently convert MPW into bioethanol and other valuable products such as biosugar, α‐mangostin and γ‐mangostin. The biosugar was obtained from in‐house produced cellulase and pectinase at a 90% conversion rate; the biosugar was converted into bioethanol with 75% yield using separate hydrolysis and fermentation. In addition, the extraction of α‐mangostin increased 1.46‐fold after a combination of popping pretreatment and enzymatic hydrolysis. A copper‐doped magnetic nanomatrix (Cu‐MNM) was utilized to purify α‐mangostin from MPW. We also obtained a good yield of γ‐mangostin via o‐demethylation reaction of α‐mangostin. CONCLUSION: The value of MPW can be increased through reuse to produce bioethanol and other valuable active materials such as biosugar, α‐mangostin and γ‐mangostin. We predict that economically beneficial processes could be developed from the reuse of these waste materials. © 2018 Society of Chemical Industry

A fluoroalkenylation of boronic acids with fluoroalkyl alkenes has been developed. The Pd-catalyzed oxidative Heck coupling reaction proceeds under an oxygen atmosphere at room temperature, in the absence of a base and/or a ligand, showing excellent practicality of the process. This simple transformation is highly stereoselective to provide only E-isomers. In addition to the general approach using alkenes with functionalized fluoroalkyl reagents, this method, by transferring an aromatic system to the electron-deficient fluoroalkyl alkene, provides an efficient alternative method to yield valuable organofluorines.

In this research, novel biorefinery processes for obtaining value-added chemicals such as biosugar and hesperidin from mandarin peel waste (MPW) are described. Herein, three different treatment methods were comparatively evaluated to obtain high yields of biosugar and hesperidin from MPW. Each method was determined by changes in the order of three processing steps, i.e., oil removal, hesperidin extraction, and enzymatic hydrolysis. The order of the three steps was found to have a significant influence on the production yields. Biosugar and hesperidin production yields were highest with method II, where the processing steps were performed in the following order: oil removal, enzymatic hydrolysis, and hesperidin extraction. The maximum yields obtained with method II were 34.46 g of biosugar and 6.48 g of hesperidin per initial 100 g of dry MPW. Therefore, the methods shown herein are useful for the production of hesperidin and biosugar from MPW. Furthermore, the utilization of MPWs as sources of valuable materials may be of considerable economic benefits and has become increasingly attractive.

The use of a visible light absorbing intermediate as a photosensitizer makes a chemical process simple and sustainable, obviating the need for the use of chemical additives. Herein, the formation of a photosensitizing disulfide in benzothiazole synthesis from 2-aminothiophenol and aldehydes was proposed and confirmed through in-depth mechanistic studies. A series of photophysical and electrochemical investigations revealed that an in situ-generated disulfide photosensitizes molecular oxygen to generate the key oxidants, singlet oxygen and superoxide anion, for the dehydrogenation step.

Here, we report an increase in biomass yield and saccharification in transgenic tobacco plants (Nicotiana tabacum L.) overexpressing thermostable &beta, glucosidase from Thermotoga maritima, BglB, targeted to the chloroplasts and vacuoles. The transgenic tobacco plants showed phenotypic characteristics that were significantly different from those of the wild-type plants. The biomass yield and life cycle (from germination to flowering and harvest) of the transgenic tobacco plants overexpressing BglB were 52% higher and 36% shorter than those of the wild-type tobacco plants, respectively, indicating a change in the genome transcription levels in the transgenic tobacco plants. Saccharification in biomass samples from the transgenic tobacco plants was 92% higher than that in biomass samples from the wild-type tobacco plants. The transgenic tobacco plants required a total investment (US$/year) corresponding to 52.9% of that required for the wild-type tobacco plants, but the total biomass yield (kg/year) of the transgenic tobacco plants was 43% higher than that of the wild-type tobacco plants. This approach could be applied to other plants to increase biomass yields and overproduce &beta, glucosidase for lignocellulose conversion.

A method has been developed for the synthesis of fluoroalkylated oximes, potential fluoroalkyl building-blocks for the synthesis of various organofluorine compounds, from easily available amino substrates and fluoroalkylated alkenes. tBuONO was utilized both as a diazotizing agent and as a NO radical source for the oxime synthesis in the process, and the use of a photocatalyst under visible-light irradiation increased the efficiency of the reaction. Various fluoroalkylated oximes were prepared by a tandem process of aryl radical addition to fluoroalkylated alkene and consecutive oxime generation process, albeit in moderate yields. This differentiated approach, transferring an aromatic system into an electron-deficient fluoroalkylated alkene, expands the scope of substrates where electron-poor aromatic systems could be utilized.

A transition-metal-free procedure for the synthesis of a highly valuable class of heteroaromatics, quinazolines, was developed by using easily available 2-aminobenzylamines and α,α,α-trihalotoluenes. The transformation proceeded smoothly in the presence of only sodium hydroxide and molecular oxygen in water at 100 °C, furnishing a variety of 2-aryl quinazolines. The crystallization process of the crude reaction mixture for the purification of the solid products circumvents huge solvent-consuming workup and column chromatographic techniques, which make the overall process more sustainable and economical.

Functionalized benzo[c]cinnoline derivatives were synthesized from easily accessible 2,2-diamino-1,1′-biaryls using a nitrite source. In this simple process, various functional groups were tolerated under mild reaction conditions, and the practicality of the process was demonstrated through the gram-scale production of the benzo[c]cinnolines.

A new Cu2+-selective reaction-based fluorescent probe 1 based on the semicarbazide-bearing derivative of 2-(2-aminophenyl)benzothiazole has been developed. Designed probe 1 exhibited turn-on-type fluorescence signaling behavior that was more prominent toward Cu2+ ions than to other environmentally relevant metal ions. The signaling of probe 1 was due to the Cu2+-induced hydrolysis of semicarbazide moiety to form its strongly fluorescent parent dye. Cu2+ signaling of probe 1 was not influenced by the presence of commonly encountered metal ions, and the detection limit was 1.71 × 10−8 M (1.1 ppb). As a practical application, the determination of Cu2+ in simulated semiconductor wastewater was conducted using a smartphone as a portable signal detection tool. For the color test analysis, enhanced reproducibility of Cu2+-sensing was realized using the grayscale image rather than the red, green, or blue channel image.

A visible-light-induced synthesis of N-H carbazoles from easily accessible 2,2′-diaminobiaryls in the absence of any external photosensitizer is reported. The process only requires tBuONO and natural resources, visible light, and molecular oxygen for the synthesis of N-H carbazoles. Experimental and computational studies support that the in situ formation of a visible-light-absorbing photosensitizing intermediate, benzocinnoline N-imide, is responsible for the activation of triplet molecular oxygen to singlet oxygen that, in turn, promotes the synthesis of carbazole.

Halogenated organic compounds are important anthropogenic chemicals widely used in chemical industry, biology, and pharmacology; however, the persistence and inertness of organic halides cause human health problems and considerable environmental pollution. Thus, the elimination or replacement of halogen atoms with organic halides has been considered a central task in synthetic chemistry. In dehalogenation reactions, the consecutive single-electron transfer from reducing agents generates the radical and corresponding carbanion and thus removes the halogen atom as the leaving group. Herein, we report a new strategy for an efficient chemoselective hydrodehalogenation through the formation of stable carbanion intermediates, which are simply achieved by using highly mobile two-dimensional electrons of inorganic electride [Ca2N]+·e– with effective electron transfer ability. The consecutive single-electron transfer from inorganic electride [Ca2N]+·e– stabilized free carbanions, which is a key step in achieving t...

Visible-light-induced trifluoromethylation reactions of alkenes with CF3I in the presence of Nile red, which acted as an organic photosensitizer, have been developed. Compared to trifluoromethylations with transition-metal-based photosensitizers like Ru and Ir complexes, the use of Nile red made this process more environmentally benign, not only by avoiding issues associated with metal residues, but also by allowing the use of low-energy photons (yellow LEDs) owing to its light absorbance at long wavelengths (440–600 nm). In the process, trifluoromethylated alkene and trifluoromethylated iodoalkane products were selectively synthesized by controlling the reaction conditions. In particular, the base employed significantly affected the selectivity of the process. The iodotrifluoromethylation of alkynes and the trifluoromethylation of N-heterocycles also proceeded well using Nile red. Furthermore, it was found that a .CF3 radical could be generated in the absence of Nile red under a higher photon energy by visible-light-induced electron transfer between tertiary amines and CF3I, despite the lower reactivity.

Photodynamic therapy is an emerging noninvasive cancer treatment approach, which requires a photosensitizer (PS), light, and molecular oxygen. In this study, we have successfully fabricated a dual nature (pH- and reactive-oxygen-species-responsive) upconversion nanoparticles (UCNPs) to utilize coloaded doxorubicin (DOX) and chlorin e6 (Ce6) with high antitumor efficacy. The model anticancer drug (DOX) and PS (Ce6) were conjugated in a ratio of 1:1 (w:w), and then loaded on the surface of UCNPs@mesoporous silica (mSiO2) (85.63 ± 9.87 nm). Cellular uptake could be achieved by either increased permeability or ionic effect of UCNPs@mSiO2, where Ce6 controlled the DOX release under a near-infrared (NIR) laser irradiation at 980 nm. A cytotoxicity analysis revealed that the dual-responsive UCNPs@mSiO2 could successfully deliver DOX and Ce6 at the tumor site, causing cell death with a high efficiency. This study shows that the modified UCNPs@mSiO2 is a promising system to realize NIR-light-triggered PS and drug delivery approach to improve synergistic therapies in vitro and in vivo, in the future.

Tri(9-anthryl)borane was successfully applied as an organophotocatalyst for the visible-light-induced trifluoromethylation of unactivated alkenes with CF3I. The mild reaction conditions tolerated a variety of functional groups, and the reaction could be extended to perfluoroalkylations with C3F7I and C4F9I. Mechanistic studies revealed that the photoredox catalysis involves an oxidative quenching pathway.

An unconventional nickel-catalyzed reaction was developed for the synthesis of multifunctionalized benzofurans from alkyne-tethered phenolic esters. The transformation involves the generation of a nucleophilic vinyl NiII species by the regioselective syn-aryl nickelation of an alkyne, which then undergoes an intramolecular cyclization with phenol ester to yield highly functionalized 1,1-disubstituted alkenes with 3-benzofuranyl and (hetero)aryl substituents. The methodology can be used for the late-stage benzofuran incorporation of various drug molecules and natural products, such as 2-propylvaleric acid, gemfibrozil, biotin, and lithocholic acid. Furthermore, this arylative cyclization method was successfully applied for the efficient synthesis of the anti-arrhythmic drug amiodarone.

The photoredox catalytic coupling of halomethyl arenes to bibenzyl derivatives has been demonstrated. The catalytic protocol employed the Hantzsch ester, potassium phosphate, and a photoactive cyclometalated IrIII complex catalyst. A photochemical quantum yield as high as 20 % was obtained. The catalytic mechanism was investigated in detail by performing photophysical and electrochemical measurements, as well as by quantum chemical calculations. The results suggest that two-electron mediation might be responsible for the improved photon economy. The reaction protocol was compatible with halomethyl arenes that contain a variety of functional groups. Finally, the synthetic utility of our protocol was demonstrated by the preparation of a natural dihydrostilbenoid, brittonin A.

Jack bean (JB, Canavalia ensiformis) is the source of bio-based products, such as proteins and bio-sugars that contribute to modern molecular biology and biomedical research. In this study, the use of jack bean was evaluated as a source for concanavalin A (Con A) and bio-sugar production. A novel method for purifying Con A from JBs was successfully developed using a glucosylated magnetic nano matrix (GMNM) as a physical support, which facilitated easy separation and purification of Con A. In addition, the enzymatic conversion rate of 2% (w/v) Con A extracted residue to bio-sugar was 98.4%. Therefore, this new approach for the production of Con A and bio-sugar is potentially useful for obtaining bio-based products from jack bean.

A simple and practical method for the synthesis of substituted oxazoles has been developed using readily available α-bromoketones and benzylamines by visible-light photocatalysis at room temperature. The process, which requires 1 mol % of [Ru(bpy)3]Cl2 photocatalyst with K3PO4 and CCl3Br, is effective for accessing a variety of valuable oxazole compounds. The synthetic utility of our protocol was also demonstrated by preparing a natural product, texaline.

Photoredox catalysis has emerged as a valuable alternative to dark-state catalysis. For the full potential of photoredox catalysis to be utilized, it is imperative to make use of low-energy photons in photoinduced radical processes. We have demonstrated that the use of oxalate as a coreactant provides a useful principle for the photocatalytic production of trifluoromethyl radicals (•CF3) from CF3I upon green or red LED photoirradiation of narrow-bandgap photocatalysts. The photocatalytic cycle involves a radical anion of carbon dioxide (CO2(•-)) as a reductant for CF3I, which is generated through photoinduced oxidative decarboxylation of oxalate. Electrochemical characterizations and steady-state and transient photophysical investigations were performed to reveal that there are two photoinduced electron-transfer pathways for oxalate-mediated •CF3 generation.

Two types of allylic trifluoromethylated compounds were synthesized by reacting alkynes with CF3CH2I using visible-light photocatalysis. Subtle differences in the catalytic system controlled the selectivity of iodotrifluoroethylation and hydrotrifluoroethylation. The iodotrifluoroethylated products were obtained in the presence of [Ru(bpy)3]Cl2 and TMEDA in CH3CN under visible-light irradiation, whereas hydrotrifluoroethylated products were synthesized using fac-[Ir(ppy)3] and a mixture of DBU and K2CO3 in DMF. The iodotrifluoroethylation reaction worked particularly well, even at gram-scale, and the synthetic utility of iodotrifluoroethylated products was proved by their coupling reactions, providing complex CF3-containing products.

A method for visible-light-induced synthesis of polyheteroaromatics from 2-heteroaryl-substituted anilines and heteroarylalkynes was developed. The process, which uses fac-Ir(ppy)3 as the photocatalyst and (t)BuONO as the diazotization reagent, is highly regioselective.

Dwindling petroleum resources and increasing environmental concerns have stimulated the production of platform chemicals via biochemical processes through the use of renewable carbon sources. Various types of biomass wastes, which are biodegradable and vastly underutilized, are generated worldwide in huge quantities. They contain diverse chemical constituents, which may serve as starting points for the manufacture of a wide range of valuable bio-derived platform chemicals, intermediates, or end products via different conversion pathways. The valorization of inexpensive, abundantly available, and renewable biomass waste could provide significant benefits in response to increasing fossil fuel demands and manufacturing costs, as well as emerging environmental concerns. This review explores the potential for the use of available biomass waste to produce important chemicals, such as monosaccharides, oligosaccharides, biofuels, bioactive molecules, nanocellulose, and lignin, with a focus on commercially viable technologies.

Fluoroalkylated alkynes, which are versatile building blocks for the synthesis of various biologically active organofluorine compounds, were synthesized from easily available alkynyl halides and fluoroalkyl halides by visible-light photocatalysis. Addition of fluoroalkyl radicals to alkynes and subsequent dehalogenation selectively yielded fluoroalkylated alkynes.

Spent coffee grounds (SCG) or coffee residue wastes (CRW) provide excellent raw material for mannose and bioethanol production. In this study, SCG were used to produce valuable biosugars, including oligosaccharides (OSs), manno-oligosaccharides (MOSs), mannose, and bioethanol. SCG were subjected to delignification and defatting, producing SCG-derived polysaccharides. Two-stage enzymatic hydrolysis (short- and long-term) was performed to produce short-chain manno-oligosaccharides (MOSs) and monosaccharides (MSs), respectively. From 100 g dry weight (DW) amounts of SCG, approximately 77 g delignified SCG and 61 g SCG-derived polysaccharides, amounts of 15.9 g of first biosugars (mostly MOSs), 25.6 g of second biosugars (mostly MSs), and 3.1 g of bioethanol, were recovered. This technique may aid in the production of high-value mannose and OSs from SCG and other lignocellulosic biomasses that contain specific polysaccharides.

Two transformations initiated by photoinduced one-electron transfer to α-bromo ketones have been demonstrated. Hantzsch esters donate one electron to α-bromo ketones under photoirradiation, promoting reductive debromination. Subsequent reactions of the resulting radical species of the ketones with molecular oxygen and Hantzsch esters lead to α-hydroxylation or debromination, respectively. The relative dominance of the two pathways depends profoundly on the reaction conditions, including solvent, O2 levels, and the concentration of the Hantzsch esters. The synthetic protocols feature advantages because they require the environmentally benign sources, molecular oxygen and visible light.

Recently, the development of eco-friendly radical processes has become of great interest in synthetic chemistry. In particular, visible-light photocatalysis has drawn tremendous attention for its environmental compatibility and versatility in promoting many synthetically important reactions. In addition, inorganic electrides as electron donors have emerged as new eco-friendly tools for radical transformations since they consist of non-toxic and naturally abundant main metals such as calcium. The design of new fluoroalkylation reactions has benefited greatly from recent advances in visible-light photocatalysis and the chemistry of inorganic electrides. Since adding fluoroalkyl groups can dramatically change the physical and chemical properties of organic compounds, using these processes to promote eco-friendly radical fluoroalkylations will have a major impact in areas such as pharmaceuticals, agrochemicals, and material sciences. This Personal Account reviews radical-mediated fluoroalkylations, such as trifluoromethylations and difluoroalkylations, recently developed in our laboratory.

(Hetero)aryloxytetrafluoroethylation of heteroaromatics and alkenes has been achieved by visible-light photocatalysis utilizing readily synthesized oxyfluoroalkyl reagents. The mild reaction conditions and the high diversity on both substrates and oxyfluoroalkyl reagents make this a useful method for late-stage modifications in the development of various functional molecules.

A novel, integrated process for economical high-yield production of d-mannose and ethanol from coffee residue waste (CRW), which is abundant and widely available, was reported. The process involves pretreatment, enzymatic hydrolysis, fermentation, color removal, and pervaporation, which can be performed using environmentally friendly technologies. The CRW was pretreated with ethanol at high temperature and then hydrolyzed with enzymes produced in-house to yield sugars. Key points of the process are: manipulations of the fermentation step that allowing bioethanol-producing yeasts to use almost glucose and galactose to produce ethanol, while retaining large amounts of d-mannose in the fermented broth; removal of colored compounds and other components from the fermented broth; and separation of ethanol and d-mannose through pervaporation. Under optimized conditions, approximately 15.7g dry weight (DW) of d-mannose (approximately 46% of the mannose) and approximately 11.3g DW of ethanol from 150g DW of ethanol-pretreated CRW, were recovered.

Despite the increasing understanding of the crucial roles of glutathione (GSH) in cellular defense against heavy metal stress as well as oxidative stress, little is known about the functional role of exogenous GSH in mercury (Hg) tolerance in plants. Here, we provide compelling evidence that GSH contributes to Hg tolerance in diverse plants. Exogenous GSH did not mitigate the toxicity of cadmium (Cd), copper (Cu), or zinc (Zn), whereas application of exogenous GSH significantly promoted Hg tolerance during seed germination and seedling growth of Arabidopsis thaliana, tobacco, and pepper. By contrast, addition of buthionine sulfoximine, an inhibitor of GSH biosynthesis, severely retarded seed germination and seedling growth of the plants in the presence of Hg. The effect of exogenous GSH on Hg specific tolerance was also evident in the presence of other heavy metals, such as Cd, Cu, and Zn, together with Hg. GSH treatment significantly decreased H2O2 and O2- levels and lipid peroxidation, but increased chlorophyll content in the presence of Hg. Importantly, GSH treatment resulted in significantly less accumulation of Hg in Arabidopsis plants, and thin layer chromatography and nuclear magnetic resonance analysis revealed that GSH had much stronger binding affinity to Hg than to Cd, Cu, or Zn, suggesting that tight binding of GSH to Hg impedes Hg uptake, leading to low Hg accumulation in plant cells. Collectively, the present findings reveal that GSH is a potent molecule capable of conferring Hg tolerance by inhibiting Hg accumulation in plants.

Herein we report an extended study of [4 + 2] benzannulation reactions of 2-(hetero)aryl-substituted anilines with alkynes by visible light photocatalysis. The method requires the use of tBuONO as a diazotizing agent and 0.3 mol % of fac-Ir(ppy)3 as a photocatalyst at room temperature. The reaction proceeded in a chemo- and regioselective manner with high functional group tolerance under mild conditions allowing the preparation of a wide variety of polycyclic (hetero)aromatic compounds, including phenanthrenes, in moderate to high yields. This procedure is amenable to gram-scale synthesis of 9-phenylphenanthrene.

ConspectusOwing to their unique biological, physical, and chemical properties, fluoroalkylated organic substances have attracted significant attention from researchers in a variety of disciplines. Fluoroalkylated compounds are considered particularly important in pharmaceutical chemistry because of their superior lipophilicity, binding selectivity, metabolic stability, and bioavailability to those of their nonfluoroalkylated analogues. We have developed various methods for the synthesis of fluoroalkylated substances that rely on the use of visible-light photoredox catalysis, a powerful preparative tool owing to its environmental benignity and mechanistic versatility in promoting a large number of synthetically important reactions with high levels of selectivity.In this Account, we describe the results of our efforts, which have led to the development of visible-light photocatalytic methods for the introduction of a variety of fluoroalkyl groups (such as, −CF3, −CF2R, −CH2CF3, −C3F7, and −C4F9) and arylthi...

Cyclopenta-fused polycyclic aromatic hydrocarbons (CP-PAHs), potentially electronically and biologically highly active materials, were synthesized from readily available 2-aryl-substituted anilines. Reactions occur under extremely mild, room temperature conditions using (t)BuONO as the sole reagent. The use of a nitrite source generates a reactive diazonium intermediate in situ that then reacts with a tethered polycyclic aromatic moiety by intramolecular aromatic substitution. This protocol could be presented as one of the simplest methods to access CP-PAHs.

Visible-light-induced arylthiofluoroalkylations of unactivated heteroaromatics and alkenes have been developed utilizing readily available arylthiofluoroalkyl sources. This method enables simultaneous installation of sulfur and fluoroalkyl moieties, two important functional groups, which demonstrates its potential use for late-stage modifications in the synthesis of functional molecules. This method can be easily utilized to fine-tune the properties of lead molecules in drug development by controlling the number of fluorine atoms in the reagents.

An efficient visible-light photocatalysis-based one-pot amide synthesis method was developed; visible-light irradiation of a mixture of an aldehyde, tert-butyl hydrogen peroxide, and N-chlorosuccinimide using a Ru(bpy)3Cl2 photocatalyst afforded an acid chloride, which subsequently reacted with amine to yield the corresponding amide. The reaction was used to synthesize moclobemide and a D3 receptor intermediate.

A molecular dyad that can photosensitize and visualize singlet oxygen ((1)O2) was developed. The dual photofunction enables ratiometric photoluminescence monitoring of the progress of (1)O2-induced cell death.