Targeted Stimulation of Micropores by CS2 Extraction on Molecular of Coal.

The targeted stimulation of micropores based on the transformation of coal's molecular structure is proposed due to the chemical properties and difficult-to-transform properties of micropores. Carbon disulfide (CS2) extraction is used as a targeted stimulation to reveal the internal evolution mechanism of micropore transformation. The variations of microcrystalline structures and micropores of bituminous coal and anthracite extracted by CS2 were analyzed with X-ray diffraction (XRD), low-temperature carbon dioxide (CO2) adsorption, and molecular simulation. The results show that CS2 extraction, with the broken chain effect, swelling effect, and aromatic ring rearrangement effect, can promote micropore generation of bituminous coal by transforming the microcrystalline structure. Furthermore, CS2 extraction on bituminous coal can decrease the average micropore size and increase the micropore volume and area. The aromatic layer fragmentation effect of CS2 extraction on anthracite, compared to the micropore generation effect of the broken chain effect and swelling effect, can enlarge micropores more remarkably, as it induces an enhancement in the average micropore size and a decline in the micropore volume and area. The research is expected to provide a theoretical basis for establishing reservoir stimulation technology based on CS2 extraction.

Mitochondrial transfer of α-synuclein mediates carbon disulfide-induced mitochondrial dysfunction and neurotoxicity.

Exposure to carbon disulfide (CS2) is a recognized risk factor in the pathogenesis of Parkinson's disease, yet the underlying mechanisms of deleterious effects on mitochondrial integrity have remained elusive. Here, through establishing CS2 exposure models in rat and SH-SY5Y cells, we demonstrated that highly expressed α-synuclein (α-Syn) is transferred to mitochondria via membrane proteins such as Tom20 and leads to mitochondrial dysfunction and mitochondrial oxidative stress, which ultimately causes neuronal injury. We first found significant mitochondrial damage and oxidative stress in CS2-exposed rat midbrain and SH-SY5Y cells and showed that mitochondrial oxidative stress was the main factor of mitochondrial damage by Mitoquinone intervention. Further experiments revealed that CS2 exposure led to the accumulation of α-Syn in mitochondria and that α-Syn co-immunoprecipitated with mitochondrial membrane proteins. Finally, the use of an α-Syn inhibitor (ELN484228) and small interfering RNA (siRNA) effectively mitigated the accumulation of α-Syn in neurons, as well as the inhibition of mitochondrial membrane potential, caused by CS2 exposure. In conclusion, our study identifies the translocation of α-Syn to mitochondria and the impairment of mitochondrial function, which has important implications for the broader understanding and treatment of neurodegenerative diseases associated with environmental toxins.

Palladium-anchored calix[4]arene-derived porous organic polymer towards efficient hydrolytic cleavage of carbon disulfide.

The release of carbon disulfide can have adverse effects on our environment and human health. The stability of carbon disulfide and the slow kinetics of hydrolysis can make it challenging to achieve efficient and practical cleavage of the CS bonds. Herein, a calix[4]arene-based porous organic polymer (CPOP-1) is innovatively synthesized through an optimized polycondensation reaction using C-Methylcalix[4]resorcinarene and hexafluoro-hexaazatriphenylene as monomers. Subsequently, palladium-induced calix[4]arene-based porous organic polymer was also synthesized via strong Pd-N coordination bonds to construct the metal-induced porous catalyst (CPOP-2). The polymeric catalyst active center [Pd2+(N^N)(NO3-)2] demonstrated outstanding catalytic hydrolysis performance (11.14 µmol g-1 h-1) in 10.5 h which is significantly enhanced by ca.13.2 times as compared to reported mononuclear Bpy-Pd(NO3)2, and 7.07 times than model trinuclear complex catalyst HATN-Pd-1, respectively. The control experiments revealed that POP catalysts showcased robust stability, prolonged effectiveness, and feasible recyclability during the hydrolytic cleavage of carbon disulfide at room temperature in aqueous solutions. Furthermore, the coordination environment of [Pd2+(N^N)] was validated through XPS, EXAFS, and isotope labeling measurements, and the hydrolysis cleavage products were confirmed e. g. CO2, sulfide, and protons. More importantly, a reaction mechanism was formulated coupled with theoretical calculations, and simulations. The proposed mechanism involves sequential OH- nucleophilic attacks on the carbon atoms of insert-coordinated CS2 and COS, leading to the cleavage of double CS bonds and the formation of CO bonds. The concurrent dissociation of the C-S bond and liberation of CO2 result in an intermediate structure characterized by [(N^N)Pd2+](SH-)2. This intermediate motif serves as the source of the thermodynamic driving force for the reaction.

Multi-omics analysis of nitrifying sludge under carbon disulfide stress: Nitrification performance and molecular mechanisms.

Carbon disulfide (CS2) is a widely used enzyme inhibitor with cytotoxic properties, commonly employed in viscose fibers and cellophane production due to its non-polar characteristics. In industry, CS2 is often removed by aeration, however, residual CS2 may enter the wastewater treatment plants, impacting the performance of nitrifying sludge. Currently, there is a notable dearth of research on the response of nitrifying sludge to CS2-induced stress. This study delves into the alterations in the performance of nitrifying sludge under short-term and long-term CS2 stress, scrutinizes the toxic effects of CS2 on microbial cells, elucidates the succession of microbial community structure, and delineates changes in microbial metabolic products. The findings from short-term CS2 stress revealed that low concentrations of CS2 induced oxidative stress damage, which was subsequently repaired in cells. However, at concentrations of 100-200 mg/L, CS2 inhibited reactive oxygen species, superoxide dismutase, and catalase, which are associated with metabolic and antioxidant activities. The inhibition of nitrite oxidoreductase activity by high concentrations of CS2 was attributed to its impact on the enzyme's conformation. Prolonged CS2 stress resulted in an increase in the secretion of soluble extracellular polymeric substances in sludge, while CS2 was assimilated into sulfate. The analysis of sludge microbial community structure revealed a decline in the relative abundance of Rhodanobacter, which is associated with nitrification, and an increase in Sinomonas, involved in sulfur oxidation. Metabolite analysis results demonstrated that high concentrations of CS2 affect pantothenate and CoA biosynthesis, purine metabolism, and glutathione metabolism. This study elucidated the microbial response mechanism of nitrifying sludge under short-term and long-term CS2 stress. It also clarified the composition and function of microbial ecosystems, and identified key bacterial species and metabolites. It provides a basis for future research to reduce CS2 inhibition through approaches such as the addition of metal ions, the selection of efficient CS2-degrading strains, and the modification of strain metabolic pathways.

Bioorthogonal Delivery of Carbon Disulfide in Living Cells.

Carbon disulfide (CS2) is an environmental contaminant, which is deadly hazardous to the workers under chronic or acute exposure. However, the toxicity mechanisms of CS2 are still unclear due to the scarcity of biocompatible donors, which can release CS2 in cells. Here we developed the first bioorthogonal CS2 delivery system based on the "click-and-release" reactions between mesoionic 1,3-thiazolium-5-thiolates (TATs) and strained cyclooctyne exo-BCN-OH. We successfully realized intracellular CS2 release and investigated the causes of CS2-induced hepatotoxicity, including oxidative stress, proteotoxic stress and copper-dependent cell death. It is found that CS2 can be copper vehicles bypassing copper transporters after reacting with nucleophiles in cytoplasm, and extra copper supplementation will exacerbate the loss of homeostasis of cells and ultimately cell death. These findings inspired us to explore the anticancer activity of CS2 in combination with copper by introducing a copper chelating group in our CS2 delivery system.

O/S Exchange Reaction in Synthesizing Sulfur-Containing Polymers.

Using carbon disulfide (CS2) and carbonyl sulfide (COS) as sulfur-containing and one-carbon feedstocks to make value-added products is paramount for both pure and applied chemistry and environmental science. One of the practical strategies is to copolymerize these bulk chemicals with epoxides to produce sulfur-containing polymers. This approach contributes to improving the sustainability of polymer manufacturing, provides highly desired functional polymer materials, and has attracted much attention. However, these copolymerizations invariably exhibit the intensely complicated chemistry of O/S exchange reaction, leading to sulfur-containing polymers with diverse architectures. As the understanding of O/S exchange continues to deepen, recent efforts have guided significant advances in the synthesis of CS2- and COS-based polymers. This review examines the O/S exchange chemistry and summarizes the recent progress in this field to promote the further advance of synthesizing sulfur-containing polymers from CS2 and COS.

Investigating local field tuning Fermi resonance of CS2 by Raman spectroscopy and DFT calculations.

In the spectroscopic study of polyatomic molecules, Fermi resonance (FR) is a vibrational coupling and energy transfer phenomenon that widely exists intra- and intermolecular. In particular, the FR coupling between the fundamental mode ν1 and the doubling mode 2ν2 of the CS2 molecule has attracted extensive research. In this work, we investigate the effect of local field on tuning the FR of CS2. By analyzing the Raman spectra of CS2 mixed with methanol and ethanol with different mole fractions, the results indicated that weak HBs interactions in binary solutions can be reflected by the linear frequency shift of the C-H bond vibrations (in methanol and ethanol) with different molar concentrations. Furthermore, the geometrical structure was optimized using DFT simulation, and the vibration analysis and interaction energy were carried out. The simulated Raman spectra are in good agreement with the experiments. In addition, high-pressure Raman spectra of CS2 were obtained by diamond anvil cell technique (up to 9.19 GPa) and a pressure-induced phase transition was observed at 1.71 GPa. The results demonstrated that the pressure-induced polymerization phase transition of CS2 molecules causes the close packing and more orderly arrangement of molecules, resulting in the enhancement of FR coupling. HB and high pressure tune the FR of the CS2 molecule differently.

Carbon disulfide induces accumulation of TDP-43 in the cytoplasm and mitochondrial dysfunction in rat spinal cords.

The relationship between environmental neurotoxicant exposure and neurodegenerative diseases is being extensively investigated. Carbon disulfide, a classic neurotoxicant and prototype of dithiocarbamates fungicides and anti-inflammatory agents, has been detected in urban adults, raising questions about whether exposure to carbon disulfide is associated with a high incidence of neurodegenerative diseases. Here, using rat models and SH-SY5Y cells, we investigated the possible mechanistic linkages between carbon disulfide neurotoxicity and the expression of TDP-43 protein, a marker of amyotrophic lateral sclerosis/frontotemporal lobar degeneration. Our results showed that rats exhibited severe dyskinesia and increased TDP-43 expression in the spinal cord following carbon disulfide exposure. Moreover, carbon disulfide exposure induced abnormal cytoplasmic localization and phosphorylation of TDP-43 in motor neurons. Importantly, carbon disulfide treatment led to the accumulation of TDP-43 in the mitochondria of motor neurons and resulted in subsequent mitochondrial damage, including mitochondrial structural disruption, mitochondrial respiratory chain complex I inhibition, and impaired VCP/p97-dependent mitophagy. In summary, our study provides support for carbon disulfide exposure-mediated TDP-43 mislocalization and mitochondrial dysfunction, contributes to understanding the pathogenesis of environmental neurotoxin-induced neurodegeneration, and provides inspiration for potential therapeutic strategies.

Heteroaromatization of Coumarin Part I: Design, Synthesis, Reactions, Antitumor Activities of Novel Pyridine and Naphthyridine Derivatives.

INTRODUCTION: A novel series of chromen-3-yl-pyridine moieties were synthesized. IR, NMR, and MS spectroscopy were used to confirm the structure of these novel compounds and study antitumor activity of these compounds. The structure-activity relationship investigation demonstrated that 2,4-diamino- 5-(3-methoxyphenyl)-7-(2-oxo-2H-chromen-3-yl)-1,8-naphthyridine-3-carbonitrile (16), naphthyridine- 3-carbonitrile derivatives 17, 18 and pyrido[2,3-d]pyrimidine derivative 12 were found to be more effective, while compounds 5a,b, 9c, 11, 13 and 14 showed moderate activity for antitumor activities. OBJECTIVES: The objective was to design a series of new chromen-3-yl-pyridine and pyrido[2,3-d]pyrimidine derivatives and study the antitumor of these compounds. MATERIALS AND METHODS: The condensation reaction of 3-acetyl-2H-chromen-2-one with 3-methoxy benzaldehyde and malononitrile or ethyl cyanoacetate in the presence of ammonium acetate and acetic acid under reflux to give the corresponding chromen-3-yl pyridine-3-carbonitrile derivatives. RESULTS: In this study, the antitumor activity of the synthesized compounds chromen-3-yl-pyridine derivatives has been determined for the broad spectrum of cytotoxic activity toward the investigated three cell lines and 5-Fluorouracil, as reference drugs. CONCLUSION: A series of new chromen-3-yl-pyridine and pyrido[2,3-d]pyrimidine derivatives were synthesized in this work. All compounds were evaluated for cytotoxic activity.

Effects of operating conditions on the in situ control of sulfur-containing odors by using a novel alternative landfill cover and its transformation mechanism.

Sulfur-containing gases are main sources of landfill odors, which has become a big issue for pollution to environment and human health. Biocover is promising for treating landfill odors, with advantages of durability and environmental friendliness. In this study, charcoal sludge compost was utilized as the main effective component of a novel alternative landfill cover and the in situ control of sulfur-containing odors from municipal solid waste landfilling process was simulated under nine different operating conditions. Results showed that five sulfur-containing odors (hydrogen sulfide, H2S; methyl mercaptan, CH3SH; dimethyl sulfide, CH3SCH3; ethylmercaptan, CH3CH2SH; carbon disulfide, CS2) were monitored and removed by the biocover, with the highest removal efficiencies of 77.18% for H2S, 87.36% for CH3SH, and 92.19% for CH3SCH3 in reactor 8#, and 95.94% for CH3CH2SH and 94.44% for CS2 in reactor 3#. The orthogonal experiment showed that the factors influencing the removal efficiencies of sulfur-containing odors were ranked from high to low as follows: temperature > weight ratio > humidity content. The combination of parameters of 20% weight ratio, 25°C temperature, and 30% water content was more recommended based on the consideration of the removal efficiencies and economic benefits. The mechanisms of sulfur conversion inside biocover were analyzed. Most organic sulfur was firstly degraded to reduced sulfides or element sulfur, and then oxidized to sulfate which could be stable in the layer as the final state. In this process, sulfur-oxidizing bacteria play a great role, and the distribution of them in reactor 1#, 5#, and 8# was specifically monitored. Bradyrhizobiaceae and Rhodospirillaceae were the dominant species which can utilize sulfide as substance to produce sulfate and element sulfur, respectively. Based on the results of OUTs, the biodiversity of these sulfur-oxidizing bacteria, these microorganisms, was demonstrated to be affected by the different parameters. These results indicate that the novel alternative landfill cover modified with bamboo charcoal compost is effective in removing sulfur odors from landfills. Meanwhile, the findings have direct implications for addressing landfill odor problems through parameter adjustment.

Hyphenated liquid electrode glow discharge-dielectric barrier discharge molecular emission spectrometry for determination of dithiocarbamates.

A hyphenated liquid electrode glow discharge (LEGD)-dielectric barrier discharge (DBD) molecular emission spectrometer was constructed and used as a novel liquid chromatography (LC) detector for dithiocarbamates (DTC) determination. The LEGD was used as an acidolysis reactor for the in-situ transformation of DTCs into CS2 with high efficiencies of 74.11-97.98%. The DBD was used to excite CS2 gas to generate a specific molecular emission at 257.94 nm. The linear correlation coefficient of the method was > 0.99 from 1 to 200 µg mL-1. The detection limits ranged from 0.1 to 0.3 µg mL-1 with 76-119% recovery and relative standard deviations of 0.2-8.5%. Moreover, the hyphenated microplasma spectrometer achieved low power consumption, low temperature, immediate acidolysis, and high transformational efficiency, and can detect each DTC when combined with LC.

Carbon disulfide removal from gasoline fraction using zinc-carbon composite synthesized using microwave-assisted homogenous precipitation.

Carbon disulfide (CS2) is one of the sulfur components that are naturally present in petroleum fractions. Its presence causes corrosion issues in the fuel facilities and deactivates the catalysts in the petrochemical processes. It is a hazardous component that negatively impacts the environment and public health due to its toxicity. This study used zinc-carbon (ZC) composite as a CS2 adsorbent from the gasoline fraction model component. The carbon is derived from date stone biomass. The ZC composite was prepared via a homogenous precipitation process by urea hydrolysis. The physicochemical properties of the prepared adsorbent are characterized using different techniques. The results confirm the loading of zinc oxide/hydroxide carbonate and urea-derived species on the carbon surface. The results were compared by the parent samples, raw carbon, and zinc hydroxide prepared by conventional and homogeneous precipitation. The CS2 adsorption process was performed using a batch system at atmospheric pressure. The effects of adsorbent dosage and adsorption temperatures have been examined. The results indicate that ZC has the highest CS2 adsorption capacity (124.3 mg.g-1 at 30 °C) compared to the parent adsorbents and the previously reported data. The kinetics and thermodynamic calculation results indicate the spontaneity and feasibility of the CS2 adsorption process.

Carbon disulfide exposure induced lung function reduction partly through oxidative protein damage: A cross-sectional and longitudinal analysis.

Carbon disulfide (CS2) exposure has been associated with lung function reduction in occupational population. However, evidence on the general population with relatively low CS2 exposure is lacking and the mechanism involved remains largely unknown. Urinary CS2 metabolite (2-mercaptothiazolidine-4-carboxylic acid, TTCA) and lung function were determined in the urban adults from the Wuhan-Zhuhai cohort at baseline in 2011-2012 and were repeated every 3 years. Cross-sectional and longitudinal associations between TTCA and lung function were estimated using linear mixed models. Inflammation and oxidative damage biomarkers in blood/urine were measured to evaluate their potential mediating roles involved. Cross-sectionally, participants in the highest quartile of TTCA level showed a 0.64% reduction in FEV1/FVC and a -308.22 mL/s reduction in PEF, compared to those in the lowest quartile. Longitudinally, participants with consistently high TTCA level had annually -90.27 mL/s decline in PEF, compared to those with consistently low TTCA level. Mediation analysis revealed that plasma protein carbonyl mediated 49.89% and 22.10% of TTCA-associated FEV1/FVC and PEF reductions, respectively. Conclusively, there was a cross-sectional and longitudinal association between CS2 exposure and lung function reduction in the general urban adults, and protein carbonylation (oxidative protein damage) partly mediated lung function reduction from CS2 exposure.

DNA Damage on Buccal Epithelial Cells, Personal Working in the Rubber Industry Occupationally Exposed to Carbon Disulfide (CS2).

INTRODUCTION: The most significant industrial utilization of carbon disulfide (CS2) has been in the manufacture of cellulose rayon, cellophane, and rubber industry. CS2 prompts expanded recurrence of chromosomal variations in laborers occupationally exposed to CS2. MATERIALS AND METHODS: In the current study, the DNA analysis was carried out from exfoliated buccal epithelial cells from rubber industry workers exposed to CS2 and an equal number of healthy control subjects. Both the control and experimental subjects were categorized by their smoking habits such as smokers (S) and non-smokers (NS). Furthermore, experimental subjects were further separated based on their exposure period. Students t-test statistical tools were used to analyze the final results. RESULTS: The present analysis identified a high frequency of DNA damage in rubber industry workers (16.55±0.43) than control subjects (9.8±0.21). Also, maximum number of DNA damage detected in smoking experimental group (18.27±0.02) than non-smoking experimental (15.02±0.01) and smoking control groups (10.25±0.04 ). CONCLUSION: Smoking habits synergistically increased the DNA damage in the rubber industry workers exposed to CS2.

Desulfurization of hydrophilic and hydrophobic volatile reduced sulfur with elemental sulfur production in denitrifying bioscrubber.

Volatile reduced sulfur compounds were odor and irritating toxic gas, which were commonly produced during waste and wastewater treatment. The autotrophic sulfide denitrifiers converted sulfide as alternative electron acceptor to reduce nitrate, which achieved simultaneous denitrification and sulfur oxidation. In this study, to investigate the effect of sulfur compounds solubility, S/N and oxygen on sulfur and nitrogen removal, a bioscrubber was studied for treatment of hydrophilic H2S and hydrophobic CS2. Both H2S and CS2 could be efficiently removed (99%), with the highest sulfide loading of 46.9 gS/m3·d. The elemental sulfur production was strongly correlated to S/N ratio (r = 0.969, p = 0.03), the highest elemental sulfur production efficiency achieved 92.0% under S/N ratio of 2.0 for treatment of H2S. Thiobacillus sp. bacteria was the pre-dominated sulfide-dependent denitrifiers (78.2%) before exposing to oxygen, while abundance of Cryseobacterium and unclassified Xanthomonadaceae aerobic sulfide oxidizer dramatically increased up to 40% and 7.3% after aeration. Remarkably increasing production of extracellular polymeric substance (197%) was observed after treatment of CS2, which might promote the hydrolysis of CS2 and stabilization of elemental sulfur. This study demonstrated the possibility to apply sulfide-dependent denitrification process for treatment of both hydrophilic and hydrophobic volatile reduced sulfur waste gas with elemental sulfur recovery.

Biogeochemical controls on climatically active gases and atmospheric sulfate aerosols in the western Pacific.

The Pacific Ocean plays an important role in regulating the budget of climatically active gases and the burden of sulfate aerosols. Here, a field investigation was conducted to clarify the key processes and factors controlling climatically active gases, including dimethyl sulfide (DMS), carbonyl sulfide (OCS), carbon disulfide (CS2), and carbon dioxide (CO2), in both surface seawater and the lower atmosphere of the western Pacific. In addition, the relative contributions of different sources to atmospheric sulfate aerosols were quantitatively estimated, and their causes were explored. The maximum concentrations of DMS, OCS and CS2 and the minimum partial pressure of CO2 (pCO2) were observed in the Kuroshio-Oyashio Extension. Kuroshio-induced mesoscale eddies brought abundant nutrients and organic matter from the subsurface layer of Oyashio into the euphotic layer, thus enhancing primary productivity and accelerating the photoreaction of organic matter. These processes led to higher concentrations of DMS, OCS and CS2 and lower pCO2. However, the oligotrophic subsurface layer in the subtropical gyre and the strong barrier layer in the equatorial waters suppressed the upward fluxes of nutrients and organic matter, resulting in lower surface concentrations of DMS, OCS, and CS2 in these areas. Being far from the continents, atmospheric concentrations of DMS, OCS and CS2 and pCO2 in the western Pacific generally were observed to depend on the local sea-to-air exchange and may be regulated by atmospheric oxidation and mixing of air masses. In general, oceanic DMS emissions played an important role in the formation of sulfate aerosols in the western Pacific (accounting for ∼19.5% of total sulfate aerosols), especially in the Kuroshio-Oyashio Extension (∼32.3%). These processes in seawater may also determine the variations and emissions of other climatically active gases from biogenic and photochemical sources.

Boraalkenes Made by a Hydroboration Route: Cycloaddition and B=C Bond Cleavage Reactions.

Hydroboration of styrene or vinylcyclohexane with the IMes(C6 F5 )BH+ cation followed by deprotonation provided a convenient synthetic entry to the [B]=CHCH2 R boraalkenes 9 a and 9 b. The in situ generated IMes(SCN)BH+ system reacted similarly with 1,1-diphenylethene followed by deprotonation to give the isothiocyanato substituted boraalkene 9 c. The boraalkenes underwent [2+2] cycloaddition reactions with a small series of heterocumulenes to give the respective four-membered heterocycles. The [B]=CHCH2 R+CO2 cycloadducts 13 a and 13 b added the borane HB(C6 F5 )2 with cleavage of the central B-C σ-bond. CS2 underwent an unusual reaction with the boraalkenes, namely insertion into the B=C bond with formation of the borylated dithioketene acetal under complete rupture of the strong B=C double bond. The intermediate dithiobora-ß-lactone type intermediate was isolated in the case of the isothiocyanato-boraalkene reaction and characterized by X-ray diffraction.

NaH-promoted one-pot synthesis of 5-amidoimidazoles from arylamines, carbon disulfide and isocyanides.

A novel, convenient and efficient protocol to access functionalized 5-amidoimidazoles is developed via one-pot synthesis from readily available materials of arylamines, carbon disulfide and isocyanides. The transformation was realized at room temperature and provided 5-amidoimidazoles in moderate to good yields in the presence of NaH. In addition, control experiments indicated that the process might be achieved via the base-induced cyclization of activated methylene isocyanides with N,N-disubstituted thioureas that produced from the reaction of amines and carbon disulfide.

Catalysts for gaseous organic sulfur removal.

Organic sulfur gases (COS, CS2 and CH3SH) are widely present in reducing industrial off-gases, and these substances pose difficulties for the recovery of carbon monoxide and other gases. The reaction pathways and reaction mechanisms of organic sulfur on different catalyst surfaces have yet to be fully summarized. The literature shows that many factors, such as catalyst synthesis method, loaded metal composition, number of surface hydroxyl groups, number of acid-base sites and methods of surface modification, have important effects on the catalytic performance of metal catalysts. Therefore, this paper presents a comprehensive review of the research on the application of catalysts such as zeolites, metal oxides, carbon-based materials, and hydrotalcite-like derivatives in the field of organic sulfur removal. Future research prospects are summarized, more in situ characterization experiments and theoretical calculations are needed for the catalytic decomposition of methanethiol to analyze the coke generation pathways at the microscopic level, while the simultaneous removal of multiple organic sulfur gases needs to be focused on. Based on previous catalyst research, we propose possible innovations in catalyst design, desulfurization technology and organic sulfur resource utilization technology.

Synthetic Procedures to Access 2-Guanidinobenzazoles of Biological Interest.

Benzazoles (Bz) and derivatives are interesting molecules in medicinal chemistry. Several of these compounds display diverse biological activities; some are still used in clinical applications. In this way, synthetic chemists are interested in developing new procedures to access compounds with the guanidine moiety as 2-aminobenzimidazole (2ABI), Astemizole (antihistaminic), Albendazole (anthelmintic) and Carbendazim (fungicide). The guanidine group, considered a super base bonded to a benzoxazole ring, results in the 2-guanidinobenzazoles (2GBZs), which could modify the biological activity of these heterocycles. On these bases, we prepared this review article, which covers chemical aspects of 2-guanidinobenzoazoles as potential therapeutic agents and summarizes the current knowledge on the mechanism of pharmacological activities such as cytotoxic, inhibition of cell proliferation via angiogenesis and apoptosis. Specifically, it highlights the most recent results of synthetic approaches to 2GBZs with variety of modifications and functionalization with aromatic, carbohydrate, and amino-acid moieties as illustrated on 28 schemes and is concluded with 141 references. Additionally, the format of this interesting review is exclusively designed on specifically classified category of chemical reactions with primary precursors such as o-substituted anilines and 2-aminobenzazoles (2ABZs). This will constitute the important goals and novelty of this paper to facilitate synthetic chemists in the investigation about development of new pharmacophores.