Concept: Organosulfur compounds
C-S bond activation, cleavage and transformations by means of transition metal compounds have recently become more and more important in the petroleum industry and synthetic chemistry. Homogeneous transition metal compounds have been investigated in order to provide the fundamental insight into the C-S bond cleavage in problematic organosulfur compounds such as thiophene, benzo- and dibenzothiophene derivatives. Rendering transition-metal mediated reactions with organosulfur compounds catalytic may provide promising routes to deep hydrodesulfurization of petroleum feedstocks, and offer potentially useful synthetic protocols for cross-couplings and biomimetic organic synthesis. During the last few decades increasing work was documented on C-S bond activation and transformations by means of transition metal compounds. This review summarizes the recent advances in C-S bond cleavage via the insertion of transition metals into the inert C-S bonds of these problematic organosulfur compounds, and transition-metal mediated C-S bond transformations via C-S activation through cross-couplings of thioesters, ketene dithioacetals, sulfonyl chlorides, and other diverse organosulfur compounds.
Desulfurization of fuels is receiving more and more attention all over the world due to the increase of stringent environmental regulations and fuel specifications. The metal-organic framework (MOF) is a new class of crystalline materials, and high porosity, one of the most important properties of MOFs, plays a central role in the functional properties. However, the investigation of MOFs, being employed as sorbents for adsorptive desulfurization, is still scarce. In this regard, we have constructed a new 3D porous compound 1 by using rigidly designed carboxylate ligands, which, for the first time, exhibit an unusual triple molecular necklace-like helix. The N(2) sorption isotherms of 1 show that it has a large Brunauer-Emmett-Teller (BET) surface area and pore volume. With the stable pore structure and appropriate pore sizes, compound 1 has been used as a sorbent for adsorptive desulfurization. The results indicate that compound 1 shows an excellent adsorption property and, more importantly, displays excellent stability, repeatability, and regenerability. Thus, the design and synthesis of targeted MOFs with appropriate pore size and increased interactions between organosulfur compounds and ligands/metals from MOFs is crucial for adsorptive desulfurization, which might be an effective guide to find an efficient and green adsorbent for desulfurization.
Diallyl disulfide (DADS) is a garlic-derived organosulfur compound. The current study is designed to evaluate the protective effects of DADS against ethanol-induced oxidative stress, and to explore the underlying mechanisms by examining the HO-1/Nrf-2 pathway.
Garlic contains the organosulfur compound allicin which exhibits potent antifungal activity. Here we demonstrate the use of a highly simplified yeast chemical genetic screen to characterize its mode of action. By screening 24 validated yeast gene deletion “signature” strains for which hypersensitivity is characteristic for common antifungal modes of action, yeast lacking the high affinity Cu2+ transporter Ctr1 was found to be hypersensitive to allicin. Focusing on transition metal related genes identified two more hypersensitive strains lacking the Cu2+ and Zn2+ transcription factors Mac1 and Zap1. Hypersensitivity in these strains was reversed by the addition of Cu2+ and Zn2+ ions respectively. The results suggest the antifungal activity of allicin is mediated through restricted Cu2+ and Zn2+ uptake or inhibition of Cu2+ and Zn2+ metalloproteins. As certain antimicrobial modes of action are much more common than others, the approach taken here provides a useful way to identify them early on.
We describe the synthesis, reactivity, and antithrombotic and anti-angiogenesis activity of difluoroallicin (S-(2-fluoroallyl) 2-fluoroprop-2-ene-1-sulfinothioate) and S-2-fluoro-2-propenyl-l-cysteine, both easily prepared from commercially available 3-chloro-2-fluoroprop-1-ene, as well as the synthesis of 1,2-bis(2-fluoroallyl)disulfane, 5-fluoro-3-(1-fluorovinyl)-3,4-dihydro-1,2-dithiin, trifluoroajoene ((E,Z)-1-(2-fluoro-3-((2-fluoroallyl)sulfinyl)prop-1-en-1-yl)-2-(2-fluoroallyl)disulfane), and a bis(2-fluoroallyl)polysulfane mixture. All tested organosulfur compounds demonstrated effective inhibition of either FGF or VEG-mediated angiogenesis (anti-angiogenesis activity) in the chick chorioallantoic membrane (CAM) or the mouse Matrigel® models. No embryo mortality was observed. Difluoroallicin demonstrated greater inhibition (p < 0.01) versus organosulfur compounds tested. Difluoroallicin demonstrated dose-dependent inhibition of angiogenesis in the mouse Matrigel® model, with maximal inhibition at 0.01 mg/implant. Allicin and difluoroallicin showed an effective antiplatelet effect in suppressing platelet aggregation compared to other organosulfur compounds tested. In platelet/fibrin clotting (anti-coagulant activity), difluoroallicin showed concentration-dependent inhibition of clot strength compared to allicin and the other organosulfur compounds tested.
On October 25, 2016, media reports alerted the Uganda Ministry of Health to an outbreak of >80 cases of vomiting, syncope, and acute diarrhea among workers at a flower farm in central Uganda; 27 workers were hospitalized. On November 1, an investigation was undertaken by the Uganda Public Health Fellowship Program.* A case-control study found that working inside greenhouse 7, which had been fumigated with the organosulfur compound metam sodium the night of October 13, was strongly associated with illness. Employees who worked in this greenhouse during October 14-21 reported a strong “suffocating” smell in the greenhouse. Investigation revealed that, in violation of safety protocols, workers did not properly cover the soil after fumigation, allowing vapors to become trapped inside the greenhouse. The farm management, unaware of the lapse, failed to inform workers to avoid the vicinity of the fumigation. Respiratory protective measures were not routinely available for workers, which likely contributed to the severity and extent of the outbreak. Although metam sodium is generally considered to be of low risk when used according to manufacturer’s instructions (1), occupational exposure in the absence of recommended safety measures can have serious health consequences. The investigation highlighted the importance of identifying potential occupational hazards to workers, as well as establishing safety protocols in occupational settings, training workers at risk, such as pesticide sprayers and flower pickers,† and ensuring enforcement of safety protocols. After this outbreak, the farm management reviewed, revised, and trained the workers on safety protocols to prevent future outbreaks.
Thiolactones have attracted considerable attention in recent years as bioactive natural products, lead compounds for drug discovery, molecular probes, and reagents for polymerisation. We have investigated radical-mediated C-C bond forming reactions as a strategy for thiolactone synthesis. Cyclisation of an α-bromo aluminium thioacetal was investigated under radical conditions. It was found that at low temperature, a radical fragmentation and rearrangement process occurs. A putative reaction mechanism involving a previously unreported aluminium templated thiol-ene step for the rearrangement process is presented. Cyclisation reactions of α-bromo thioesters and α-xanthate thioesters under radical mediated conditions furnished the desired thiolactones in moderate yields.
Cancer stem cells (CSCs) are responsible for colorectal cancer (CRC) initiation, growth, and metastasis. Garlic-derived organosulfur compound diallyl trisulfide (DATS) possesses cancer suppressive properties. Wnt/β-catenin signaling is a key target for CSCs inhibition. However, the interventional effect of DATS on colorectal CSCs has not been clarified. We aimed to illustrate the regulation of Wnt/β-catenin in DATS-induced colorectal CSCs inhibition.
Protective effect of methylallyl sulfone in the development of cigarette smoke extract-induced apoptosis in rats and HFL-1 cells
- Biochemical and biophysical research communications
- Published over 2 years ago
Although the organosulfur compounds from garlic have shown diverse pharmacological activities, the prototype drug was almost undetectable in vivo. As known, methylallyl sulfone (AMSO2) is the main metabolite of some active organosulfur compounds derived from garlic. The purpose of this article was to study the protective effect of AMSO2 on cigarette smoke extract (CSE) induced cell apoptosis in lungs in vivo and in vitro. The male rats were injected intraperitoneally with 900 μL of 100% CSE 3 times for three successive weeks. The rats from treatment groups were injected intraperitoneally with AMSO2 (50 mg/kg/day or 100 mg/kg/day) or DEX (1 mg/kg/day) for 21 days. We observed that pretreatment of AMSO2 effectively reversed apoptosis and oxidative stress in rats induced by CSE. Moreover, CSE-induced apoptosis in the HFL-1 cells was significantly suppressed by pretreated AMSO2 (400 μM) and DEX (0.1 mg/mL). Mechanistic studies suggested that this activity may arise from its effects on the regulation of p38 MAPK, Nrf-2 and Bcl-2/Bax signaling pathways. Overall, the metabolite of active organosulfur compounds AMSO2 might be a potential candidate for the treatment of CSE-induced apoptosis in rats.
Herein the synthesis of a novel and bench stable electrophilic reagent to construct the OCFHMe motif from O-nucleophiles has been described. This sulfonium salt, readily obtained in 5 steps, reacted with various phenols and alcohols. The resulting products, including complex molecules, were obtained in good yields. This reagent was also used for the functionalization of thiol derivatives.