Se Bond Formation Research Articles

Microfluidic sensor integrated with selenite-enriched lanthanum hydroxide and in situ filtration for the on-site detection of the antibiotic trimethoprim in environmental samples

The improper disposal of antibiotics in water bodies and using contaminated wastewater in irrigation severely damage the environment. Despite efforts to monitor these contaminants, effective detection methods are limited. Here, we design and develop a novel microfluidic electrochemical (EC) sensor for on-site detection of trimethoprim (TMP) using a selenite-enriched lanthanum hydroxide (La(OH)3:SeOx) working electrode and a polyimide (PI)-filter integrated microfluidic channel (MFC), thus termed a “µTMP-chip”. For the first time, we introduced a new two-pronged strategy for enhancing TMP detection: i) incorporating selenite into the La(OH)3 lattice to improve charge transfer properties and ii) using a laser-processed PI filter in the MFC to trap and isolate complex biomasses. Material characterizations confirmed that incorporating selenite into the La(OH)3 lattice initiated La–O–Se bond formation and enhanced hybridization between the La 4f and O 2p orbitals. This process created holes in the O 2p valence band and improved the charge transfer properties, thus enhancing both sensitivity and selectivity. EC studies confirmed that when the PI filter is not used in the MFC, the µTMP-chip experiences a 15–45 % drop in efficiency. The scalable µTMP-chip offers cost-effective, highly reproducible TMP detection in soil and water.

Visible Light Induced Photocatalyst‐Free C−X (X=B, C, O, P,S, Se) Bond Formation of Aryl Halides

AbstractAryl halides are one of the most important chemical feedstocks in pharmaceuticals due to its easy accessibility, inexpensiveness, and widely utilized as aryl radical precursors in organic synthetic chemistry. Conventionally, the stoichiometric reagents such as AIBN/n‐Bu3SnH were used for generation of aryl radical from aryl halides, and suffered from requirement of toxic radical initiators, high temperature and thus, the development of simple, mild strategies for the generation of aryl radical from aryl halides are highly desirable. Recently, visible light mediated strategies received considerable attention, allowing the generation of aryl radical from aryl halides under mild reaction conditions. The present review described the recent breakthroughs and advancements in visible light mediated photocatalyst‐free C−B/C/O/P/Se/S bond formation of aryl halides.

Enzymatic synthesis of organoselenium compounds via C‒Se bond formation mediated by sulfur carrier proteins

Enzymatic synthesis of organoselenium compounds via C‒Se bond formation mediated by sulfur carrier proteins

Silver Natural Asphalt Sulfonate (NA-SO3Ag): Fabrication and Utilization as a New Heterogeneous, Carbonaceous, and Retrievable Nanocatalyst for C(sp2)-X (X = C, S, and Se) Bond Formation.

Silver-based catalysts are valuable catalysts in various areas of the chemical industry, organic syntheses, and transformations, and from a chemical and industrial point of view, their recycling is very important. Herein, silver natural asphalt sulfonate (NA-SO3Ag) was fabricated via the grafting of Ag(I) on the surface of the solid natural asphalt sulfonate as a novel and efficient recoverable sliver nanocatalyst. Natural asphalt is one of the hydrocarbons that are found in mineral veins. The structure of NA-SO3Ag was characterized by diverse microscopic and spectroscopic techniques including Fourier-transform infrared (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), thermogravimetric analysis (TGA), Brunauer-Emmett-Teller (BET), X-ray diffraction (XRD), and inductively coupled plasma optical emission spectroscopy (ICP-OES) techniques. The NA-SO3Ag nanocatalyst was utilized for C-Se and C-S bond formation via coupling reactions of aryl halides and organic disulfides/diselenides to afford a wide variety of diaryl sulfides/selenides in good to excellent yields. Additionally, the utilization of NA-SO3Ag in C-C bond formation was examined in Suzuki coupling reactions successfully. For at least 6 trials, this heterogeneous catalyst can be separated and reused without any activity reduction.

Antibacterial Activity of Ebselen.

Ebselen is a low-molecular-weight organoselenium compound that has been broadly studied for its antioxidant, anti-inflammatory, and cytoprotective properties. These advantageous properties were initially associated with mimicking the activity of selenoprotein glutathione peroxidase, but the biomedical impact of this compound appear to be far more complex. Ebselen serves as a substrate or inhibitor with multiple protein/enzyme targets, whereas inhibition typically originates from the covalent modification of cysteine residues by opening the benzisoselenazolone ring and S-Se bond formation. The inhibition of enzymes of various classes and origins has been associated with substantial antimicrobial potential among other activities. In this contribution, we summarize the current state of the art regarding the antibacterial activity of ebselen. This activity, alone and in combination with commercial pharmaceuticals, against pathogens, including those resistant to drugs, is presented, together with the molecular mechanism behind the reactivity. The specific inactivation of thioredoxin reductase, bacterial toxins, and other resistance factors is considered to have certain therapeutic implications. Synergistic action and sensitization to common antibiotics assisted with the use of ebselen appear to be promising directions in the treatment of persistent infections.

Metal and Metal Oxide Nanoparticles Catalyzed C–H Activation for C–O and C–X (X = Halogen, B, P, S, Se) Bond Formation

The direct functionalization of an inactivated C–H bond has become an attractive approach to evolve toward step-economy, atom-efficient and environmentally sustainable processes. In this regard, the design and preparation of highly active metal nanoparticles as efficient catalysts for C–H bond activation under mild reaction conditions still continue to be investigated. This review focuses on the functionalization of un-activated C(sp3)–H, C(sp2)–H and C(sp)–H bonds exploiting metal and metal oxide nanoparticles C–H activation for C–O and C–X (X = Halogen, B, P, S, Se) bond formation, resulting in more sustainable access to industrial production.

Synthesis of novel alkynyl imidazopyridinyl selenides: copper-catalyzed tandem selenation of selenium with 2-arylimidazo[1,2-a]pyridines and terminal alkynes.

Alkynyl selenides have attracted considerable research interest recently, owing to their applications in the biological and pharmaceutical fields. The Cu-catalyzed tandem reaction for the synthesis of novel alkynyl imidazopyridinyl selenides is presented. A one-pot synthesis route afforded alkynyl imidazopyridinyl selenides in moderate to good yields. This was achieved by a two-step reaction between terminal alkynes and diimidazopyridinyl diselenides, generated from imidazo[1,2-a]pyridines and Se powder, using 10 mol % of CuI and 1,10-phenanthroline as the catalytic system under aerobic conditions. The C(sp2)–Se and C(sp)–Se bond-formation reaction can be performed in one-pot by using inexpensive and easy to handle Se powder as the Se source. The reaction proceeded with terminal alkynes having various substitutions, such as aryl, vinyl, and alkyl groups. The obtained alkynyl imidazopyridinyl selenide was found to undergo nucleophilic substitution reaction on Se atom using organolithium reagents and 1,3-dipolar azide–alkyne cycloaddition based on the alkyne moiety.

Room Temperature, Metal-Free, Regioselective Arylselenation of Anilines Using Diselenides as Selenium Source

AbstractA metal-free direct C–H selenation of aniline derivatives via an iodine-catalyzed C–Se bond formation using diselenides as a selenium source at ambient temperature is described. A variety of aniline derivatives underwent regioselective C–H selenation with different diselenides to afford the corresponding aryl selenoethers in good to excellent yields.

Magnetic mesocellular foams with nickel complexes: as efficient and reusable nanocatalysts for the synthesis of symmetrical and asymmetrical diaryl chalcogenides.

In this work, magnetic mesocellular foam (M-MCF) silica nanoparticles were prepared via inserting magnetic nanoparticles into the pores of mesocellular foams, the inner surface of which was functionalized with a methionine–nickel complex (M-MCF@Met–Ni). The structure of the as-prepared nanocatalysts was studied by FT-IR spectroscopy, BET, TGA, VSM, SEM, HR-TEM, EDS, WDX, XRD, and ICP-OES techniques. Thereafter, this nanocatalyst was used as a new, effective, and magnetically reusable catalyst for C–S and C–Se bond formation under mild conditions. All corresponding products were prepared with good yields and appropriate turnover number (TON) and turnover frequency (TOF), which reveals the high activity of this magnetic nanocatalyst in both reactions. In addition, the recovery and hot filtration tests indicated that this catalyst could be simply separated from the reaction mixture using an outside magnet and reused five consecutive times without any significant loss of its catalyst activity or metal leaching.

Generation of I-, ArS- and ArSe- substituted pyrrolo[3,4–c]pyridine derivatives using copper iodide as an iodinating agent

A new, efficient and operationally simple copper mediated C−I, CS and C−Se bond formation protocol has been developed. This process proceeds smoothly under mild aerobic condition to give CH iodinated, sulfenylated and selenenylated pyrrolo[3,4–c]pyridines derivative. The versatility of this process has been successfully established by simply varying different electrophile. This copper iodide-mediated CH functionalization approach provides a direct access of structurally diverse 7-iodinated/sulfenylated/selenenylated pyrrolo[3,4–c]pyridine derivatives in good to excellent yield within short reaction time.

Organometallic reagents primed for peptide modification

In this issue of Chem Catalysis , Walczak and co-workers introduce a carbastannatrane alanine derivative that facilitates amino acid side-chain functionalizations via C–C, C–S, and C–Se bond formation using Stille cross-coupling reactions. Applications in late-stage peptide modifications and macrocyclizations further exemplify the value of this novel building block. In this issue of Chem Catalysis , Walczak and co-workers introduce a carbastannatrane alanine derivative that facilitates amino acid side-chain functionalizations via C–C, C–S, and C–Se bond formation using Stille cross-coupling reactions. Applications in late-stage peptide modifications and macrocyclizations further exemplify the value of this novel building block.

Forging C−S(Se) Bonds by Nickel‐catalyzed Decarbonylation of Carboxylic Acid and Cleavage of Aryl Dichalcogenides

AbstractA nickel‐catalyzed decarbonylation of carboxylic acids cross‐coupling protocol has been developed for the straightforward C−S(Se) bond formation. This reaction is promoted by a commercially‐available, user‐friendly, inexpensive, air and moisture‐stable nickel precatalyst. Various carboxylic acids and a wide range of aryl dichalcogenide substrates were tolerated in this process which afforded products in good to excellent yields. In addition, the present reaction can be conducted on gram scale in good yield.

Iron-catalyzed cascade reaction of C(sp3)-Se bond cross-coupling/C-N bond formation.

An iron-catalyzed cascade reaction of C(sp3)-Se bond cross-coupling/C-N bond formation was developed. Various 5,13a-dihydro-6H,8H-benzo[5,6][1,3]selenazino[2,3-a]isoquinolin-8-one derivatives were synthesized under mild conditions starting from 1,2,3,4-tetrahydroisoquinolines and 2-hydroselenobenzoic acids. This protocol provides an economical approach for C(sp3)-Se bond formation.

Copper-catalyzed domino synthesis of benzo[d]imidazo[5,1-b][1,3]selenazoles involving sequential intermolecular cycloaddition and intramolecular Ullmann-type C–Se bond formation

A copper-catalyzed domino synthesis of benzo[d]imidazo[5,1-b][1,3]selenazoles involving sequential intermolecular cycloaddition and intramolecular Ullmann-type C–Se bond formation has been developed.

The hetero-Friedel-Crafts-Bradsher Cyclizations with Formation of Ring Carbon-Heteroatom (P, S) Bonds, Leading to Organic Functional Materials.

The interest in functional materials possessing improved properties led to development of new methods of their synthesis, which allowed to obtain new molecular arrangements with carbon and heteroatom motifs. Two of the classical reactions of versatile use are the Friedel-Crafts and the Bradsher reactions, which in the new heteroatomic versions allow to replace ring carbon atoms by heteroatoms. In the present work, we review methods of synthesis of C–S and C–P bonds utilizing thia- and phospha-Friedel-Crafts-Bradsher cyclizations. Single examples of C–As and lack of C–Se bond formation, involving two of the closest neighbors of P and S in the periodic table, have also been noted. Applications of the obtained π-conjugated molecules, mainly as semiconducting materials, flame retardants, and resins hardeners, designed on the basis of five- and six-membered cyclic molecules containing ring phosphorus and sulfur atoms, are also included. This comprehensive review covers literature up to August 2020.

Creation of 4-Quinolone Thioether and Selenoether Derivatives via Pd-NHC Catalysed Cross-Coupling Reaction

Pd-NHC catalysed direct sulfenylation and selenylation of 3-iodo-4-quinolones has been developed. This protocol provides an alternative route for the construction of ipso-C–S and C–Se bond formation in 4-quinolones under aerobic conditions.

Rhodium‐Catalyzed Synthesis of Heteroarylselenyl Esters from Diheteroaryl Diselenides and Acid Fluorides

AbstractA rhodium complex catalyzed C−Se bond formation between diheteroaryl diselenides and acid fluorides in the presence of triphenylphosphine to provide heteroarylselenyl esters in good yields. The reaction was applicable to five‐ and six‐membered heteroaryl compounds. The heteroarylselenyl esters can be used as heteroaryselenating reagents in the synthesis of heteroaryl selenides, as shown by a platinum‐catalyzed addition reaction with 1‐octyne.

K2S2O8-promoted C-Se bond formation to construct α-phenylseleno carbonyl compounds and α,β-unsaturated carbonyl compounds.

A novel K2S2O8-promoted C–Se bond formation from cross-coupling under neutral conditions has been developed. A variety of aldehydes and ketones react well using K2S2O8 as the oxidant in the absence of catalyst and afford desired products in moderate to excellent yields. This protocol provides a very simple route for the synthesis of α-phenylseleno carbonyl compounds and α,β-unsaturated carbonyl compounds.

Iron-catalyzed tandem reaction of C-Se bond coupling/selenosulfonation of indols with benzeneselenols.

An iron-catalyzed tandem reaction of C–Se bond coupling/selenosulfonation was developed. Starting from sample indols and benzeneselenols versatile biologically active 2-benzeneselenonyl-1H-indoles derivatives were efficiently synthesized. The reaction mechanism was studied by the deuterium isotope study and in situ ESI-MS experiments. This protocol features mild reaction conditions, wider substrate scope and provides an economical approach toward C(sp2)–Se bond formation.

Nickel-Catalyzed Thiolation and Selenylation of Cycloketone Oxime Esters with Thiosulfonate or Seleniumsulfonate.

A nickel-catalyzed ring opening and, subsequently, reductive cross-coupling of cycloketone oxime esters with thiosulfonate or seleniumsulfonate are reported, which involves C-C bond cleavage and C(sp3)-S or C(sp3)-Se bond formation. Notably, S-aryl/alkyl sulfonothioates and Se-alkyl seleniumsulfonothioates could be employed in this reaction to afford a variety of 1° and 2° alkyl sulfides, aryl sulfides, and 1° and 2° alkyl selenides in one step. This strategy features easily available substrates and mild reaction conditions.