Diorganyl Dichalcogenides Research Articles

Electricity-driven, oxidative C-H selenylative and tellurylative annulation of N-(2-alkynyl)anilines: sustainable synthesis of 3-selanyl/tellanylquinolines.

A metal- and oxidant-free, radical C-H selenylative and tellurylative annulation of N-(2-alkynyl)anilines with diorganyl dichalcogenides is developed under electrochemical conditions for the sustainable synthesis of valuable 3-selanyl/tellanylquinolines up to 92% yield at room temperature. The developed protocol required only electricity as the green reagent and offers high atom economy, broad substrate scope, and efficient scalability.

Advances in Difunctionalization of Olefins with Diorganyl Dichalcogenides.

Organochalcogen molecules have extensive applications in various fields. They serve as pharmaceuticals, ligands, organocatalysts, agrochemicals, and other functional materials. Difunctionalization of olefins, which belong to a class of multicomponent reactions, is a successful technique for introducing two functional moieties in a single-step reaction, both in terms of atom economy and step economy. The difunctionalization of olefins with diorganyl dichalcogenides may effectively increase the molecular complexity, which has achieved significant advancements in recent decades. This article describes recent advancements in the difunctionalization of olefins with diorganyl diselenides and diorganyl disulfides.

Synthesis of 3-chalcogenyl-indoles mediated by the safer reagent urea-hydrogen peroxide (UHP)

Herein, we report the use of urea-hydrogen peroxide (UHP) as an oxidizing agent in the direct C3 chalcogenylation of indoles with diorganyl dichalcogenides, in the presence of an iodine source. This reagent provided a simple, efficient and safer reaction media, besides avoid problems related to the aqueous solutions oxidants. This method allowed the preparation of 20 compounds in good to excellent yields, being efficient also in large scale.

Cu-catalysed Chan–Lam synthesis of unsymmetrical aryl chalcogenides under aqueous micellar conditions

Herein, we report a green and sustainable Cu-catalysed Chan–Lam oxidative protocol for the synthesis of (hetero)aryl selenides/sulfides from diorganyl dichalcogenides and (hetero)aryl boronic acids in an aqueous micellar medium.

One‐pot Sequential Strategy to Prepare Organoselanyl and Organotellanyl Isoquinolinium Imides

AbstractHerein, we report an efficient, transition‐metal‐free and practical one‐pot sequential method for the synthesis of organochalcogenyl isoquinolinium imides. In this one‐pot two‐steps approach, N′‐(2‐alkynylbenzylidene) hydrazides were firstly prepared under ultrasound irradiation, followed by the addition of diorganyl dichalcogenides and Oxone®. A total of 25 organoselanyl isoquinolinium imides, being 22 unprecedented in the literature, were obtained in good to excellent yields (79–95 %) in short reaction times (30–70 min) using a range of 2‐alkynyl aldehydes and diaryl, dialkyl, and diheteroaryl diselenides as substrates. The methodology was extended to tellurium, affording for the first time, tellurium isoquinolinium imides, in good yields (70–80 %) after 120 min of reaction.

Trichloroisocyanuric Acid‐Promoted Synthesis of Arylselenides and Aryltellurides from Diorganyl Dichalcogenides and Arylboronic Acids at Ambient Temperature

AbstractA transition‐metal‐free method for the synthesis of arylselenides and aryltellurides has been established based on the oxidative cross‐coupling between diorganyl dichalcogenides and aryl boronic acids. With trichloroisocyanuric acid as an oxidant, the reaction proceeded smoothly to afford the desired products in 45–97% yields at ambient temperature. Three reaction reagents used in this method are stoichiometric and the oxidation by‐product isocyanuric acid can be easily isolated and recovered. Besides of arylboronic acids, aryl trifluoroborates and aryl trihydroxyborates salts are also able to perform this transformation.magnified image

Cooperative action between Iron(III) chloride and diorganyl dichalcogenides for the cyclization of N-(ortho-Alkynyl)aryl-pyrroles

We report the ability of iron(III) chloride and diorganyl dichalcogenides to promote de cyclization of N -( ortho -alkynyl)aryl-pyrroles leading to 5-(organochalcogenyl)pyrrolo[1,2- a ]quinolines. The combination of diorganyl dichalcogenides and iron(III) chloride was crucial for the cyclization reaction to occur because neither the iron salt nor diorganyl diselenide alone were able to promote the cyclization. The effects of solvent, temperature, reaction time, and stoichiometry on the efficiency of cyclization reactions were investigated. The standard reaction conditions were compatible with many functional groups in the substrates, such as methyl, chlorine, and methoxy. In addition, under these conditions, not only diaryl, but also dialkyl dichalcogenides have been cyclized in moderate to good yields. The 5-(organochalcogenyl)pyrrolo[1,2- a ]quinolines prepared underwent a Suzuki cross-coupling reaction with boronic acids under palladium catalyze to give the cross-coupled products in good yields.

Diorganyl Dichalcogenides and Copper/Iron Salts: Versatile Cyclization System To Achieve Carbo- and Heterocycles from Alkynes

AbstractOrganochalcogen-containing cyclic molecules have shown several promising pharmacological properties. Consequently, different strategies have been developed for their synthesis in the past few years. Particularly due to the low cost and environmental aspects, copper- and iron-promoted cyclization reactions of alkynyl substrates have been broadly and efficiently applied for this purpose. This short review presents an overview of the most recent advances in the synthesis of organochalcogen-containing carbo- and heterocycles by reacting diorganyl disulfides, diselenides, and ditellurides with alkyne derivatives in the presence of copper and iron salts to promote cyclization reactions.1 Introduction2 Synthesis of Carbo- and Heterocycles via Reactions of Alkynes with Diorganyl Dichalcogenides and Copper Salts3 Synthesis of Carbo- and Heterocycles via Reactions of Alkynes with Diorganyl Dichalcogenides and Iron Salts4 Conclusions

Base-Free Synthesis and Synthetic Applications of Novel 3-(Organochalcogenyl)prop-2-yn-1-yl Esters: Promising Anticancer Agents

AbstractThis manuscript portrays the CuI-catalyzed Csp-chalcogen bond formation through cross-coupling reactions of propynyl esters and diorganyl dichalcogenides by using DMSO as solvent, at room temperature, under base-free and open-to-air atmosphere conditions. Generally, the reactions have proceeded very smoothly, being tolerant to a range of substituents present in both substrates, affording the novel 3-(organochalcogenyl)prop-2-yn-1-yl esters in moderate to good yields. Noteworthy, the 3-(butylselanyl)prop-2-yn-1-yl benzoate proved to be useful as synthetic precursor in palladium-catalyzed Suzuki and Sonogashira­ type cross-coupling reactions by replacing the carbon–chalcogen bond by new carbon–carbon bond. Moreover, the 3-(phenyl­selanyl)prop-2-yn-1-yl benzoate has shown promising in vitro activity against glioblastoma cancer cells.

Synthesis of 2‐Aryl‐(3‐Organochalcogenyl)Thieno[2,3‐b]Pyridines Promoted by Oxone®

AbstractWe describe herein an alternative method for the synthesis of 2‐aryl‐(3‐organochalcogenyl)thieno[2,3‐b]pyridines through the electrophilic cyclization of 3‐(arylethynyl)‐2‐(alkylthio)pyridines promoted by electrophilic species of organochalcogen compounds. These species were generated in situ by the oxidative cleavage of chalcogen‐chalcogen (Se, Te) bond of diorganyl dichalcogenides using Oxone® in ethanol as solvent in an open‐flask at 78 °C. The protocol allowed the synthesis of highly substituted thieno[2,3‐b]pyridines starting from several diorganyl dichalcogenides and 3‐(arylethynyl)‐2‐(alkylthio)pyridines, obtaining 21 new compounds in good to excellent yields (70–99%). Still, the method showed good efficiency on the gram‐scale synthesis. In addition, several synthetic transformations such as oxidation, selenylation and hydrogenation reactions were demonstrated.

Synthesis of 4-Selanyl- and 4-Tellanyl-1H-isochromen-1-ones Promoted by Diorganyl Dichalcogenides and Oxone

A new method was developed for the synthesis of 4-chalcogenyl-1H-isochromen-1-ones through the 6-endo-dig electrophilic cyclization of 2-alkynylaryl esters and diorganyl dichalcogenides under ultrasound irradiation. The reactions were performed under mild conditions, using Oxone as a green oxidant to promote the cleavage of the chalcogen-chalcogen bond in diorganyl diselenides and ditellurides to generate electrophilic species in situ. A total of 25 compounds were selectively obtained after 30-70 min, in good to excellent yields (74-95%). This procedure was extended to prepare 5H-selenopheno[3,2-c]isochromen-5-ones. Additionally, for the first time, the 4-chalcogenyl-1H-isochromen-1-ones were used as substrates in the thionation reaction, using Lawesson's reagent and microwave irradiation under solvent-free conditions, obtaining the thio derivatives in yields of up to 99% in only 15 min.

Oxone-Promoted Synthesis of 4-(Chalcogenyl)isoquinoline-N-oxides from Alkynylbenzaldoximes and Diorganyl Dichalcogenides.

We report a protocol for the synthesis of 3-organyl-4-(organylchalcogenyl)isoquinoline-2-oxides via electrophilic cyclization between alkynylbenzaldoximes and diorganyl dichalcogenides promoted by Oxone. A total of 21 3-organyl-4-(organylchalcogenyl)isoquinoline-2-oxides were selectively obtained in yields of up 93% under an ultrasound irradiation condition in short reaction times (10-70 min). Additionally, the synthetic usefulness of the 3-phenyl-4-(phenylselanyl)isoquinoline-2-oxide was demonstrated in the annulation reaction with 1-(2-bromophenyl)-3-phenylprop-2-yn-1-one and in the deoxygenation reaction with phenylboronic acid.

Diorganyl Diselenides and Iron(III) Chloride Drive the Regio- and Stereoselectivity in the Selenation of Ynamides.

We report here our results on the application of ynamides as substrates in the reactions with diorganyl dichalcogenides and iron(III) chloride to give selectively three different types of compounds: E-α-chloro-β-(organoselenyl)enamides, 4-(organochalcogenyl)oxazolones, and vinyl tosylates. The results reveal that the selectivity in the formation of products was obtained by controlling the functional groups directly bonded to the nitrogen atom of the ynamides. Thus, α-chloro-β-(organoselenyl) enamide derivatives were exclusively obtained when the TsN- and MsN-ynamides were treated with a mixture of diorganyl diselenides (1.0 equiv) and FeCl3 (3.0 equiv) in dichloroethane (DCE, 3 mL), at room temperature. The 4-(organochalcogenyl)oxazolones were selectively obtained with ynamides having an ester group, directly bonded to the nitrogen atom, upon treatment with a solution of FeCl3 (1.5 equiv) and diorganyl dichalcogenides (1.0 equiv) in dichloromethane (3 mL) at room temperature. Finally, vinyl tosylates were obtained from ynamides having an ester group, directly bonded to the nitrogen atom, by reaction with p-toluenesulfonic acid. We also studied the application of the prepared compounds as substrates for Suzuki and Sonogashira cross-coupling reactions.

A greener protocol for the synthesis of phosphorochalcogenoates: Antioxidant and free radical scavenging activities.

In this contribution, a metal- and base-free protocol has been developed for the synthesis of phosphorochalcogenoates (Se and Te) by using DMSO as solvent at 50°C. A variety of phosphorochalcogenoates were prepared from diorganyl dichalcogenides and H-phosphonates, leading to the formation of a Chal-P(O) bond, in a rapid procedure with good to excellent yields. A full structural elucidation of products was accessed by 1D and 2D NMR, IR, CGMS, and HRMS analyses, and a stability evaluation of the phosphorochalcogenoates was performed for an effective operational description of this simple and feasible method. Typical 77Se{1H} (δSe=866.0ppm), 125Te{1H} (δTe=422.0ppm) and 31P{1H} (δP=-1.0,-13.0 and-15.0ppm) NMR chemical shifts were imperative to confirm the byproducts, in which this stability study was also important to select some products for pharmacological screening. The phosphorochalcogenoates were screened invitro and exvivo tests for the antioxidant potential and free radical scavenging activity, as well as to investigation toxicity in mice through of the plasma levels of markers of renal and hepatic damage. The pharmacological screening of phosphorochalcogenoates indicated that compounds have antioxidant propriety in different assays and not changes plasma levels of markers of renal and hepatic damage, with excision of 3g compound that increased plasma creatinine levels and decreased plasma urea levels when compared to control group in the blood mice. Thus, these compounds can be promising synthetic antioxidants that provide protection against oxidative diseases.

Diorganyl Dichalcogenides as Surface Capping Ligands for Germanium Nanocrystals

Indirect ligand exchange methods have been demonstrated to replace the oleylamine capping with dodecanethiol for germanium nanocrystals (Ge NCs). In these methods, hydrazine is employed to effectiv...

Copper-catalyzed Csp-chalcogen bond formation: Versatile approach to N-(3-(organochalcogenyl)prop-2-yn-1-yl)amides

This work describes the copper-catalyzed Csp-chalcogen bond formation through cross-coupling reactions of propynylbenzamides and diorganyl dichalcogenides at room temperature, under open atmosphere. Generally, the reactions have proceeded very smoothly, affording the new class of organochalcogen-containing propynylbenzamides in good yields. Notably, this protocol showed to be tolerant to neutral, electron-donating and electron-withdrawing substituents present in both reaction substrates. In addition, the applicability of the carbon-chalcogen bond as a reactive site has been proved by successfully employment of the N-methyl-N-(3-(butylselanyl)prop-2-yn-1-yl)benzamide as a precursor in palladium-catalyzed Suzuki and Sonogashira type reactions.

Alternative Metal-Free Synthesis of Diorganoyl Selenides and Tellurides Mediated by Oxone®

We herein describe an alternative metal-free methodology for the synthesis of diorganyl selenides and tellurides mediated by ­Oxone®. The products were obtained in moderate to excellent yields by reactions of diorganyl diselenides or ditellurides with aryl boronic acids mediated by Oxone® with use of EtOH as the solvent. The methodology is applicable to a broad scope of diorganyl dichalcogenides and aryl boronic acids containing electron-rich, electron-poor, and sterically hindered substituents.

Fe3O4 Nanoparticles: A Robust and Magnetically Recoverable Catalyst for Direct C‐H Bond Selenylation and Sulfenylation of Benzothiazoles

AbstractHerein, we report the magnetically recoverable Fe3O4 nanoparticle‐catalyzed synthesis of 2‐organochalcogen‐benzothiazoles via direct C−H bond chalcogenation. This new approach works under an air atmosphere, affording the desired products in good to excellent yields using benzothiazoles, a half‐molar equiv. of various diorganyl dichalcogenides, and 10 mol % of catalytic loading. The method is attractive due to the recyclability of the catalyst and tolerance of a wide range of functional groups.

Ammonium iodide-mediated regioselective chalcogenation of chromones with diaryl disulfides and diselenides

ABSTRACTA metal-free method for the synthesis of 3-chalcogenyl-chromones/quinolones from chromones/quinolones and diorganyl dichalcogenides using ammonium iodide under air was developed. This approach allowed the preparation of a wide range of 3-selenyl- and 3-sulfenyl-chromones/quinolones in good to excellent yields.

Synthesis of enantiomerically pure glycerol derivatives containing an organochalcogen unit: In vitro and in vivo antioxidant activity

We describe here the synthesis of enantiomerically pure chalcogenoethers obtained through the reaction of nucleophilic species of chalcogen (S, Se and Te), generated in situ from the respective diorganyl dichalcogenides, with (R)- and (S)-tosyl solketal. Furthermore, some of the chalcogenoethers were treated with acidic cation exchange resin Dowex-(H+) leading to the respective deprotected enantiomerically pure 3-phenylchalcogenyl-1,2-diols. In order to explore the biological potential of these molecules, the antioxidant activity of some organochalcogens was evaluated by several in vitro assays. Overall, the chalcogenoethers containing Te were better scavengers of DPPH and ABTS+ radicals, had higher ferric reducing capacity and prevented lipid peroxidation. To analyze the effects of these compounds in vivo, we used the alternative model Caenorhabditis elegans. Chalcogenoethers treatment, especially (S)- and (R)-2,2-dimethyl-4-(phenylselanylmethyl)-1,3-dioxolane, conferred protection against the mortality-induced by hydrogen peroxide. Accordingly, these chalcogenoethers were able to modulate the antioxidant enzyme catalase. Notably, the compounds did not present toxicity in worm’s reproduction. To sum up, our study demonstrated that Te- containing chalcogenoethers were promising in vitro scavengers, while Se molecules were more prone to protect against a stressor in vivo. In this sense, the antioxidant activity of chalcogenoethers, especially with Se and Te, indicates that these molecules may have biological application in an attempt to reduce the oxidative stress.