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We report herein a visible light sensitizer-catalyzed aerobic oxidation of thioethers, affording sulfoxides in good to excellent yields. The loading of the catalyst was as low as 0.1 mol%. The selectivity was excellent. Mechanism studies showed both singlet oxygen and superoxide radical anion were likely involved in this transformation.

Although many chiral ligands for asymmetric catalysis have been developed, there is still a need for new structures allowing the modular approach. Recently, easy synthesis of chiral pyridine-containing β-amino alcohols has been elaborated by opening respective epoxides with enantiomeric 1-phenylethylamine. This paper reports the synthetic transformation of β-amino alcohols into the new complexing pyridine-containing seleno- and thioethers. The amino alcohols were effectively converted to cyclic sulfonamidates, which were reacted with thiolates or phenyl selenide nucleophile. The reaction was diastereoselective, and its outcome depended on the configuration at the substitution center. The problem was discussed considering DFT optimized structures of both diastereomeric sulfonamidates. New amino-aldimine ligands were also synthesized from chiral pyridine-containing diamines. Nine new chiral ligands were tested in the Tsuji-Trost allylic alkylation resulting in the enantiomerically enriched product in up to 75% ee. The observed stereochemical induction agrees with the prevailing nucleophilic attack at the allylic carbon laying opposite to the complexing nitrogen of pyridine in η3-allylic intermediate complexes.

A novel approach for the synthesis of 1,3,4-oxa(thia)diazole aryl thioethers through a biocatalytic strategy has been introduced. By leveraging Myceliophthora thermophila laccase (Novozym 51003) as a catalyst, catechol undergoes oxidation to ortho-quinone, facilitating subsequent 1,4-thia-Michael addition reactions. The method offers efficiency and mild reaction conditions, demonstrating promise for sustainable synthesis pathways in organic chemistry. Using this approach, 13 new derivatives of 2,5-disubstituted-1,3,4-oxa(thia)diazole aryl thioethers, with a yield of 46–94%, were synthesized.

C(sp 3 )−H activation and functionalization of unactivated hydrocarbons has provided enormous opportunities for the construction of diverse organic molecules, which facilitates the structural modification of pharmaceutical molecules. To achieve this goal, the direct hydrogen atom transfer (HAT) via radical pathway has become an attractive strategy. Taking the advantage of photo/electrochemistry, we herein describe oxidative C(sp 3 )−H amination and etherification reactions via a photoelectrochemical pathway, which could directly transform easily available hydrocarbons into N -heterocycle and ether products under mild conditions. Applying 9-phenylacridine as a direct hydrogen atom transfer (d-HAT) reagent under 390 nm LED light irradiation and electrolysis, the scope of our method includes not only simple alkanes, but also a wide range of C(sp 3 )−H molecules including ethers, thioethers, silanes, and amides. The reaction shows broad scope (>135 examples) and unconventional regioselectivity, with the occurrence of both C(sp 3 )−H amination and etherification preferentially at the sterically unhindered positions. Furthermore, gram-scale experiments and relevant mechanistic investigations are carried out to illustrate the reaction mechanism. Here the authors describe oxidative C(sp3)−H amination and etherification reactions via a photoelectrochemical pathway, which directly transforms easily available hydrocarbons into N-heterocycle and ether products under mild conditions.

Most surfaces are either static or switchable only between “on” and “off” states for a specific application. It is a challenge to develop reconfigurable surfaces that can adapt to rapidly changing environments or applications. Here, we demonstrate fabrication of surfaces that can be reconfigured for user-defined functions using visible-light-controlled Ru–thioether coordination chemistry. We modify substrates with Ru complex Ru-H 2 O. To endow a Ru-H 2 O-modified substrate with a certain function, a functional thioether ligand is immobilized on the substrate via Ru–thioether coordination. To change the surface function, the immobilized thioether ligand is cleaved from the substrate by visible-light-induced ligand dissociation, and then another thioether ligand with a distinct function is immobilized on the substrate. Different thioethers endow the surface with different functions. Based on this strategy, we rewrite surface patterns, manipulate protein adsorption, and control surface wettability. This strategy enables the fabrication of reconfigurable surfaces with customizable functions on demand. Configuring surfaces on-demand for desired functionalities is an ongoing challenge. Here, diverse and tailorable modifications of quartz and porous silica surfaces that are rapidly and reversibly switchable by the use of visible light are achieved via ruthenium-thioether coordination.

A metal-free dehydrative thioetherification method has been reported, enabling the conversion of various alcohols and thiols into thioethers. By employing triflic acid as a catalyst or utilizing a recyclable NAFION® superacid catalyst, these methods significantly improve the efficiency and practicality of sulfide preparation.

A new series of thioethers containing a 1,2,4-oxadiazole ring were synthesized by the modified Riemschneider reaction. The corresponding thiocyanate derivatives of 1,2,4-oxadiazoles were obtained in good yields by the reaction of 3-aryl-5-chloromethyl-1,2,4-oxadiazole compounds with NH 4 SCN in triethylene glycol at 60 °C as a new method. Thioether derivatives were synthesized by reacting 5-thiocyanato-3-aryl-1,2,4-oxadiazole with various tertiary or secondary alcohols in solvent-free conditions for 10–30 min at 60 °C. The synthesized compounds were characterized by various spectroscopic methods (FTIR, 1 H NMR, 13 C NMR, and HRMS). All 1,2,4-oxadiazole-thioethers were tested for xanthine oxidase (XO), acetylcholinesterase (AChE), and butyrylcholinesterase (BChE) inhibition potential. The results showed that 4 h has more potential inhibition activity than positive control for XO (IC 50  = 0.41 ± 0.067 µM) and AChE/BChE (IC 50  = 0.95 ± 0.42 µM/1.49 ± 0.45 µM) and is considerably greater than other compounds. Moreover, our experimental study was supported by molecular docking to describe the binding mode of new structures to enzymes. The molecular docking calculations showed that molecules with high binding energy with at least one enzyme were 4b, 4d, 4g, 4h, 4i, 4j, 4k, and 4l. The physicochemical, ADMET, and drug-likeness parameters were computed using the SwissADMET online program. In silico studies of the molecules demonstrated that five molecules, 4b, 4d, 4g, 4h, and 4l, had relatively optimum drug similarity and medicinal chemistry properties. The five molecules synthesized and characterized in this study can be further investigated as drug or drug-like compound candidates.

A series of new RS−, RS−CH 2 − and R 2 N−CH 2 -functionalized сatechols with heterocyclic fragments such as 1,3,4-oxadiazole, 1,2,4-triazole, thiazole, or pyridine were synthesized by the reaction of 3,5-di- tert -butyl- o -benzoquinone or 3,5-di- tert -butyl-6-methoxymethylcatechol with different heterocyclic thiols. The S-functionalized catechols were prepared by the Michael reaction from 3,5-di- tert -butyl- o -benzoquinone and the corresponding thiols. The starting reagents such as substituted 1,3,4-oxadiazole-2-thiols and 4 H -triazole-3-thiols are characterized by thiol–thione tautomerism, therefore their reactions with 3,5-di- tert -butyl-6-methoxymethylcatechol can proceed at the sulfur or nitrogen atom. In the case of mercapto-derivatives of thiazole or pyridine, this process leads to the formation of the corresponding thioethers with a methylene linker. At the same time, thiolated 1,3,4-oxadiazole or 1,2,4-triazole undergo alkylation at the nitrogen atom in the reaction with 3,5-di- tert -butyl-6-methoxymethylcatechol to form the corresponding thiones. The yield of reaction products ranges from 42 to 80%. The crystal structures of catechols with 3-nitropyridine or 1,3,4-oxadiazole-2(3 H )-thione moieties were established by single-crystal X-ray analysis. The possibility of forming intra- and intermolecular hydrogen bonds has been established for these compounds. The electrochemical behavior of the studied compounds is influenced by several factors: the nature of the heterocycle and its substituents, the presence of a sulfur atom in the catechol ring, or a thione group in the heterocyclic core. The radical scavenging activity and antioxidant properties were determined using the reaction with synthetic radicals, the cupric reducing antioxidant capacity assay, the inhibition process of superoxide radical anion formation by xanthine oxidase, and the process of lipid peroxidation of rat liver ( Wistar ) homogenates in vitro.

Amphibians are known to possess a wide variety of compounds stored in their skin glands. While significant progress has been made in understanding the chemical diversity and biological relevance of alkaloids, amines, steroids, and peptides, most aspects of the odorous secretions are completely unknown. In this study, we examined sexual variations in the volatile profile from the skin of the tree frog Boana prasina and combined culture and culture-independent methods to investigate if microorganisms might be a source of these compounds. We found that sesquiterpenes, thioethers, and methoxypyrazines are major contributors to the observed sex differences. We also observed that each sex has a distinct profile of methoxypyrazines, and that the chemical origin of these compounds can be traced to a Pseudomonas sp. strain isolated from the frog’s skin. This symbiotic bacterium was present in almost all individuals examined from different sites and was maintained in captive conditions, supporting its significance as the source of methoxypyrazines in these frogs. Our results highlight the potential relevance of bacteria as a source of chemical signals in amphibians and contribute to increasing our understanding of the role that symbiotic associations have in animals.

Low-valent sulfur-containing compounds are abundant among natural and synthetic products but remain underutilized as starting materials in desulfurative transformations. Herein, we present thiols, disulfides, thioethers, and thioacetals as precursors in a direct desulfurative electrochemical process for the formation of alkylboronic esters, including late-stage functionalization of pharmaceutically relevant scaffolds and natural products. The electrochemical protocol is simple, user-friendly and scalable, successfully producing gram quantities of borylated product. Low-valent sulfur-containing compounds are abundant among natural and synthetic products but remain underutilized as starting materials in desulfurative transformations. Here, the authors present thiols, disulfides, thioethers, and thioacetals as precursors in a direct desulfurative electrochemical process for the formation of alkylboronic esters.