Search

This study aims to analyze the degradation behavior and mechanisms of amine-cured epoxy asphalt (EA) under the combined effects of ultraviolet (UV) radiation, oxygen, and temperature. To achieve this, amine-cured epoxy resin (ER) and EAs containing 35%, 45%, and 55% asphalt content were prepared and subjected to simulated UV-based aging. Various analytical techniques were employed to investigate the mechanical properties, microstructure, morphology, and oxidation layer of ER and EAs. The results indicate that after UV-based aging, ER and EAs with 35%–45% asphalt content experienced an increase in mass, a decrease in strength and glass transition temperature. In comparison, EAs with 55% asphalt content exhibited the opposite trends. The elongation and (Tanδ)max of ER and EAs reduced, whereas the storage modulus and hardness at mid to high temperatures rose. At the microstructural level, the degradation of the resin phase was confirmed by changes in ether, ester, and amide groups, whereas the generation of sulfoxide groups was associated with the oxidation of the asphalt phase. Compared with ER, the surface of EA has obvious defects after aging, which is the main reason for the decrease in contact angle. As the asphalt content increases, EAs exhibit higher carbonyl concentration, more profound oxidation, and more obvious performance degradation. This trend suggests that the resin phase mitigates the aging of the asphalt phase by absorbing harmful UV radiation and oxygen. [ABSTRACT FROM AUTHOR]

In this work, KIT‐6@Schiff‐base@Ce nanocatalyst was synthesized by immobilizing the Ce complex on KIT‐6 mesoporous silica framework modified with 3‐iodopropyltrimethoxysilane group. The surface area, total volume, and average diameter of pores, physical properties, functional groups, organic content, and element combination of the obtained nanocatalyst were identified using different techniques including BET, FT‐IR, XRD, WDX, SEM, and EDX. The KIT‐6@Schiff‐base@Ce was investigated as a novel stable and reusable catalyst with excellent performance for the selective synthesizing of sulfoxide and tetrahydrobenzo[b]pyrans. The designed catalyst successfully oxidized a large number of sulfides using hydrogen peroxide under solvent‐free conditions or in ethanol as a safe, green, and available solvent with good efficiency within short reaction times. Also, KIT‐6@Schiff‐base@Ce catalyzed a number of tetrahydrobenzo[b]pyrans using multicomponent condensation of dimedone, aldehydes, and malononitrile in water/ethanol (1:1) as ideal, safe, green and available solvent. [ABSTRACT FROM AUTHOR]

The properties of pavement bitumen deteriorates when exposed to complicated environmental factors. This study developed a multi-environment simulation device to apply multi-factor coupling on asphalt mixtures. The physicochemical properties of recovered bitumen were analysed by traditional technical indicators, tensile strength, fourier transform infrared spectroscopy, and contact angle tests. The ageing index and target functional group index ratio were proposed to quantify the interactions of environmental factors. The results indicated that surface morphology of mixtures was severely affected by multi-factor coupling. The multi-factor coupling exacerbated the deterioration of physical properties and increased tensile strength, surface free energy, and adhesion work. However, the sulfoxide index was more affected by thermal ageing than the carbonyl index, and its change under ultraviolet and multi-factor actions was not obvious. The ageing index and target functional group index ratio indicated that the effect of ultraviolet-thermal coupling had the largest effect on the physicochemical properties of bitumen. [ABSTRACT FROM AUTHOR]

Sulfoxides have emerged as pivotal constituents in modern carbohydrate chemistry. As anomeric leaving groups, sulfinyl moieties may occupy positions directly at the anomeric position or at a more remote site. This feature article is focused on the evolution and notable advancements of glycosyl sulfoxide donors in glycosylation reactions. Its objective is to elucidate the obstacles and prospects within this evolving research domain, with the aim of enhancing comprehension and progress in the field of carbohydrate chemistry. [ABSTRACT FROM AUTHOR]

Taking iodine-peroxide and diphenyldiselelen ether as raw materials, dimethyl sulfoxide as solvent, ammonium iodide and potassium tert-butoxide as catalysts, C Se bond coupling was formed at room temperature, and 11 selenium aryl peroxides were synthesized. By using HNMR spectroscopy, CNMR spectroscopy and mass spectrometry, the products were characterized and analyzed separately. Through a series of control experiments, the reaction was determined to be ionic and the corresponding reaction mechanism was inferred. The results show that 11 selenium aryl peroxides are all yellow liquid. The yield is 68%~85%. [ABSTRACT FROM AUTHOR]

Two new monooxygenase biocatalysts, the Baeyer–Villiger monooxygenase BVMO145 and the flavin monooxygenase FMO401 from Almac library, have been found to catalyse the enantiodivergent oxidation of sulfides bearing N-heterocyclic substituents into sulfoxides under mild and green conditions. The biocatalyst BVMO145 provides (S)-sulfoxides while the flavin monooxygenase FMO401 affords (R)-sulfoxides with good conversions and high ee. [ABSTRACT FROM AUTHOR]

A new method for the intramolecular electrophilic ipso -cyclization of alkynes with triflic anhydride-activated sulfoxides, followed by demethylation with triethylamine in one pot, is described for the synthesis of 3-thiospiro[4.5]-decatrienones in moderate to good yields. This method provides a facile strategy for assembling the sulfur-substituted spirocyclic compounds. [ABSTRACT FROM AUTHOR]

A recent interest attaches to the derivatives of the (2‐benzylsulfinyl)benzoic acid as inhibitors of human carbonic anhydrases (hCAs), an action that can be applied in innovative therapies. A set of crystal structures of six sulfides and six enantiopure sulfoxides related to this scaffold, taken from the literature, or derived from the work on the asymmetric synthesis of sulfinyl compounds, is investigated. The lattice energies of these structures are estimated by means of the Crystal Explorer 21 program. The weak interactions building up the crystal structures are identified, and their contributions are analyzed in comparison with the calculated lattice energies. The most stable conformations in the solid phase are identified. It is worth observing that the sulfides of the scaffold under investigation behave almost in the same manner; on the other hand, the presence of the sulfinyl group of the sulfoxides adds complexity, that shall be taken into account in future docking calculations of these molecules with the hCAs enzymes. [ABSTRACT FROM AUTHOR]

In this research project, a versatile procedure has been designed for the preparation of supported copper@curcumin on magnetic graphene oxide nanoparticles (GO@Fe3O4@Cur–Cu). The structure of prepared nanocatalyst was characterized by several techniques including; Fourier transform infrared, powder X-ray diffraction, thermal gravimetric analysis, energy dispersive X-ray analysis, inductively coupled plasma optical emission spectroscopy, vibrating sample magnetometer, transmission electron microscopy, and scanning electron microscopy analyses. The catalytic properties of GO@Fe3O4@Cur–Cu were examined for the efficient synthesis of polyhydroquinolines as well as the preparation of sulfoxides through selective oxidation of sulfides in the presence of hydrogen peroxide. [ABSTRACT FROM AUTHOR]

In the following research, meso‐tetrakis(4‐carboxyphenyl)porphyrinatomanganese (III) acetate (MnTCPP(OAc)) was immobilized onto the surface of two functionalized magnetic nanoparticles (MNPs) with different linker length via amide bond (Fe3O4@SiO2‐NH2‐MnTCPP(OAc) (A1) and Fe3O4@SiO2‐NHCO‐NH2‐MnTCPP(OAc) (A2)). The prepared catalysts were characterized by standard methods such as: atomic absorption spectroscopy (AAS), Ultra violet‐visible (UV‐Vis), Fourier‐transform infrared (FT‐IR), vibrating sample magnetometry (VSM), field emission scanning electron microscopy (FE‐SEM) and transmission electron microscopy (TEM) techniques and also the effect of the length of the linker on the catalytic activity of supported magnetic nanohybrids was investigated. The prepared magnetic nano‐catalysts with different linker lengths were participated in a comparative study of the clean oxidation of sulfides with urea hydrogen peroxide (UHP) in ethanol. The higher catalytic activity, selectivity and also reusability were achieved in the presence of the catalyst with longer linker length (A2) at ambient temperature. Moreover, the turnover number (TON) of catalytic reactions using A2 as catalyst was highly enough to consider the catalyst as an efficient material to oxidize various sulfides. Both A1 and A2 catalysts simply have accomplished 5 runs of recycling without significant decrease in the catalytic activity. [ABSTRACT FROM AUTHOR]

A transition‐metal‐free protocol is proposed for the selective oxidation of flavones, providing various sulfoxide/sulfone‐flavonoids in excellent yields. This strategy features excellent selectivities, high yields and broad substrate scope. The combination of oxone (2KHSO5 ⋅ KHSO 4⋅ K2SO4) as the sole oxidant and NaHCO3/Na2CO3 as the buffer play an important role in the process, in which the amounts of oxone and reaction temperatures are the key to the outstanding selectivities and high efficiency of the reaction. It should be noteworthy that a class of novel sulfone‐flavonols is also synthesized through triple oxidation. Moreover, the glycosylation of sulfone‐flavonols has been realized. [ABSTRACT FROM AUTHOR]

An advanced insulin synthesis is presented that utilizes one‐pot/stepwise disulfide bond formation enabled by acid‐activated S‐protected cysteine sulfoxides in the presence of chloride anion. S‐chlorocysteine generated from cysteine sulfoxides reacts with an S‐protected cysteine to afford S‐sulfenylsulfonium cation, which then furnishes the disulfide or reversely returns to the starting materials depending on the S‐protection employed and the reaction conditions. Use of S‐acetamidomethyl cysteine (Cys(Acm)) and its sulfoxide (Cys(Acm)(O)) selectively give the disulfide under weak acid conditions in the presence of MgCl2 even if S‐p‐methoxybenzyl cysteine (Cys(MBzl)) and its sulfoxide (Cys(MBzl)(O)) are also present. In contrast, the S‐MBzl pair yields the disulfide under more acidic conditions in the presence of a chloride anion source. These reaction conditions allowed a one‐pot insulin synthesis. Additionally, lipidated insulin was prepared by a one‐pot disulfide‐bonding/lipidation sequence. [ABSTRACT FROM AUTHOR]

Positron emission tomography (PET) is becoming increasingly important in nuclear medicine and drug discovery. To date, the development of many potential PET tracers is hampered by the lack of suitable synthetic pathways for their preparation. This is particularly true for the highly desired radiolabeling of compounds bearing [18F]CF3‐groups. For instance, S(O)nCF3‐groups (n=0, 1, 2) serve as structural motif in a range of biologically active compounds, but their radiosynthesis remains largely unprecedented (for n=1, 2). Herein, we describe general methods for the radiosynthesis of 18F‐labeled aryl trifluoromethyl sulfones, ‐sulfoxides, and ‐sulfides. All three methods are operationally straightforward, start from widely available precursors, i.e., sulfonyl fluorides and thiophenols, and make use of the recently established [18F]Ruppert‐Prakash reagent. Further, the syntheses display good functional group tolerance as demonstrated by the 18F‐labeling of more than 40 compounds. The applicability of the new method is demonstrated by the radiolabeling of three bioactive molecules, optionally to be used as PET tracers. In a broader context, this work presents a substantial expansion of the chemical space of radiofluorinated structural motifs to be used for the development of new PET tracers. [ABSTRACT FROM AUTHOR]

The transition metal‐catalyzed C−H activation of arenes directed by sulfoxides represents a compelling strategy in organic synthesis, owing to its exceptional regioselectivity and high efficiency. This innovative approach stands out for its traceless character, enabling the direct functionalization of arenes, before the easy removal or conversion of the key sulfinyl moiety. Beyond their utility as a directing group, sulfoxides have proved particularly valuable to mediate as chiral auxiliaries, presenting exciting prospects for the synthesis of stereo‐enriched compounds upon C−H functionalization. The versatility demonstrated by the method paves the way to different structures with potential applications ranging from medicinal chemistry to organic electronics. [ABSTRACT FROM AUTHOR]

A possibility of use of the Michael addition reaction of the A, Bring fragment enolate to sulfoxide 2(S)[(4methyl phenyl) sulfinyl]2cyclopenten1one for constructing the main skeleton of 9,11secosterols was studied. The reaction was conducted with the racemic or the enantiomerically enriched sulfoxide as the acceptor, affording a mixture of five or three main diastereomers, respectively. It was shown that the diastereoselectivity of that addition reaction is relatively low and does not afford a competitive new route for the total synthesis of secosterols. [ABSTRACT FROM AUTHOR]

The autophagosomal SNARE STX17 (syntaxin 17) promotes lysosomal fusion and degradation, but its autophagosomal recruitment is incompletely understood. Notably, PtdIns4P is generated on autophagosomes and promotes fusion through an unknown mechanism. Here we show that soluble recombinant STX17 is spontaneously recruited to negatively charged liposomes and adding PtdIns4P to liposomes containing neutral lipids is sufficient for its recruitment. Consistently, STX17 colocalizes with PtdIns4P-positive autophagosomes in cells, and specific inhibition of PtdIns4P synthesis on autophagosomes prevents its loading. Molecular dynamics simulations indicate that C-terminal positively charged amino acids establish contact with membrane bilayers containing negatively charged PtdIns4P. Accordingly, Ala substitution of Lys and Arg residues in the C terminus of STX17 abolishes membrane binding and impairs its autophagosomal recruitment. Finally, only wild type but not Ala substituted STX17 expression rescues the autophagosome-lysosome fusion defect of STX17 loss-of-function cells. We thus identify a key step of autophagosome maturation that promotes lysosomal fusion. Abbreviations: Cardiolipin: 1',3'-bis[1-palmitoyl-2-oleoyl-sn-glycero-3-phospho]-glycerol; DMSO: dimethyl sulfoxide; GST: glutathione S-transferase; GUV: giant unilamellar vesicles; LAMP1: lysosomal associated membrane protein 1; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; PA: 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphate; PC/POPC: 1-palmitoyl-2-oleoyl-glycero-3-phosphocholine; PG: 1-palmitoyl-2-linoleoyl-sn-glycero-3-phospho-(1'-rac-glycerol); PI: L-α-phosphatidylinositol; PI4K2A: phosphatidylinositol 4-kinase type 2 alpha; PIK3C3/VPS34: phosphatidylinositol 3-kinase catalytic subunit type 3; POPE/PE: 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine; PS: 1-stearoyl-2-linoleoyl-sn-glycero-3-phospho-L-serine; PtdIns(3,5)P2: 1,2-dioleoyl-sn-glycero-3-phospho-(1"-myo-inositol-3',5'-bisphosphate); PtdIns3P: 1,2- dioleoyl-sn-glycero-3-phospho-(1'-myo-inositol-3'-phosphate); PtdIns4P: 1,2-dioleoyl-sn-glycero-3-phospho-(1"-myo-inositol-4'-phosphate); SDS-PAGE: sodium dodecyl sulfate-polyacrylamide gel electrophoresis; STX17: syntaxin 17. [ABSTRACT FROM AUTHOR]

A possibility of use of the Michael addition reaction of the A,B-ring fragment enolate to sulfoxide 2­-(S)-­[(4­-methylphenyl)sulfinyl]-­2­-cyclopenten-1­-one for constructing the main skeleton of 9,11-secosterols was studied. The reaction was conducted with the racemic or the enantiomerically enriched sulfoxide as the acceptor, affording a mixture of five or three main diastereomers, respectively. It was shown that the diastereoselectivity of that addition reaction is relatively low and does not afford a competitive new route for the total synthesis of secosterols.

[Display omitted] Selective oxidation of sulfur mustard gas (HD) to non-toxic sulfoxide by the visible-light-catalyzed generation of singlet oxygen (1O 2) is a promising degradation strategy. Although PCN-224 can absorb visible light, it suffers from rapid electron-hole recombination and low redox capacity, which limits the performance of HD degradation. Titanium dioxide (TiO 2) is an excellent photocatalyst but it lacks visible-light-activity in degrading HD. In this study, PCN-224@TiO 2 heterojunction with S-type core–shell structure was synthesized by in-situ growth method to prolong the visible light absorption capacity of TiO 2 and inhibit the rapid recombination of PCN-224. The interface formation and internal electric field were optimized by adjusting the Zr/Ti ratio to enhance the charge transfer, redox capacity, electron-hole separation, and visible light absorption. In this study, the formation of heterojunction composites based on Zr-O-Ti linkages is demonstrated by a series of characterization methods. It is demonstrated by experiments and theoretical calculations that PCN-224@TiO 2 can generate nearly 100 % 1O 2 under visible light conditions without a sacrificial agent, resulting in efficient and selective oxidation of 2-chloroethyl ethyl sulfide (CEES), a simulant of HD, to non-toxic sulfoxide form. [ABSTRACT FROM AUTHOR]

Tandem aromatic rearrangements represent a potent strategy for modulating the regioselectivity of a rearrangement process. In this article, we disclose two novel tandem aromatic rearrangements triggered by sulfonium [5,5]-rearrangement recently developed in our laboratory. Specifically, the [5,5]-rearrangement of aryl sulfoxides with allyl nitriles, followed by [3,3]-Cope rearrangement, forges a seamless tandem [5,5]-/[3,3]-rearrangement cascade, affording ortho -functionalized aryl sulfides. The other tandem process involves [5,5]-rearrangement of aryl sulfoxides with allyl nitriles, followed by nucleophilic addition/DDQ-oxidation-induced [3,3]-Cope rearrangement, eventually yielding meta -functionalized aryl sulfides. Both consecutive rearrangements enrich the repertoire of tandem aromatic rearrangement methodologies. [ABSTRACT FROM AUTHOR]

A visible-light induced selective oxidation of sulfides to sulfoxides or sulfones was reported at ambient temperature in H2O under catalyst-free conditions, using oxygen as a green oxidant. The surfactants play a key role in this oxidation, and sulfoxides or sulfones were obtained in high yields, respectively, promoted by different surfactants. [ABSTRACT FROM AUTHOR]

Aqueous soft matter, including supramolecular hydrogels capable of exhibiting stimuli–responsive macroscopic phase transitions, has attracted increasing attention for the exploration of functional soft materials. However, the investigation of supramolecular hydrogels that undergo autonomous and multiple macroscopic phase transitions (e.g., gel–sol–gel, sol–gel–sol) in response to the surrounding environment without repeated additions of stimuli has remained largely unexplored. In this study, the oxidation‐responsive autonomous gel–sol–gel transitions of supramolecular hydrogels fabricated via the self‐assembly of a simple fluorenylmethyloxycarbonyl (Fmoc)‐protected, benzylated cysteine (Fmoc‐CBzl) is presented. During the evaluation of the oxidation process of Fmoc‐CBzl, it is revealed that the oxidized products, two diastereomeric sulfoxides (Fmoc‐CBzl‐(R)‐O and Fmoc‐CBzl‐(S)‐O), exhibit significantly different self‐assembly propensities under aqueous conditions. It may be noteworthy that the chirality of sulfoxide is largely overlooked and not effectively used to modulate supramolecular, self‐assembled nanostructures. The difference in the self‐assembly propensities and kinetics of self‐assembly/disassembly as well as co‐assembly will contribute to oxidation‐responsive autonomous gel–sol–gel transitions. [ABSTRACT FROM AUTHOR]

Photocatalytic selective oxidation represents an eco-friendly strategy for chemical transformation. Herein, a lead-free halide perovskite Cs3Bi2Br9 combined with TiO2 was facilely synthesized and applied for efficient photocatalytic selective oxidation of sulfides to sulfoxides with high yields and good compatibility under mild conditions. The Cs3Bi2Br9/TiO2 composite exhibited enhanced photocatalytic activity compared to bare Cs3Bi2Br9 particles, which could be ascribed to the strong interaction between Cs3Bi2Br9 NCs and TiO2 markedly accelerating the separation and transfer efficiency of photogenerated electron–hole pairs and simultaneously suppressing their recombination. [ABSTRACT FROM AUTHOR]

This document provides information on the synthesis and characterization of several compounds. The compounds are derivatives of 1,3-dienyl sulfides and have various functional groups. The document includes details such as the yield, physical properties, and spectroscopic data for each compound. The compounds are synthesized using different reactions and purification methods. The information provided can be useful for researchers studying organic chemistry and chemical synthesis. [Extracted from the article]

[Display omitted] Developing efficient catalysts for the selective oxidation of sulfides to sulfoxides using molecular oxygen as the oxidant is a challenging task. Here, we report a novel catalyst comprising a single atom palladium engineered cobalt nanocomposite (denoted as PdCo@NC-800–0.01) for this reaction. The incorporation of single atom palladium effectively transforms an originally inactive cobalt nanocomposite into a highly efficient and selective catalyst for the oxidation of sulfides. This catalyst PdCo@NC-800–0.01 exhibited outstanding performance in the selective oxidation of sulfides to sulfoxides using O 2 as the oxidant in the presence of isobutyraldehyde (IBA) under mild conditions, demonstrating high activity and excellent selectivity for a broad spectrum of sulfides with good tolerance toward various functional groups, including those susceptible to oxidation. Furthermore, the catalyst could be easily recovered and reused up to 10 times without any significant loss in activity and selectivity. Comprehensive characterizations and theoretical calculations revealed that the engineering of cobalt nanocomposite with single atom Pd greatly enhanced the ability to adsorb and activate IBA, leading to the generation of the key acyl radical. This radical then reacted with singlet oxygen 1O 2 derived from molecular oxygen, producing reactive oxygen species peroxy radical, which ultimately promoted the catalytic performance. [ABSTRACT FROM AUTHOR]

AbstractLiposomes are widely used for smart delivery due to their biodegradability and biocompatibility. Recently, liposomes have been developed to respond to dual and multi-stimuli. This development leads to the potential for superior in vitro and in vivo drug delivery in the future. In this study, egg PC liposomes responsive to temperature, oxidation, and NIR irradiation were prepared by modifying the liposomal membranes with poly(hydroxyethyl acrylate-co-ethyl vinyl sulfide) (P(HEA-co-EVS)) and including indocyanine green (ICG) in the liposomes.The copolymer was found to exhibit a lower critical solution temperature (LCST) and it was oxidizable and surface-active.On the TEM photos of the liposomes, multi-lamellar vesicles were found and the size was in accordance with the hydrodynamic diameter. The liposomes released their payload in response to H2O2 concentration possibly because the EVS was oxidized by the oxidizing agent. The liposome exhibited a temperature-responsive release possibly due to the thermal contraction of the copolymer chains.In addition, the release was triggered when a near-infrared(NIR) laser was irradiated to the liposome suspensions. Under NIR irradiation, the photosensitizer (i.e. ICG) can generate heat and reactive oxygen species, which, in turn, would induce the conformational and polarity change of the polymer chains, leading to a release. [ABSTRACT FROM AUTHOR]

A heterogeneous photocatalyst was assembled through electrostatic immobilization of a cationic porphyrin at the surface of functionalized carbon nanotubes. The supra‐molecular nanohybrid catalyst was valorized in the aerobic photo‐oxidation of sulfides to the corresponding sulfoxides. The process operated selectively under visible light, with low catalytic loading, in water as the solvent, and the catalyst was readily recycled and reused. [ABSTRACT FROM AUTHOR]

Development of efficient, stable, and recyclable photocatalysts for organic synthesis is vital for transformation of traditional thermal organic chemistry into green sustainable organic chemistry. In this work, the study reports an electrostatic approach to assemble meso‐tetra (4‐sulfonate phenyl) porphyrin (TPPS)tetra (4‐sulfonate phenyl) porphyrin (TPPS) as a donor and benzyl viologen (BV) as an acceptor into stable and recyclable photocatalyst for an efficient organic transformation reaction – aryl sulfide oxidation. By use of the electrostatic TPPS‐BV photocatalysts, 0.1 mmol aryl sulfide with electron‐donating group can be completely transformed into aryl sulfoxide in 60 min without overoxidation into sulfone, rendering near 100% yield and selectivity. The photocatalyst can be recycled up to 95% when 10 mg amount is used. Mechanistic study reveals that efficient charge separation between TPPS and BV results in sufficient formation of superoxide which further reacts with the oxidized sulfide by the photocatalyst to produce the sulfoxide. This mechanistic pathway differs significantly from the previously proposed singlet oxygen‐dominated process in homogeneous TPPS photocatalysis. [ABSTRACT FROM AUTHOR]

This article explores the use of bicyclopentane (BCP) as a bioisostere in medicinal chemistry. BCP can replace phenyl rings or alkynes in molecules, altering their physical properties. The authors focus on the synthesis of BCP-sulfoxides, which can enhance the pharmacological properties of compounds. They present a new method using a BCP-sulfinate precursor that is more convenient and stable. The authors successfully synthesized a previously inaccessible methyl-substituted sulfoxide and suggest the potential for further modifications. [Extracted from the article]

Herin, we demonstrate the synthesis and catalytic efficacy of Fe3O4@SiO2-Amine-DAB/Py-CuCl2 nanocomposite as a novel catalyst in synthesizing various 2,3,5-triaryl furans via oxidative cyclization of aryl ketones with styrenes and oxidation of sulfides to sulfoxides under eco-friendly conditions. Our catalytic system accommodates a broad substrate scope, encompassing aryl ketones, styrenes, and aryl sulfides with both withdrawing and donating groups on the ring, yielding target products with high yields. Additionally, the catalyst exhibits notable reusability, maintaining stable efficiency over seven runs, as confirmed by VSM, TEM, and ICP-OES analyses, which validate the structural integrity of Fe3O4@SiO2-Amine-DAB/Py-CuCl2 even after eight recovery cycles. The developed Fe3O4@SiO2-Amine-DAB/Py-CuCl2 nanocomposite catalyst, demonstrating its efficiency and reusability in synthesizing 2,3,5-triaryl furans and diaryl sulfoxides under environmentally friendly conditions, which contributes significantly to the advancement of green catalysis methodologies. [ABSTRACT FROM AUTHOR]

Thioether (sulfide) profragrances are readily prepared by 1,4‐addition of alkanethiols to enones (thia‐Michael reaction). Under ambient conditions, they slowly release the parent enones, thus generating a long‐lasting perfumery effect. The fragrance release of profragrances obtained by 1,4‐addition of S, O and N nucleophiles to enones was compared on cotton and on a hard surface for monomeric and dimeric structures. To avoid the uncontrolled generation of volatile sulfur compounds from thioethers, we investigated the extent to which different side reactions occurred next to the expected formation of enones and alkanethiols. Headspace analyses on cotton showed that enones and aldehydes were the major reaction products, whereas none or only traces of β‐mercaptoketones, diketones or alkanethiols were detected. The absence of alkanethiols indicated that 1,4‐elimination of thioethers was not a major pathway for fragrance release. Extraction of the cotton sheets after analysis showed that thioethers were oxidised to sulfoxides, which then can generate enones by 1,4‐elimination. Thioethers, sulfoxides and sulfones were shown to efficiently release enones in practical applications. [ABSTRACT FROM AUTHOR]

Targeting the challenges of inadequate charge separation and insufficient molecular activation within the photocatalyst, we have successfully developed a novel supramolecular polarization photocatalyst with methylphosphate-substituted PDI (P-PDIP), which features a significant built-in electric field, resulting in substantial enhancements in both charge separation efficiency and molecule activation efficiency, thereby paving the way for an efficient and stable photocatalytic selective aerobic oxidation of sulfides. [Display omitted] • A novel P-PDIP supramolecular polarization photocatalyst is constructed for selective aerobic oxidation of sulfide. • A giant build-in electric field is produced in P-PDIP by molecular dipole modulation and polar molecular self-assembly. • The incorporation of methylphosphate groups improves the activation efficiency of O 2 and thioether molecules. • The P-PDIP achieves 99.9% conversion and 99.8% selectivity in the aerobic oxidation of methyl phenyl sulfide to sulfoxide. Photocatalytic aerobic oxidation is a promising sustainable strategy for the selective organic synthesis of industrially valuable chemicals. However, the poor charge separation and insufficient molecular activation restrict the overall photocatalytic efficiency. To address these issues, we have developed a novel approach involving molecular dipole modulation and polar molecular self-assembly to modulate the built-in electric field (BEF) in perylene diimide (PDI) supramolecular polarization photocatalysts by adjusting the electronegativity of terminal substituents. The optimized methylphosphate-substituted PDI (P-PDIP) supramolecular system features the strongest BEF induced by its large molecular dipole, with an intensity 3.89 times higher than that observed in methylcarboxy-substituted PDI (P-PDIC) and 5.64 times higher than that observed in P-PDI. This significant enhancement in BEF generates a powerful driving force within P-PDIP, facilitating directional charge separation toward active sites. Additionally, the incorporation of methylphosphate groups improves the activation efficiency of O 2 and thioether molecules, resulting in a remarkable photocatalytic performance for selective aerobic oxidation of sulfides into sulfoxide (up to 99.9% conversion and 99.8% selectivity). This study highlights that enhancing BEF through manipulating molecular dipoles can significantly improve photocatalytic activity, offering great potential for constructing efficient organic polarization photocatalysts in green chemistry and sustainable production. [ABSTRACT FROM AUTHOR]

Upon morphology control and in-situ strategy, the photoactive CdS were immobilized to the highly ordered hollow hemispherical microstructure Co-CP (1a) to fabric CdS@1a composites, which had a well-defined platform with uniformly dispersed and readily accessible active sites to perform photocatalytic selective oxidation reactions in air under blue LEDs. [Display omitted] Accurately controlling and achieving selective reactivity at difficult-to-access reaction sites in organic molecules is challenging owing to the similar local and electronic environments of multiple reaction sites. In this work, we regulated multiple reaction sites in a highly selective and active manner using cobalt coordination polymers (Co-CP) 1 and 1a with various particle sizes and morphologies ranging from large granular to ordered hollow hemispheres by introducing sodium dodecyl sulfate (SDS) as a surfactant. The size and morphology of the catalysts could be tuned by controlling the amount of SDS. An SDS concentration of 0.03 mmol generated 1a having a highly ordered hollow hemispherical microstructure with a well-defined platform as a pre-made building unit. Cadmium sulfide (CdS), as a typical photocatalyst, was subsequently uniformly anchored in-situ on the premade building unit 1a to produce CdS@1a composites, that inherited the originally ordered hollow hemispherical microstructure while integrating CdS as well-dispersed catalytic active sites. Furthermore, the well-established CdS@1a composites were used as photocatalysts in selective oxidation reactions under air atmosphere with blue irradiation. The CdS 0.109 @1a composite with unique structural characteristics, including uniformly distributed and easily accessible catalytic sites and excellent photoelectrochemical performance, served as a highly efficient heterogeneous photocatalyst for promoting the selective oxidation of sulfides to sulfoxides as the sole products. This work presents an approach for fabricating CPs as premade building units that function as well-defined platforms for integration with photocatalysts, enabling tuning of the structure-selectivity-activity relationships. [ABSTRACT FROM AUTHOR]

A novel strategy for the chemoselective conversion of sulfoxides to sulfide utilizing D-camphorsulfonic acid (D-CSA) as a reducing reagent has been developed under metal and additive-free conditions. A variety of sulfoxides such as alkyl–aryl, allyl–aryl, benzyl–aryl, aryl–ethyl sulfoxides have been effectively utilized to achieve the corresponding reduced products in good to excellent yields under mild conditions without any additive. The proposed method offers a practical solution for the deoxygenation of sulfoxides, which has potential applications in various fields such as pharmaceuticals, materials science, and organic synthesis. A novel strategy for the chemoselective deoxygenation of diverse sulfoxides without metal and additive has been disclosed using D-camphorsulfonic acid (D-CSA) as the reducing agent. The reaction proceeds under mild conditions to afford the sulphides in moderate to good yields with great tolerance of diverse functional groups. [ABSTRACT FROM AUTHOR]

Regulating the doping of carbon dots (CDs) and the generation of reactive oxygen species (ROS) is essential to selectively control their application in photocatalytic organic reactions. This study successfully synthesized five newly developed nitrogen-doped carbon dots (CDs 1–5) with varying nitrogen content, which have the ability to generate ROS when exposed to light radiation, specifically superoxide anion radicals ( O 2 - ) and singlet oxygen (1O2). The utilization of the aforementioned nitrogen-doped CDs as photocatalysts enables the realization of their potential in facilitating efficient photocatalytic organic conversion. Simultaneously, it was observed that the photocatalytic efficiency exhibited a gradual decrease when the nitrogen content in the CDs increased. In order to provide more evidence for this claim, we employed a set of five CDs in the context of photocatalytic dehalogenation of α-bromoacetophenone, photocatalytic oxidative coupling reaction of amines to imines, photooxidation reaction of sulfides to sulfoxides, and cross-dehydrogenation coupling (CDC) reaction, in which it was further observed that there was a steady decrease in the yields of photocatalytic organic reactions as the nitrogen content in CDs increased. Notably, CDs 1 exhibited the best photocatalytic efficiency, thereby reinforcing the hypothesis that a higher nitrogen content corresponds to a decreased catalytic efficiency. This study not only investigates the impact of the nitrogen content on the catalytic performance of CDs, but also offers valuable insights for the future utilization of CDs for photocatalytic organic reactions in water. [ABSTRACT FROM AUTHOR]

Dimethyl sulfoxide as a reagent and solvent in Selectfluor mediated transformations of isatin is reported. The transformations include N‐methylation and N‐methylenesulfonylmethylation of isatin at 100 °C whereas N‐methylenethiomethylation was observed at 140 °C in addition to N‐methylation and N‐methylenesulfonylmethylation of isatins. Electron withdrawing and releasing substituents on isatin were tolerated. Interestingly, dual (N‐ and C−)methylenethiomethylation was observed in case of 7‐Bromo‐ and 7‐Iodo isatins at 140 °C. This protocol efficiently afforded various isatin analogs using DMSO/Selectfluor system. [ABSTRACT FROM AUTHOR]

Sulfoxides are remarkably useful in asymmetric synthesis and drug development. Herein, we propose a new electroenzymatic cascade route to selectively synthesize methyl phenyl sulfoxide rather than methyl phenyl sulfone by the oxidation of thioanisole. Chloroperoxidase (CPO) functionalized with 1-ethyl-3-methylimidazolium bromide (ILEMB) is encapsulated into dendritic N-doped mesoporous carbon nanospheres (NMCNs) modified with polyethyleneimine (NMCNs-PEI) to form a biohybrid (CPO-ILEMB@NMCNs-PEI). The in situ generation of hydrogen peroxide (H2O2) species by the two-electron oxygen reduction reaction (2e−ORR) on NMCNs-PEI initiates the subsequent selective oxidation of thioanisole by CPO-ILEMB. NMCNs-PEI shows not only high electroactivity for the 2e−ORR but also good biocompatibility for CPO-ILEMB immobilization. The mesopores in NMCNs-PEI can provide a protective space for the encapsulated enzyme, ensuring the operational stability of the enzyme and avoiding the escape of H2O2, which result in high catalytic activity. The experimental results suggest that the catalytic efficiency of the electroenzymatic cascade system with the CPO-ILEMB@NMCNs-PEI biohybrid is up to 4.5 times higher than that of the free CPO-ILEMB catalytic system with H2O2 generated by NMCNs-PEI for the oxidation of thioanisole to produce methyl phenyl sulfoxide. [ABSTRACT FROM AUTHOR]

The phenomenon of polymorphism is ubiquitous in nature, the controlled manipulation of which not only increases our ontological understanding of nature but also facilitates the conceptualization and realization of novel functional materials. However, achieving targeted polymorphism in supramolecular assemblies (SAs) remains a formidable challenge, largely because of the constraints inherent in controlling the specific binding motifs of noncovalent interactions. Herein, we propose self‐adaptive aromatic cation‐π binding motifs to construct polymorphic SAs in both the solid and solution states. Using distinct discrete cation‐π‐cation and long‐range cation‐π binding motifs enables control of the self‐assembly directionality of a C2h‐symmetric bifunctional monomer, resulting in the successful formation of both two‐dimensional and three‐dimensional crystalline SAs (2D‐CSA and 3D‐CSA). The differences in the molecular packing of 3D‐CSA compared with that of 2D‐CSA significantly improve the charge separation and carrier mobility, leading to enhanced photocatalytic activity for the aerobic oxidation of thioanisole to methyl phenyl sulfoxide (yield of 99 % vs 57 %). 2D‐CSA, which has a vertical extended structure with favorable stronger interaction with toluene though face‐to‐face cation‐π interactions than methylcyclohexane, shows higher toluene/methylcyclohexane separation efficiency than 3D‐CSA (96.9 % for 2D‐CSA vs 56.3 % for 3D‐CSA). [ABSTRACT FROM AUTHOR]

Three Ti–O clusters and a Tb–Ti–O cluster capped by p-tert-butylcalix[8]arene (H8C8A), namely, [Ti7O8(C8A)(CH3O)4(CH3OH)4] (CIAC-262), [Ti13O15(C8A)2(CH3O)6(CH3OH)3(H2O)2] (CIAC-263), [Ti24O28(OH)8(C8A)4(DMF)2(H2O)2] (CIAC-264) and [Tb2Ti13O15(OH)4(H3C8A)(C8A)2(HCOO)3(DMF)4(H2O)] (CIAC-265), were prepared by controlling the amount of methanol in the reaction system under solvothermal conditions. The amount of methanol is reduced from 4 mL to 2 mL and then to 0 mL, resulting in a {Ti7} cluster with Ti7–C8A unit, a {Ti13} cluster constructed by two perpendicular tail-to-tail Ti7–C8A units with a vertex-shared mode, and a {Ti24} cluster assembled by linking two Ti10–(C8A)2 units generated by the symmetric operation with a Ti4 entity, respectively. To replace the Ti4 linker in the {Ti24} cluster, Tb ions were incorporated in the methanol-free system. Then a {Tb2Ti13} cluster constructed by linking a Ti10–(C8A)2 unit and a Ti2–C8A entity with a Tb2Ti linker was obtained. Catalytic sulfoxidation experiments were performed to evaluate the structure–property relationships in these calixarene-based clusters. Driven by Ti atoms and active Ti sites with higher steric hindrance, compound CIAC-264 efficiently catalyzes the selective oxidation of methyl phenyl sulfide to methyl phenyl sulfoxide (96.00% for conversion and 98.28% for selectivity) using 30% H2O2 under mild conditions (298 K). Calixarene molecules in CIAC-264 protect the Ti–O cluster from decomposition during the catalytic reaction, which could be directly observed from MALDI-TOF MS spectra. This work not only opens a new insight for preparing high-nuclearity Ti–calixarene clusters with interesting assemblies but also provides new stable titanium oxide candidates for selective oxidation of organic sulfides. [ABSTRACT FROM AUTHOR]

Recent advances in visible light photocatalysis represent a significant stride towards sustainable catalytic chemistry. However, its successful implementation in fine chemical production remains challenging and requires careful optimization of available photocatalysts. Our work aims to structurally modify bioinspired porphyrin catalysts, addressing issues related to their laborious synthesis and low solubility, with the goal of increasing their efficiency and developing reusable catalytic systems. We have demonstrated the catalytic potential of readily available meso-tetrakis[4-(diethoxyphosphoryl)phenyl]porphyrins (M(TPPP)). Novel metal (Pd(II), Co(II) and In(III)) complexes with this ligand were prepared in good yields. These chromophores were characterized in solution using spectroscopic (NMR, UV-vis, fluorescence) and electrochemical methods. The introduction of phosphonate groups on the phenyl substituents of mesotetraphenylporphyrins (M(TPP)) improves solubility in polar organic solvents without significantly altering the photophysical properties and photostability of complexes. This structural modification also leads to easier reductions and harder oxidations of the macrocycle for all investigated complexes compared to the corresponding TPP derivatives. The free base porphyrin, zinc(II), palladium(II), and indium(III) complexes were studied as photocatalysts for oxidation of sulfides to sulfoxides using molecular oxygen as a terminal oxidant. Both dialkyl and alkyl aryl sulfides were quantitatively transformed into sulfoxides under blue LED irradiation in the acetonitrile-water mixture (10: 1 v/v) with a low loading (0.005-0.05 mol%) of porphyrin photocatalysts, where H2(TPPP) and Pd(TPPP) were found to be the most efficient. The reaction mechanism was studied using photoluminescence and EPR spectroscopies. Then, to access reusable catalysts, water-soluble derivatives bearing phosphonic acid groups, H2(TPPP-A) and Pd(TPPP-A), were prepared in high yields. These compounds were characterized using spectroscopic methods. Single-crystal X-ray diffraction analysis of Pd(TPPP-A) reveals that the complex forms a 3D hydrogen-bonded organic framework (HOF) in the solid state. Both H2(TPPP-A) and Pd(TPPP-A) were found to catalyze the photooxidation of sulfides by molecular oxygen in the acetonitrile-water mixture (1: 1 v/v), while only Pd(TPPP-A) resulted in selective production of sulfoxides. The complex Pd(TPPP-A) was easily recovered through extraction in the aqueous phase and successfully reused in five consecutive cycles of the sulfoxidation reaction. [ABSTRACT FROM AUTHOR]

The combination of excellent electronic properties and thermal stability positions orange‐derived graphene quantum dots (GQDs) as promising materials for solar light‐based applications. Researchers are actively exploring their potential in fields such as photovoltaics, photocatalysis, optoelectronics, and energy storage. Their abundance, cost‐effectiveness, and eco‐friendly nature further contribute to their growing relevance in cutting‐edge scientific research. Furthermore, only GQDs are not much more effective in the UV‐visible region, therefore, required band gap engineering in GQDs material. In this context, we designed GQDs‐based light harvesting materials, which is active in UV‐visible region. Herein we synthesized GQDs coupled with 2,6‐diaminoanthrquninone (AQ), that is, GQDs@AQ light harvesting photocatalyst the first time for the oxidation of sulfide to sulfoxide under visible light. For the integrating reactions of sulfide in aerobic conditions under visible light by GQDs@AQ photocatalyst exhibit utmost higher photocatalytic activity than simple GQDs due to low molar extinction coefficient and slow recombination charges. The use of GQDs@AQ light harvesting photocatalyst, showed the excellent organic transformation efficiency of sulfide to sulfoxide with excellent yield (94%). The high efficiency and excellent yield of 94% indicate the effectiveness of GQDs@AQ as a photocatalyst for these specific organic transformations. [ABSTRACT FROM AUTHOR]

Herein, we demonstrated a visible light mediated tandem oxidation–organo catalyzed C−S bond functionalization protocol for the cleavage of aromatic C−S bond. The investigation encompassed the functionalization of C−S bonds within sulfones, sulfoxides, and aliphatic sulfide derivatives. However, the process of functionalizing the C−S bond in aromatic sulfides remains uncertain. The presented protocol demonstrates the C−S bond functionalization on benzo[b]benzo[4,5]thieno[2,3‐d]thiophene derivative and amines including primary and secondary amines as well. A radical mediated mechanism was proposed for the tandem oxidation–organocatalyzed C−S bond functionalization protocol. [ABSTRACT FROM AUTHOR]

NMR is widely considered the gold standard for organic compound structure determination. As such, NMR is routinely used in organic compound identification, drug metabolite characterization, natural product discovery, and the deconvolution of metabolite mixtures in biofluids (metabolomics and exposomics). In many cases, compound identification by NMR is achieved by matching measured NMR spectra to experimentally collected NMR spectral reference libraries. Unfortunately, the number of available experimental NMR reference spectra, especially for metabolomics, medical diagnostics, or drug-related studies, is quite small. This experimental gap could be filled by predicting NMR chemical shifts for known compounds using computational methods such as machine learning (ML). Here, we describe how a deep learning algorithm that is trained on a high-quality, "solvent-aware" experimental dataset can be used to predict 1H chemical shifts more accurately than any other known method. The new program, called PROSPRE (PROton Shift PREdictor) can accurately (mean absolute error of <0.10 ppm) predict 1H chemical shifts in water (at neutral pH), chloroform, dimethyl sulfoxide, and methanol from a user-submitted chemical structure. PROSPRE (pronounced "prosper") has also been used to predict 1H chemical shifts for >600,000 molecules in many popular metabolomic, drug, and natural product databases. [ABSTRACT FROM AUTHOR]

An unusual benzofuran synthesis from 2,6-disubstituted phenols and alkynyl sulfoxides is disclosed. Various highly substituted benzofurans were synthesized via the charge-accelerated [3,3]-sigmatropic rearrangement and subsequent substituent migration. Multiaryl-substituted benzofurans and fully substituted benzofurans were prepared on the basis of the unique reaction mechanism. [ABSTRACT FROM AUTHOR]

DMSO-inspired polymer is frequently applied in advanced biomedical aspects due to its highly hydrophilic, excellent biocompatibility, and negligible cytotoxicity nature. Herein, our study aimed for the first time to synthesize electrospun poly((2-methylsulfinyl)ethyl acrylate-co-acrylic acid) (PMSEA-AA) nanofibers as wound dressing materials. PAA was initially grafted through a steglich esterification reaction to obtain poly(2-(methylthio)ethyl acrylate-co-acrylic acid) copolymer (PMTEA-AA). Subsequently, the obtained copolymer was further oxidized and exposed to electrospinning to give PMSEA-AA nanofiber-containing sulfoxide groups. The chemical structure of as-obtained polymers was carefully confirmed by FTIR, UV–vis, 1H-NMR, TGA, DSC, and GPC. Further, PMSEA-AA nanofibers were observed with remarkable mechanical, hydrophilic, cell viability, and antibacterial behaviors. The tensile strength and elongation at a break for PMSEA-AA nanofibers were recorded as 9 MPa and 30%, which are higher compared to PAA fibers (6.33, 20%). The cell growth of PMTEA-AA nanofiber was considerably increased concerning pure PAA nanofiber approving the nontoxic capability due to the hydrophobicity nature and high surface area that can lead to effective contact with the cancer cells. Also, PMSEA-AA nanofiber could achieve superior bacterial inhibition zones of 12 and 9 mm for S. aureus and E. coli, respectively, compared to PAA. PMSEA-AA nanofibers could discover biomedical and pharmaceutical applications for wound healing materials, tissue engineering, and transdermal drug delivery system for skin and oral. [ABSTRACT FROM AUTHOR]

Aerobic photooxidation in the aqueous phase is a promising field, but it faces the challenge of water-induced photocatalyst deactivation. In this work, we prepared three TADF-based photocatalysts with enhanced hydrophobicity to protect the excited state against water. Efficient aerobic photooxidation of sulfides into sulfoxides was realized in water owing to their extended triplet state lifetimes. The recyclability and oxidation mechanism of the photocatalyst were also discussed. [ABSTRACT FROM AUTHOR]

Iron nanoparticles, with low toxicity and many active sites, are among the materials that not only reduce waste along with green chemistry but also increase the separation power and recover the catalyst from the reaction environment. In this study, first, the surface of iron nanoparticles was silanized, and in the next step, the complex of chitosan HCl.VO3 was placed on the surface of Fe3O4 (Fe3O4@SiO2@CSH+VO3−). This nanocatalyst is a novel, recoverable, and potent nanocatalyst with high selectivity for the oxidation of sulfides to sulfoxides. Various physicochemical techniques such as IR, XRD, TGA, SEM, EDX, mapping, TEM, and VSM were used to affirm the well synthesis of the catalyst. Oxidation of sulfides in the presence of hydrogen peroxide as a green oxidant and in ethanol was catalyzed by the Fe3O4@SiO2@CSH+VO3−. All sulfoxides were achieved with high efficiency and in a short time. The notable privileges of this method include facile and economic catalyst synthesis, proper catalyst durability, great performance, simple catalyst isolation, good recovery capability, at least up to 5 times without an index drop in catalytic power. [ABSTRACT FROM AUTHOR]

Organic molecules containing fluorine and sulfur atoms represent a large percentage of approved pharmaceuticals. Those with combination of both S and F atoms in their structure such as Xtandi, approved in 2012 for prostate cancer, indicates the importance of synthetic methods that accommodates both atoms in an organic moiety. In this study, a novel aspect of sulfoxonium ylide reactivity was explored, unveiling a streamlined and mild synthesis method for gem‐difluorinated keto‐sulfoxides. Our protocol offers a direct and practical approach to prepare these compounds in 14–80 % chemical yields, that were represented by 21 examples. NMR studies and Hammett correlations gave strong evidence about the mechanism of this transformation. [ABSTRACT FROM AUTHOR]

Optically pure sulfoxides are valuable organosulfur compounds extensively employed in medicinal and organic synthesis. In this study, we present a biocatalytic oxidation‐reduction cascade system designed for the preparation of enantiopure sulfoxides. The system involves the cooperation of a low‐enantioselective chimeric oxidase SMO (styrene monooxygenase) with a high‐enantioselective reductase MsrA (methionine sulfoxide reductase A), facilitating "non‐selective oxidation and selective reduction" cycles for prochiral sulfide oxidation. The regeneration of requisite cofactors for MsrA and SMO was achieved via a cascade catalysis process involving three auxiliary enzymes, sustained by cost‐effective D‐glucose. Under the optimal reaction conditions, a series of heteroaryl alkyl, aryl alkyl and dialkyl sulfoxides in R configuration were synthesized through this "one‐pot, one step" cascade reaction. The obtained compounds exhibited high yields of >90 % and demonstrated enantiomeric excess (ee) values exceeding 90 %. This study represents an unconventional and efficient biocatalytic way in utilizing the low‐enantioselective oxidase for the synthesis of enantiopure sulfoxides. [ABSTRACT FROM AUTHOR]

2,6-Diaryl-4H-tetrahydro-thiopyran-4-ones and corresponding sulfoxide and sulfone derivatives were designed to lower the major toxicity of their parent anti-kinetoplatidal diarylideneacetones through a prodrug effect. Novel diastereoselective methodologies were developed and generalized from diarylideneacetones and 2,6-diaryl-4H-tetrahydro-thiopyran-4-ones to allow the introduction of a wide substitution profile and to prepare the related S-oxides. The in vitro biological activity and selectivity of diarylideneacetones, 2,6-diaryl-4H-tetrahydro-thiopyran-4-ones, and their S-sulfoxide and sulfone metabolites were evaluated against Trypanosoma brucei brucei, Trypanosoma cruzi, and various Leishmania species in comparison with their cytotoxicity against human fibroblasts hMRC-5. The data revealed that the sulfides, sulfoxides, and sulfones, in which the Michael acceptor sites are temporarily masked, are less toxic against mammal cells while the anti-trypanosomal potency was maintained against T. b. brucei, T. cruzi, L. infantum, and L. donovani, thus confirming the validity of the prodrug strategy. The mechanism of action is proposed to be due to the involvement of diarylideneacetones in cascades of redox reactions involving the trypanothione system. After Michael addition of the dithiol to the double bonds, resulting in an elongated polymer, the latter—upon S-oxidation, followed by syn-eliminations—fragments, under continuous release of reactive oxygen species and sulfenic/sulfonic species, causing the death of the trypanosomal parasites in the micromolar or submicromolar range with high selectivity indexes. [ABSTRACT FROM AUTHOR]

The iron (III) Schiff base complex was immobilized on magnetic silica as well as mesoporous silica substrates and characterized by XRD, TEM, FT-IR, AAS, VSM techniques, and in the case of mesoporous silica, it was also identified with N2 adsorption/desorption and TGA methods. These materials were applied for oxidation of benzyl alcohols and sulfides with hydrogen peroxide as a green oxidant. The effect of catalyst structures was studied in the mentioned reactions. The results showed that using of mesoporous silica in the oxidation of sulfides and benzyl alcohols with hydrogen peroxide in the optimal reaction conditions provided a higher catalytic yield in the same or even less reaction time. The higher catalytic performance of the mesoporous substrate based on the identifications (carried out by N2 adsorption/desorption technique) can be attributed to the higher surface area of this substrate and the stronger connection of the Schiff base complex of iron (III) to the mesoporous silica (according to leaching test). [ABSTRACT FROM AUTHOR]