Neutral and Anion Species of Quinoidal Thienothiophene Diketopyrrolopyrroles Display a Common Aggregation Mode.

A comprehensive investigation of two new molecular triads incorporating the diketopyrrolopyrrole unit into a quinoidized thienothiophene skeleton, which is further end-capped with dicyanomethylene (DPP-TT-CN) or phenoxyl groups (DPP-TT-PhO), has been carried out. A combination of UV-Vis-NIR and infrared spectroelectrochemical techniques and cryogenic UV-Vis-NIR absorption spectroscopy supported by theoretical calculations has been used. The main result is the formation of similar H-aggregates in the dimerization process of the neutral molecules and of the charged anionic species. The experimental absorption spectra of the aggregated species are accurately reproduced by quantum chemical calculations using the Spano's model, including excitonic coupling for the dimeric forms and full vibronic resolution of the absorption bands. The strong excitonic coupling taking place is key to understand the electronic structure of the dimeric aggregates and has been instrumental to disentangle the type of H-aggregation. This study is of relevance to get a better understanding of the molecular aggregation of organic p-conjugated chromophores and is useful as a guideline for the refinement of the engineering of molecular materials for which supramolecular design is required.

Dearomative Intramolecular (4+3) Cycloadditions of Thiophenes.

Unexpectedly facile dearomative intramolecular (4+3) cycloadditions of thiophenes with epoxy enolsilanes, providing sulfur-bridged cycloadducts, are reported. A total of fifteen thiophene substrates have been found to undergo (4+3) cycloaddition smoothly to produce endo and exo (4+3) adducts in yields of up to 83 % with moderate to good diastereoselectivity. Complete conservation of enantiomeric purity was observed when the optically enriched epoxide was used. The desulfurizing transformations of the sulfur-bridged skeleton of the cycloadducts provide functionalized 6,7-fused bicyclic frameworks consisting of 1,3-cycloheptadiene subunits. Density functional theory calculations reveal the origins of the facile dearomatization of thiophenes in these (4+3) cycloadditions.

Synthesis of Some Novel Thiophene Analogues as Potential Anticancer Agents.

The aim of this study involves the synthesis novel thiophene analogues that can be used as anticancer medications through a strategic multicomponent reaction connecting ethyl 4-chloroacetoacetate (1), phenyl isothiocyanate, and a series of active methylene reagents, including ethyl acetoacetate (2), malononitrile, ethyl cyanoacetate, cyanoacetamide 6a-c, N-phenyl cyanoacetamide derivatives 13a-c, and acetoacetanilide derivatives 18. This reaction was facilitated by dry dimethylformamide with a catalytic quantity of K2CO3. The resultant thiophene derivatives were identified as 4, 8a-b, 9, 12a-d, 15a-c, and 20a-b. Further reaction of compound 4 with hydrazine hydrate yielded derivative 5, respectively. When compound 1 was refluxed with ethyl 3-mercapto-3-(phenylamino)-2-(p-substituted phenyldiazenyl)acrylate 10a-e in the presence of sodium ethoxide, it produced thiophene derivatives 12a-d. Comprehensive structural elucidation of these newly synthesized thiophene-analogues was accomplished via elemental and spectral analysis data. Furthermore, the study delves into the cytotoxicity of the newly synthesized thiophenes was evaluated using the HepG2, A2780, and A2780CP cell lines. The amino-thiophene derivative 15b exhibited an increased growth inhibition of A2780, and A2780CP with IC50 values 12±0.17, and 10±0.15 µM, respectively compared to Sorafenib with IC50 values 7.5±0.54 and 9.4±0.14. This research opens new avenues for developing thiophene-based anticancer agents.

Characterization of Sulfur-Rich Microbial Organic Matter in Jurassic Carbonates Using Laser-Assisted Mass Spectrometry.

Laser desorption-ionization mass spectrometry (MS) shows great potential for in situ molecular analysis of planetary surfaces and microanalysis of space-returned samples or (micro)fossils. Coupled with pyrolysis gas chromatography-mass spectrometry (Py-GC-MS) in ESA's ExoMars project, this technique could help assess further the origin of sulfur-bearing organic matter (OM) recently detected on Mars. To unravel this potential, we analyzed sulfurized microbial OM from ca. 150 million year-old carbonates with laser desorption-ionization mass spectrometry (single- and two-step: LDI-MS and L2MS), in comparison with time-of-flight secondary-ion mass spectrometry (ToF-SIMS), gas chromatography-mass spectrometry (GC-MS), and Py-GC-MS. We show that LDI-MS and L2MS readily detect sulfur-bearing moieties such as (alkyl)thiophenes and (alkyl)benzothiophenes. The mineral matrix, however, made the identification of sulfur-bearing molecules challenging in our L2MS experiment. The dominance of small aromatic hydrocarbons (≤14 carbons) in the LDI-MS and L2MS of the extracted soluble and insoluble OM and of the bulk rock is consistent with the low thermal maturity of the sediment and contrasts with the predominance of larger polycyclic aromatic structures commonly observed in meteorites with these techniques. We detected inorganic ions, in particular VO+, in demineralized OM that likely originate from geoporphyrins, which derive from chlorophylls during sediment diagenesis. Finally, insoluble OM yielded distinct compositions compared with extracted soluble OM, with a greater abundance of ions of mass-to-charge ratio (m/z) over 175 and additional N-moieties. This highlights the potential of laser-assisted MS to decipher the composition of macromolecular OM, in particular to investigate the preservation of biomacromolecules in microfossils. Studies comparing diverse biogenic and abiogenic OM are needed to further assess the use of this technique to search for biosignatures.

Non-target and target analysis to identify and characterize thiophenes in soil from an abandoned coking plant.

There is concern about the large amounts of aromatic compounds emitted during coking. Previous studies of coking emissions have been focused on polycyclic aromatic hydrocarbons, dioxin-like compounds, phenols, and volatile organic compounds, but previously unidentified compounds produced during coking may also harm human health. Here, the main pollutants in 69 soil samples from an abandoned coking plant were identified by non-target screening using two-dimensional gas chromatography time-of-flight mass spectrometry. Polycyclic aromatic hydrocarbons, long-chain alkanes, and thiophenes were dominant. High concentrations of thiophenes (benzothiophenes, dibenzothiophenes, and benzonaphtholthiophenes) were found. Quantitative analysis of 12 thiophenes (selected because of their concentrations and detection frequencies) was performed, and the concentrations were 0.03-647 µg/g dry weight, which were extremely high compared with concentrations in soil from uncontaminated sites and other industrial sites. Dibenzothiophene and benzo[b]naphtho[2,1-d]thiophene were dominant, accounting for 69% of the total thiophene concentration. Thiophene profiles in very contaminated areas were different from the profile in coal but similar to the profile in tar. Thiophenes in soil at the coking plant may have been supplied in tar leaks, wastewater, coke oven gases, and exhaust gases. A toxicity assessment indicated a strong likelihood of oxidative stress being induced by exposure to multiple thiophenes at the coking plant. The results suggest that thiophene emissions from coking plants should attract more attention than currently.

Development and pharmacological evaluation of a new chemical series of potent pan-ERR agonists, identification of SLU-PP-915.

Estrogen-related receptors (ERR) are an orphan nuclear receptor sub-family that play a critical role in regulating gene transcription for several physiological processes including mitochondrial function, cellular energy utilization and homeostasis. They have also been implicated to play a role in several pathological conditions. Herein, we report the identification, synthesis, structure-activity relationships and pharmacological evaluation of a new chemical series of potent pan-ERR agonists. This template was designed for ERRγ starting from the known acyl hydrazide template and compounds such as agonist GSK-4716 employing a structure-based drug design approach. This led to the preparation of a series of 2,5-disubstituted thiophenes from which several were found to be potent agonists of ERRγ in cell-based co-transfection assays. Additionally, direct binding to ERRγ was established through 1H NMR protein-ligand binding experiments. Compound optimization revealed that the phenolic or aniline groups could be replaced with a boronic acid moiety, which was able to maintain activity and demonstrated improved metabolic stability in microsomal in vitro assays. Further pharmacological evaluation of these compounds showed that they had roughly equivalent agonist activity on ERR isoforms α and ß representing an ERR pan-agonist profile. One potent agonist, SLU-PP-915 (10s), which contained a boronic acid moiety was profiled in gene expression assays and found to significantly upregulate the expression of ERR target genes such as peroxisome-proliferator activated receptor γ co-activators-1α, lactate dehydrogenase A, DNA damage inducible transcript 4 and pyruvate dehydrogenase kinase 4 both in vitro and in vivo.

Design, Synthesis and Aromaticity of an Alternating Cyclo[4]Thiophene[4]Furan.

A new class of conjugated macrocycle, the cyclo[4]thiophene[4]furan hexyl ester (C4TE4FE), is reported. This cycle consists of alternating α-linked thiophene-3-ester and furan-3-ester repeat units, and was prepared in a single step using Suzuki-Miyaura cross-coupling of a 2-(thiophen-2-yl)furan monomer. The ester side groups help promote a syn conformation of the heterocycles, which enables formation of the macrocycle. Cyclic voltammetry studies revealed that C4TE4FE could undergo multiple oxidations, so treatment with SbCl5 resulted in formation of the [C4TE4FE]2+ dication. Computational work, paired with 1 H NMR spectroscopy of the dication, revealed that the cycle becomes globally aromatic upon 2e- oxidation, as the annulene pathway along the outer ring becomes Hückel aromatic. The change in ring current for the cycle upon oxidation was clear from 1 H NMR spectroscopy, as the protons of the thiophene and furan rings shifted downfield by nearly 6 ppm. This work highlights the potential of sequence control in furan-based macrocycles to tune electronic properties.

Flavouring Group Evaluation 21 Revision 6 (FGE.21Rev6): thiazoles, thiophenes, thiazoline and thienyl derivatives from chemical groups 29 and 30.

The Panel on Food additives and Flavourings (FAF) was requested to evaluate the flavouring substances 2,4-dimethyl-3-thiazoline [FL-no: 15.060] and 2-isobutyl-3-thiazoline [FL-no: 15.119] in Flavouring Group Evaluation 21 revision 6 (FGE.21Rev6). FGE.21Rev6 deals with 41 flavouring substances of which 39 have been already evaluated to be of no safety concern when based on the MSDI approach. For [FL-no: 15.060 and 15.119], a concern for genotoxicity was raised in FGE.21. Genotoxicity data have been submitted for the supporting substance 4,5-dimethyl-2-isobutyl-3-thiazoline [FL-no: 15.032] evaluated in FGE.76Rev2. The concerns for gene mutations and clastogenicity are ruled out for [FL-no: 15.032] and for the structurally related substances [FL-no: 15.060 and 15.119], but not for aneugenicity. Therefore, the aneugenic potential of [FL-no: 15.060 and 15.119] should be investigated in studies with the individual substances. For [FL-no: 15.054, 15.055, 15.057, 15.079 and 15.135], (more reliable) information on uses and use levels is needed to (re)calculate the mTAMDIs in order to finalise their evaluation. Provided that information is submitted for [FL-no: 15.060 and 15.119] with respect to potential aneugenicity, that would allow evaluation of these substances through the Procedure, also for these two substances, more reliable data on uses and use levels would be required. Upon submission of such data, additional data on toxicity may become necessary for all seven substances. For [FL-no: 15.054, 15.057, 15.079 and 15.135], information on the actual percentages of stereoisomers in the material of commerce based on analytical data should be provided.

Electrochemical and Spectroscopic (FTIR) Evidence of Conducting Polymer-Cu Ions Interaction.

In this work, we provide electrochemical and spectroscopic evidence of the conducting polymer-heavy metal ion interaction by comparing the electrochemical and spectroscopic behavior (FTIR) of two different conducting polymer-modified electrodes based on 3,4-alkoxythiophenes: 3,4-ethylenedioxythiophene (EDOT) and ortho-xylen-3,4-dioxythiophene (XDOT) during the potentiodynamic stripping of copper. By analyzing the electrochemical and spectroscopic results, it is possible to propose two different copper dissolution processes during the electrochemical stripping process, which depend on the conducting polymer used. With PEDOT matrix, stripping occurs in a two-step pathway, observed as two anodic peaks, involving the formation of the Cu+-PEDOT complex and the subsequent oxidation step of the Cu+ complex to release Cu2+ ions. On the other side, the experiments carried out let us propose the formation of a poorly stable Cu2+-PXDOT complex or a superficial mechanism for the Cu2+ release, characterized by a single stripping signal for this process. Thus, the incorporation of Cu ions into the matrix and the stripping release are intimately related to the chemical structure of the polymer used.

(BO)2 -Doped Tetrathia[7]helicene: A Configurationally Stable Blue Emitter.

Helicenes combine two central themes in chemistry: extended π-conjugation and chirality. Hetero-atom doping preserves both characteristics and allows modulation of the electronic structure of a helicene. Herein, we report the (BO)2 -doped tetrathia[7]helicene 1, which was prepared from 2-methoxy-3,3'-bithiophene in four steps. 1 is formally derived by substituting two (Mes)B-O moieties in place of (H)C=C(H) fragments in two benzene rings of the parent tetrathia[7]helicene. X-ray crystallography revealed a dihedral angle of 50.26(9)° between the two terminal thiophene rings. The (P)-/(M)-1 enantiomers were separated by chiral HPLC and are configurationally stable at room temperature. The experimentally determined enantiomerization barrier of 27.4±0.1 kcal mol-1 is lower than that of tetrathia[7]helicene (39.4±0.1 kcal mol-1 ). The circular dichroism spectra of (P)- and (M)-1 show a perfect mirror-image relationship. 1 is a blue emitter (λem =411 nm) with a photoluminescence quantum efficiency of ΦPL =6 % (cf. tetrathia[7]helicene: λem ≈405 nm, ΦPL =5 %).

The Ethnopharmacological Uses, Metabolite Diversity, and Bioactivity of Rhaponticum uniflorum (Leuzea uniflora): A Comprehensive Review.

Rhaponticum uniflorum (L.) DC. (syn. Leuzea uniflora (L.) Holub) is a plant species of the Compositae (Asteraceae) family that is widely used in Asian traditional medicines in China, Siberia, and Mongolia as an anti-inflammatory and stimulant remedy. Currently, R. uniflorum is of scientific interest to chemists, biologists, and pharmacologists, and this review includes information from the scientific literature from 1991 to 2022. The study of the chemodiversity of R. uniflorum revealed the presence of 225 compounds, including sesquiterpenes, ecdysteroids, triterpenes, sterols, thiophenes, hydroxycinnamates, flavonoids, lignans, nucleosides and vitamins, alkanes, fatty acids, and carbohydrates. The most studied groups of substances are phenolics (76 compounds) and triterpenoids (69 compounds). Information on the methods of chromatographic analysis of selected compounds, as well as on the quantitative content of some components in various organs of R. uniflorum, is summarized in this work. It has been shown that the extracts and some compounds of R. uniflorum have a wide range of biological activities, including anti-inflammatory, antitumor, immunostimulatory, anxiolytic, stress-protective, actoprotective, antihypoxic, anabolic, hepatoprotective, inhibition of PPARγ receptors, anti-atherosclerotic, and hypolipidemic. Published research on the metabolites and bioactivity of R. uniflorum does not include clinical studies of extracts and pure compounds; therefore, an accurate study of this traditional medicinal plant is needed.

Synthesis and Anti-Inflammatory Activity of 2-Amino-4,5,6,7-tetrahydrobenzo[b]thiophene-Derived NRF2 Activators.

This is the first study investigating the nuclear factor (erythroid-derived 2)-like 2 (NRF2) activity of compounds containing a new scaffold, tetrahydrobenzo[b]thiophene. Eighteen compounds were synthesised and confirmed their NRF2 activation through NQO1 enzymatic activity and mRNA expression of NQO1 and HO-1 in Hepa-1c1c7 cells. The compounds disrupted the interaction between Kelch-like ECH-associated protein 1 (KEAP1) and NRF2 via interfering with the KEAP1's Kelch domain. The compounds exhibited anti-inflammatory activity in Escherichia coli Lipopolysaccharide (LPSEc )-stimulated RAW 264.7 cells. The anti-inflammatory activity of the compounds was associated with their ability to activate NRF2. The compounds reversed the elevated levels of pro-inflammatory cytokines (IL-1ß, IL-6, TNF-α, and IFN-γ) and inflammatory mediators (PGE2, COX-2, and NF-κB). The compounds were metabolically stable in human, rat, and mouse liver microsomes and showed optimum half-life (T1/2 ) and intrinsic clearance (Clint ). The binding mode of the compounds and physicochemical properties were predicted via in silico studies.

Synthesis, Molecular Docking Study, and Cytotoxic Activity against MCF Cells of New Thiazole-Thiophene Scaffolds.

Investigating novel compounds that may be useful in designing new, less toxic, selective, and potent breast anticancer agents is still the main challenge for medicinal chemists. Thus, in the present work, acetylthiophene was used as a building block to synthesize a novel series of thiazole-bearing thiophene derivatives. The structures of the synthesized compounds were elucidated based on elemental analysis and spectral measurements. The cytotoxic activities of the synthesized compounds were evaluated against MCF-7 tumor cells and compared to a cisplatin reference drug, and against the LLC-Mk2 normal cell line using the MTT assay, and the results revealed promising activities for compounds 4b and 13a. The active compounds were subjected to molecular modeling using MOE 2019, the pharmacokinetics were studied using SwissADME, and a toxicity radar was obtained from the biological screening data. The results obtained from the computational studies supported the results obtained from the anticancer biological studies.

The Synthetic Potential of Thiophenium Ylide Cycloadducts.

(3+2) cycloaddition reactions are undeniably one of the most robust and versatile synthetic tools in heterocyclic chemistry. The classically required 1,3-dipoles are however limited to three-atom sequences bearing stabilized formal charges in their Lewis structure. The scope of three-atom groupings possible in (3+2) cycloadditions can be greatly expanded by taking of advantage neutral three-atom components (TACs). These groupings result in zwitterionic (3+2) cycloadducts adaptable to multiple outcomes depending on structure and conditions. Herein, the intramolecular (3+2) cycloaddition reaction between alkynyl sulfides (neutral TAC) and alkynes to provide key thiophenium ylide intermediates is first reported. These reactive species provide access to highly substituted fused thiophenes following predictable chemical sequences. Structural features on the obtained thiophenes were highly configurable by judicious choice of both alkynyl sulfide substitution and reaction conditions.

Lewis Base Catalyzed Synthesis of Sulfur Heterocycles via the C1-Pyridinium Enolate.

While the addition of C1-Lewis base enolates to carbonyls and related structures are well established, the related addition to thiocarbonyls compounds are unknown. Herein, we report a reaction cascade in which a C1-pyridinium enolate undergos addition to dithioesters, trithiocarbonates and xanthates. The reaction provides access to a range of dihydrothiophenes and dihydrothiopyrans (28-examples). Mechanistic investigations, including isolation of intermediates, electronic correlation, and kinetic isotope effect studies support the viability of an activated acid intermediate giving rise to the C1-pyridinium enolate which undergoes turnover limiting cyclization. Subsequent formation of a ß-thiolactone regenerates the catalyst with loss of carbon oxysulfide providing the observed products.

Photoredox catalysis powered by triplet fusion upconversion: arylation of heteroarenes.

In this work, the feasibility of triplet fusion upconversion (TFU, also named triplet-triplet annihilation upconversion) technology for the functionalization (arylation) of furans and thiophenes has been successfully proven. Activation of aryl halides by TFU leads to generation of aryl radical intermediates; trapping of the latter by the corresponding heteroarenes, which act as nucleophiles, affords the final coupling products. Advantages of this photoredox catalytic method include the use of very mild conditions (visible light, standard conditions), employment of commercially available reactants and low-loading metal-free photocatalysts, absence of any sacrificial agent (additive) in the medium and short irradiation times. The involvement of the high energetic delayed fluorescence in the reaction mechanism has been evidenced by quenching studies, whereas the two-photon nature of this photoredox arylation of furans and thiophenes has been manifested by the dependence on the energy source power. Finally, the scaling-up conditions have been gratifyingly afforded by a continuous-flow device.

Thiophenes-Naturally Occurring Plant Metabolites: Biological Activities and In Silico Evaluation of Their Potential as Cathepsin D Inhibitors.

Naturally, thiophenes represent a small family of natural metabolites featured by one to five thiophene rings. Numerous plant species belonging to the family Asteraceae commonly produce thiophenes. These metabolites possessed remarkable bioactivities, including antimicrobial, antiviral, anti-inflammatory, larvicidal, antioxidant, insecticidal, cytotoxic, and nematicidal properties. The current review provides an update over the past seven years for the reported natural thiophene derivatives, including their sources, biosynthesis, spectral data, and bioactivities since the last review published in 2015. Additionally, with the help of the SuperPred webserver, an AI (artificial intelligence) tool, the potential drug target for the compounds was predicted. In silico studies were conducted for Cathepsin D with thiophene derivatives, including ADMET (drug absorption/distribution/metabolism/excretion/and toxicity) properties prediction, molecular docking for the binding interaction, and molecular dynamics to evaluate the ligand-target interaction stability under simulated physiological conditions.

Some Natural Photosensitizers and Their Medicinal Properties for Use in Photodynamic Therapy.

Despite significant advances in early diagnosis and treatment, cancer is one of the leading causes of death. Photodynamic therapy (PDT) is a therapy for the treatment of many diseases, including cancer. This therapy uses a combination of a photosensitizer (PS), light irradiation of appropriate length and molecular oxygen. The photodynamic effect kills cancer cells through apoptosis, necrosis, or autophagy of tumor cells. PDT is a promising approach for eliminating various cancers but is not yet as widely applied in therapy as conventional chemotherapy. Currently, natural compounds with photosensitizing properties are being discovered and identified. A reduced toxicity to healthy tissues and a lower incidence of side effects inspires scientists to seek natural PS for PDT. In this review, several groups of compounds with photoactive properties are presented. The use of natural products has been shown to be a fruitful approach in the discovery of novel pharmaceuticals. This review focused on the anticancer activity of furanocoumarins, polyacetylenes, thiophenes, tolyporphins, curcumins, alkaloid and anthraquinones in relation to the light-absorbing properties. Attention will be paid to their phototoxic and anti-cancer effects on various types of cancer.

Effect of Alkynyl Group on Reactivity in Photoaffinity Labeling with 2-Thienyl-Substituted α-Ketoamide.

Minimalist photo-reactive probes, which consist of a photo-reactive group and a tag for detection of target proteins, are useful tools in chemical biology. Although several diazirine-based and aryl azide-based minimalist probes are available, no keto-based minimalist probe has yet been reported. Here we describe minimalist probes based on a 2-thienyl-substituted α-ketoamide bearing an alkyne group on the thiophene ring. The 3-alkyne probe showed the highest photo-affinity labeling efficiency.