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The genus Cercis, belonging to the Fabaceae family, is widely distributed in China and traditionally employed in Chinese medicine to treat various disorders, like irregular menstruation, pain, cough and carbuncle swelling. Despite the availability of numerous scientific studies on this genus, reviews that comprehensively cover its phytochemistry and pharmacology remain limited. This review aims to systematically consolidate the scientific literature on the phytochemistry and pharmacology of eight Cercis species, retrieved from databases like PubMed, Web of Science, SciFinder, Google Scholar, and the China National Knowledge Infrastructure platform. Based on a thorough analysis of the literature, more than 100 compounds have been identified from Cercis species, including flavonoids, phenols, terpenoids, lignins, dibenz[b,f]oxepins and others. Extracts and chemical constituents derived from Cercis species exhibited significant antioxidant, analgesic, anti-inflammatory, antitumor, antibacterial activities. These findings contribute to a deeper understanding of the medicinal potential of Cercis species and their potential applications in healthcare. [ABSTRACT FROM AUTHOR]

Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. We wish to confirm that there are no known conflicts of interest associated with this publication and there has been no significant financial support for this work that could have influenced its outcome. RIFM staff are employees of the Research Institute for Fragrance Materials, Inc. (RIFM). The Expert Panel receives a small honorarium for time spent reviewing the subject work.

Graphical abstract Highlights • A copper catalyzed seven-membered ring system is described. • A new synthetic method of the π-extended oxepins is developed. • Photophysical properties of π-extended oxepins are disclosed. Abstract π-Extended oxepins 1 and dimer 8 were synthesized by the benzannulation of the corresponding asymmetric diarylacetylene derivatives and 2-(phenylethynyl)benzaldehyde followed by the Cu-catalyzed intramolecular cyclization. The optical properties of the π-extended oxepins 1 and 8 are also investigated. [ABSTRACT FROM AUTHOR]

CuCl/TMEDA-promoted halogen atom transfer radical cyclization (HATRC) of dichloroacetic acid 1-(3-methyl-but-2-enyl)-naphthalen-2-yl ester in refluxing DCE gave chlorine containing 7-member lactone 3-Chloro-2-(1-chloro-1-methyl-ethyl)-2,3-dihydro-1H-naphtho[2,1-b]oxepin-4-one via 7-exo trig radical cyclization reaction. The structure of the Lactone was confirmed by X-ray diffraction data. [ABSTRACT FROM AUTHOR]

A series of oligonaphthodioxepins was synthesized, revealing a helically arranged octamer, ( R, R, R, R, R, R, R)- 3, which showed intense circularly polarized luminescence (CPL) both in solution and in the solid state. The fluorescence quantum yields (ΦFL) in solution and in the solid state were 0.90 and 0.22, respectively, and the glum values in solution and in the solid state were +2.2×10−3 and +7.0×10−3, respectively. This is one of the highest solid-state CPL glum values yet reported. The high ΦFL and glum values were due to the rigidity, as well as to the fact that ( R, R, R, R, R, R, R)- 3 was a non-planar molecule. Moreover, ( R, R, R, R, R, R, R)- 3 was highly stable both chemically and stereochemically. [ABSTRACT FROM AUTHOR]

A tandem oxidative ring expansion of a six- to seven-membered ring was developed to construct a new class of negatively curved polycyclic arenes embedded with oxepine and thiepine, namely, dibenzo[ b , f ]phenanthro[9,10- d ]oxepine (DBPO) and dibenzo[ b , f ]phenanthro[9,10- d ]thiepine (DBPT), respectively. Mechanistic studies disclosed that an unexpected [4 + 2] cycloadduct formed between the alkene moiety of o -biphenyl-linked methylenexanthenes and o -chloranil serves as a radical cation or a dication equivalent that facilitates the FeCl 3 -mediated tandem ring expansion process.

[Display omitted] Empetroxepins A and B, which are 10,11-dihydrodibenz[ b , f ]oxepins produced by the Black Crowberry (Empetrum nigrum), displayed weak anti-tubercular activity upon isolation, but have not been explored for antibiotic activity despite their molecular similarity to other phenolic antibacterial natural products. Herein we detail the first total synthesis of Empetroxepins A and B via a selective demethylation strategy and antibacterial structure activity relationship (SAR) study of the natural products and related analogs. Empetroxepin A was found to be weakly active against susceptible strains of Staphylococcus aureus (SA) and Bacillus subtilis (BS) with a minimum inhibitory concentration (MIC) of 256 μg/mL against both bacteria, whereas Empetroxepin B was found to be weakly active against only BS (MIC = 256 μg/mL). Neither natural product was active against Escherichia coli (EC). Antibiotic activity was improved through derivatization of the 10,11-dihydrodibenz[ b , f ]oxepin core with the best compound of the SAR series, 9-chloro-10,11-dihydrodibenzo[ b , f ]oxepine-2,3,4-triol, having MICs of 8 μg/mL, 16 μg/mL, and 256 μg/mL against SA, BS, and EC respectively. [ABSTRACT FROM AUTHOR]

Three pairs of new isopentenyl dibenzo[b,e]oxepinone enantiomers, (+)-(5S)-arugosin K (1a), (--)-(5R)-arugosin K (1b), (+)-(5S)-arugosin L (2a), (--)-(5R)-arugosin L (2b), (+)-(5S)-arugosin M (3a), (--)-(5R)-arugosin M (3b), and a new isopentenyl dibenzo[b,e]oxepinone, arugosin N (4), were isolated from a wetland soil-derived fungus Talaromyces flavus, along with two known biosyntheticallyrelated compounds 5 and 6. Among them, arugosin N (4) and 1,6,10-trihydroxy-8-methyl-2-(3-methyl- 2-butenyl)-dibenz[b,e]oxepin-11(6H)-one (CAS: 160585-91-1, 5) were obtained as the tautomeric mixtures. The structures of isolated compounds were determined by detailed spectroscopic analysis. In addition, the absolute configurations of these three pairs of new enantiomers were determined by quantum chemical ECD calculations. [ABSTRACT FROM AUTHOR]

Experimental investigation of hexachlorocyclopentadiene [4+2]-cycloaddition to 2-substituted 4,7-dihydro-1,3-dioxepins revealed an atypical stereochemical effect. Clear experimental evidence was obtained that more bulky C2 substituents favour the thermodynamically and sterically less favourable endo -isomers. The possible reasons for such behaviour are secondary interactions of the highest occupied and lowest unoccupied orbitals in the transition state for endo- cycloaddition, diastereotopic solvation and coordination of the attacking diene reagent to the acetal oxygens. The reaction stereoselectivity also depends on the solvent nature and reaction temperature. We have also found that microwave irradiation significantly influences the [4+2]-cycloaddition yields and stereochemistry, though the nature of the underlying effects remains unclear. [ABSTRACT FROM AUTHOR]

Dibenzo[ b , f ]oxepine is an important scaffold in medicinal chemistry and its derivatives occur in several medicinally important plants. A new approach to methoxydibenzo[ b , f ]oxepines ( 15 – 21 ) proceeding under mild reaction conditions, has been developed. Notably, the use of sodium azide in the reaction allows access to new substituted dibenzo[ b , f ]oxepines. In order to study their shape and conformation, the optimum structures of these compounds were calculated using the DFT B3LYP/6-311++G(2d,p) method. A docking simulation was performed to insert compound 20 into the crystal structure of tubulin at the colchicine binding site to determine the probable binding model. The information from this work can be helpful for the investigation of new tubulin polymerization inhibitors exhibiting stronger activity. [ABSTRACT FROM AUTHOR]

The thermal decomposition of fulvene endoperoxides ordinarily proceeds via an allene oxide intermediate affording oxepin-2(3 H )-one derivatives. We have now uncovered new, unusual pathways in these decompositions where the presence of a hydroxyl group on the alkyl or aryl attached to the fulvene exocyclic double bond has a profound effect on the fate of the reactive intermediates derived from the unstable endoperoxides. Computational work supports the proposed mechanistic pathways. [ABSTRACT FROM AUTHOR]

The mechanistic study of the cycloaddition reaction of nitrous oxide onto sumanene nanostructure carried out systematically using quantum chemistry methods. The 1,3-dipolar cycloaddition reaction of nitrous oxide with different kinds of C–C bond of sumanene in thirteen pathways was investigated. Geometry of reactants, transition states, intermediates and products were optimized at B3LYP/6-311+G(d) level of theory. Vibrational frequencies and relative energies for all stationary points were determined. Thirty-three transition states were identified for all pathways and confirmed by intrinsic reaction coordinate (IRC) calculations. The rate constants for all paths were calculated by using canonical transition state theory (CTST). Results showed that N 2 O addition to flank position is more favorable than other positions of sumanene, energetically. The major products are sumanene with an epoxide group in flank, spoke and hub6 positions; also products with an enol or oxepin group in rim and hub5 positions, respectively. Also, for all five positions, in the first step, C 21 H 12 N 2 O with a pentagon heterocycle contain O–N–N will be formed. In subsequent steps, either N 2 extrusion or rearrangement can be done. Products related to outer positions of sumanene are more stable than corresponding products related to middle positions of sumanene (hub and spoke). [ABSTRACT FROM AUTHOR]

The cytochromes P450 are hemoproteins that catalyze a range of oxidative C−H functionalization reactions, including aliphatic and aromatic hydroxylation. These transformations are important in a range of biological contexts, including biosynthesis and xenobiotic biodegradation. Much work has been carried out on the mechanism of aliphatic hydroxylation, implicating hydrogen atom abstraction, but aromatic hydroxylation is postulated to proceed differently. One mechanism invokes as the key intermediate an arene oxide (and/or its oxepin tautomer). Conclusive isolation of this intermediate has remained elusive and, currently, direct formation of phenols from a Meisenheimer intermediate is believed to be favored. We report here the identification of a P450 [P450cam (CYP101A1) and P450cin (CYP176A1)]-generated arene oxide as a product of in vitro oxidation of tert-butylbenzene. Computations (CBS-QB3) predict that the arene oxide and oxepin have similar stabilities to other arene oxides/oxepins implicated (but not detected) in P450-mediated transformations, suggesting that arene oxides can be unstable terminal products of P450-catalyzed aromatic oxidation that can explain the origin of some observed metabolites. [ABSTRACT FROM AUTHOR]

A simple and facile approach for the synthesis of various structurally different tricyclic bent oxepine frameworks from a readily accessible precursor has been introduced. The synthesis of substituted oxepine derivative involved Pd(0)-catalyzed Heck reaction. This methodology enriches the literature for the large ring formation. [ABSTRACT FROM PUBLISHER]

A novel method for the generation of o -quinodimethane ( o -QDM) intermediates is reported using a mild and efficient base-promoted ring-opening of benzo[ c ]oxepines. Among the benzo[ c ]oxepines studied, indanone containing analogues demonstrated the greatest variety of reactivity. A number of decay modes were observed, in addition with trapping of the o -QDM intermediates using dienophiles for the synthesis of polysubstituted tetrahydronaphthalenes with high regioselectivity. This research provided a novel method to generate o -QDM intermediates from benzo[ c ]oxepine precursors. [ABSTRACT FROM AUTHOR]

A short and efficient method was developed for the synthesis of 2-benzoxepin-3(1H)-ones. The synthetic sequence comprises of initial intermolecular Heck coupling, followed by reduction of the carbonyl functionality of the Heck product and finally base-induced intramolecular condensation. Notably, the final condensation may proceed by an interesting oxy-Michael addition, cycloreversion via double bond isomerization and intramolecular condensation. [ABSTRACT FROM AUTHOR]

A rhodium(III)-catalyzed cross-coupling of benzyl thioethers and aryl carboxylic acids through the two directing groups is reported. Useful structures with diverse substituents were efficiently synthesized in one step with the cleavage of four bonds (CH, CS, OH) and the formation of two bonds (CC, CO). The formed structure is the privileged core in natural products and bioactive molecules. This work highlights the power of using two different directing groups to enhance the selectivity of a double CH activation, the first of such examples in cross-oxidative coupling. [ABSTRACT FROM AUTHOR]

The high-energy insensitive compound trifurazano-oxacycloheptatriene (TFO) was first by synthesized through special etherification. The reaction mechanism and reaction conditions were discussed. TFO has a low melting point (78.6 °C) and good compatibility. TFO is insensitive to impact and friction and has similar detonation velocity (7.7 km s−1) and detonation pressure (35.6 GPa) to RDX. [ABSTRACT FROM AUTHOR]

A facile double allylation/ring-closing metathesis/Claisen rearrangement route for preparing vinylcyclopropanes 6 is developed. The efficient synthesis includes O-allylation of α-allyl-α-sulfonylketones 8 with allylic bromides, ring-closing metathesis of diallyl compounds 9 and sequential Claisen rearrangement of the resulting oxepines. [ABSTRACT FROM AUTHOR]

Seven undescribed polyketides with particular ortho-trisubstituted benzo[c]furan and benzo[c]oxepin spiro structures were isolated from Rhodiola tibetica endophytic fungus Alternaria sp. HJT-Y7. Structural elucidations of these compounds were determined mainly by NMR and HR-ESI-MS analysis. An assumed polyketide biosynthetic pathway of these isolates was proposed. Two undescribed compounds and four known compounds showed significant inhibitory effects on LPS-induced NO production in RAW 264.7 cells without cytotoxicity at their effective concentrations., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Highlights: [•] Ring-opening of gem-dihalo-1,2-cyclopropanated oxyglycals to chloro-oxepines is reported. [•] AgOAc mediated ring opening leads to formation of chloro-oxepines, exclusively. [•] Isomerization of C2–C3 double bond to C1–C2 is the key for rearrangement in halo-oxepines. [•] Oxy-substituent at C-3 generates more substituted C2–C3 double bond. [•] The more substituted C2–C3 double bond prevents further rearrangement. [Copyright &y& Elsevier]

The enantioselective formal synthesis of (-)-isolaurepinnacin and (+)-rogioloxepane A has been achieved. The key steps are an intermolecular Nicholas reaction with a β-hydroxy-γ-lactone as the nucleophile, to form branched linear ethers, and an olefin ring-closing metathesis to obtain the oxepene core. [ABSTRACT FROM AUTHOR]

Highlights: [•] Benzoyl oxiranes act as substrates for the benzofurooxepinones. [•] A novel, environmentally benign photochemical approach for the synthesis of benzofurooxepinones. [•] Furo-oxepinone ring formation via [3+2] cycloaddition. [•] 2-Arylbenzo[b]furo[2,3-e]oxepin-10(4H)-ones may have pharmaceutical importance. [ABSTRACT FROM AUTHOR]

Abstract: An efficient and practical method for the synthesis of cyano, sulfonyl and phosphoryl substituted naphthalene derivatives via the rearrangement aromatization of benzo[c]oxepine has been developed. The system holds the advantages of metal catalysts free, and mild reaction conditions. [Copyright &y& Elsevier]

The very rapid benzene oxide/oxepin equilibrium plays an important role in the metabolism of benzene by cytochrome P450. Although it is the benzene oxide valence tautomer that is attacked by nucleophiles and rearranges to phenols in acidic media, it is the oxepin valence isomers that suffer one-electron oxidation. However, some other reactions are more competitive and also furnish useful illustrations of the Curtin–Hammett principle. For example, while oxepin and benzene oxide are comparable in energy, the only reaction product with maleic anhydride is the Diels–Alder adduct with benzene oxide. Density function theory (B3LYP/6-31G*) calculations are employed for study of three sets of benzene oxide/oxepin equilibria and Diels–Alder reactions with maleic anhydride and dimethylazodicarboxylate as well as epoxidation by dioxirane. Comparisons are made between theory and published experimental data. [ABSTRACT FROM AUTHOR]

Fiveseries of metabolically stable disubstituted dibenzo[b,e]oxepin-11(6H)-oneswere synthesized and tested in a p38α enzyme assay for theirinhibition of tumor necrosis factor-α (TNF-α) releasein human whole blood. Compared to the monosubstituted dibenzo[b,e]oxepin-11(6H)-onederivatives, it has been shown that the additional introduction ofhydrophilic residues at position 9 leads to a substantial improvementof the inhibitory potency and metabolic stability. Using protein X-raycrystallography, the binding mode of the disubstituted dibenzoxepinonesand the induction of a glyince flip in the hinge region were confirmed.The most potent compound of this series, 32e, shows anoutstanding biological activity on isolated p38α, with an IC50value of 1.6 nM, extraordinary selectivity (by a factor>1000, Kinase WholePanelProfiler), and low ATP competitiveness.Theability to inhibit the release of TNF-α from human whole bloodwas optimized down to an IC50value of 125 nM. With thepromising dibenzoxepinone inhibitor 3i, a pharmacokineticstudy in mice was conducted. [ABSTRACT FROM AUTHOR]

A Rh(III)-catalyzed [5+2] annulation of vinyl tyrosines with symmetrical and unsymmetrical internal alkynes was achieved, furnishing a series of oxepine-mounted tyrosine-based unnatural amino acids. In addition, the chemical applicability of the developed strategy was exemplified by stapling amino acid/peptide-appended alkynes with vinyl tyrosines and late stage functionalization of tyrosine-containing dipeptides and tripeptide with internal alkynes.

A divergent formal synthesis of polyhydroxylated macrocyclic lactone (+)-aspicillin and polyene bioactive natural product β-parinaric acid and the total synthesis of non-terpenoid metabolite isolaurepan have been achieved using a ruthenium-catalyzed stereo- and chemoselective oxidative coupling reaction of easily accessible vinyl ketones and acrylates. The crucial transformation involves the efficient synthesis and functionalization of stereodefined ( E,E )-1,6-dioxo-2,4-dienes using simple reaction protocols, which enabled straightforward access to a diverse range of bioactive natural products.

This paper deals with a technology of coal beneficiation focusing on the process of flotation. It reviews and describes practices applied by the Coal Beneficiation Plant of Paskov. Samples of raw sludge were subject of flotation tests conducted at the laboratories of the VSB-Technical University of Ostrava. The objective of the testing was to compare effectiveness of the flotation agents utilized. The paper provides for the statistics of the flotation test results. [ABSTRACT FROM AUTHOR]

A simple, convenient, and efficient method for the formation of functionalized dibenzo[ b, f]oxepins and their analogs bearing both electron-donating and electron-withdrawing groups has been developed via a one-pot cascade reaction. Most starting materials are commercially available 2-(2-hydroxyphenyl)acetonitriles and 2-haloarylaldehydes. The procedure makes use of Cs2CO3 as the base, and DMF as solvent under copper-assisted/copper-free conditions. The reaction has a comprehensive group tolerance for substrates. Most of the reactions were complete within 1 h in good-to-excellent yields, and the reaction temperatures were relatively low. The protocol could be scaled up to grams without lowering the yield. A reaction mechanism was also proposed. [ABSTRACT FROM AUTHOR]

Carbohydrate-based oxepines are seven-membered-ring oxacycles containing an enol ether moiety. These compounds have been used as intermediates in the preparation of septanose carbohydrates by functionalization through their double bond. Reported here is a new synthesis of a carbohydrate based oxepine that uses 2,3;4,6-di- O -acetonide mannose as a key starting material. The oxepine is an important precursor used in the synthesis of septanose glycomimetics of mannopyranosides. The central feature of the synthesis is a two-step sequence that converts a septanose 1,2-di- O -acetate to the septanosyl bromide and onward to the oxepine via a reductive elimination.

A spiro-oxepin isoxazoline skeleton was constructed via 1,3-dipole cycloaddition as a key step, which enabled the total syntheses of 7-deoxyceratinamide A and 7-deoxypsammaplysins K and O. The developed chemistry could be applied to total synthesis of structurally diverse spiro-oxepin isoxazoline-based marine natural products.

A novel and facile methodology for the synthesis of sulfonated benzo[ b ]oxepinone and chromane derivatives was reported by the reaction of propargyl chalcones with arylsulfonyl chloride via radical cascade annulation/sulfonation under laboratory conditions. Readily available propargyl chalcones, commercialized arylsulfonyl chloride, and simple reaction conditions make this six(seven)-membered oxygen-containing heterocycles' synthetic strategy more attractive and with significant application values.

Abstract: Previously we reported the identification of a new oxepin-containing diketopiperazine-type marine fungal metabolite, named protuboxepin A which showed antiproliferative activity in several cancer cell lines. In this study we elucidated the mechanism by which protuboxepin A induces cancer cell growth inhibition. Here we report that protuboxepin A induced round-up morphology, M phase arrest, and an increase in the subG1 population in tumor cells in a dose dependent manner. Our investigations revealed that protuboxepin A directly binds to α,β-tubulin and stabilizes tubulin polymerization thus disrupting microtubule dynamics. This disruption leads to chromosome misalignment and metaphase arrest which induces apoptosis in cancer. Overall, we identified protuboxepin A as a microtubule-stabilizing agent which has a distinctly different chemical structure from previously reported microtubule inhibitors. These results indicate that protuboxepin A has a potential of being a new and effective anti-cancer drug. [Copyright &y& Elsevier]

Abstract: An efficient synthetic route to the putative biosynthetic intermediate of the anti-plasmodial natural product janoxepin is described. This novel enamine-containing pyrazino[2,1-b]quinazoline-3,6-dione, and its synthetic precursors, should be of value in studies to elucidate the biosynthetic pathway leading to the oxepine family of natural products. The cornerstones of the synthesis are amide coupling, pyrazino[2,1-b]quinazoline-3,6-dione construction and aldol introduction of the enamine. [Copyright &y& Elsevier]

Some fused dihydrooxepino[f]-, [g]-, and [h]coumarins were obtained from the ring-closing metathesis of the corresponding o-allyl-allyloxycoumarins under the treatment with the first generation Grubbs' catalyst. These compounds were tested in vitro for their antioxidant activity, and they present significant scavenging activity. They were also showed to inhibit in vitro soybean lipoxygenase. [ABSTRACT FROM AUTHOR]

A reaction of a lithiated derivative of 4,4,5,5-tetramethyl-3-oxido-4,5-dihydro-1 H-imidazole 1-oxyl with 3,6-di- tert-butyl- o-benzoquinone at −80 °C predominantly gave spin-labeled dihydrooxepine via nucleophilic 1,2-addition of the paramagnetic carbanion to the CO group of the benzoquinone followed by insertion of the O atom into the ring. At lower temperatures, this reaction was accompanied by 1,4-addition of the organolithium compound to the benzoquinone followed by oxidation of the resulting adduct into spin-labeled o-benzoquinone. This 'one pot' process is a novel approach to organic derivatives that can further be converted into di- and polyradicals combining nitronyl nitroxide and semiquinolate fragments. [ABSTRACT FROM AUTHOR]

Abstract: Derivatives from the aminobenzosuberone family have been recently synthesized and recognized as highly selective inhibitors of aminopeptidase N (APN)/CD13 (EC 3.4.11.2), an important target for cell migration processes involved in particular in tumor invasion. We present here a much more straightforward synthesis of analogues belonging to a novel isosteric oxo series which also possesses excellent inhibitory potential against APN. Their synthesis, as reported here, relied on an interesting iodine(III)-mediated rearrangement originally described by Koser and Justik as the key step. This represents the second application of this rearrangement in medicinal chemistry. [Copyright &y& Elsevier]

The widespread, long sought-after bacterial aerobic phenylalanine/phenylacetate catabolic pathway has recently been elucidated. It proceeds via coenzyme A (CoA) thioesters and involves the epoxidation of the aromatic ring of phenylacetyl-CoA, subsequent isomerization to an uncommon seven-membered C-O-heterocycle (oxepin-CoA), and non-oxygenolytic ring cleavage. Here we characterize the hydrolytic oxepin-CoA ring cleavage catalyzed by the bifunctional fusion protein PaaZ. The enzyme consists of a C-terminal (R)-specific enoyl-CoA hydratase domain (formerly MaoC) that cleaves the ring and produces a highly reactive aldehyde and an N-terminal NADP+-dependent aldehyde dehydrogenase domain that oxidizes the aldehyde to 3-oxo-5,6-dehydrosuberyl-CoA. In many phenylacetate-utilizing bacteria, the genes for the pathway exist in a cluster that contains an NAD+-dependent aldehyde dehydrogenase in place of PaaZ, whereas the aldehyde-producing hydratase is encoded outside of the cluster. If not oxidized immediately, the reactive aldehyde condenses intramolecularly to a stable cyclic derivative that is largely prevented by PaaZ fusion in vivo. Interestingly, the derivative likely serves as the starting material for the synthesis of antibiotics (e.g. tropodithietic acid) and other tropone/tropolone related compounds as well as for ω-cycloheptyl fatty acids. Apparently, bacteria made a virtue out of the necessity of disposing the dead-end product with ring hydrolysis as a metabolic branching point. [ABSTRACT FROM AUTHOR]

We describe a stereoselective synthesis of isonucleosides of cis and trans configuration using the furan approach, hence enlarging the scope of our methodology. [ABSTRACT FROM AUTHOR]

Aromatic compounds constitute the second most abundant class of organic substrates and environmental pollutants, a substantial part of which (e.g., phenylalanine or styrene) is metabolized by bacteria via phenylacetate. Surprisingly, the bacterial catabolism of phenylalanine and phenylacetate remained an unsolved problem. Although a phenylacetate metabolic gene cluster had been identified, the underlying biochemistry remained largely unknown. Here we elucidate the catabolic pathway functioning in 16% of all bacteria whose genome has been sequenced, including Escherichia coil and Pseudomonas putida. This strategy is exceptional in several aspects. Intermediates are processed as CoA thioesters, and the aromatic ring of phenylacetyl-CoA becomes activated to a ring 1,2-epoxide by a distinct multicomponent oxygenase. The reactive nonaromatic epoxide is isomerized to a seven-member O-heterocyclic enol ether, an oxepin. This isomerization is followed by hydrolytic ring cleavage and β-oxidation steps, leading to acetyl-CoA and succinyl-CoA. This widespread paradigm differs significantly from the established chemistry of aerobic aromatic catabolism, thus widening our view of how organisms exploit such inert substrates. It provides insight into the natural remediation of man-made environmental contaminants such as styrene. Furthermore, this pathway occurs in various pathogens, where its reactive early intermediates may contribute to virulence. [ABSTRACT FROM AUTHOR]

Abstract: Poly (3,3-dimethyl-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepine), PProDOT-Me2, is one of the most promising conducting polymers in the alkylenedioxythiophene based family for electrochromic window applications. In the electropolymerization kinetic study of 3,3-dimethyl-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepine (ProDOT-Me2), microgravimetry and chronoamperometry were used to determine the reaction orders with respect to the electrolyte and monomer, and the corresponding general kinetic equation of electropolymerization. This study presents that monomer concentration has a strong impact on electropolymerization mechanism. The relationship between film thickness and polymerization time was analyzed indicating that saturation of polymerization reduced the increase rate of film thickness with polymerization time. Also, the electropolymerization conditions were optimized to reach high contrast (Δ%T >70%) with the minimum of transmittance (%T min <1) for electrochromic window applications. [Copyright &y& Elsevier]